Dec 09

The Chevrolet Volt Cooling/Heating Systems Explained

 

[ad#post_ad]The Chevy Volt is equipped with four fully independent cooling systems or “loops”. The power electronics cooling system loop is dedicated to cooling the battery charger and the power inverter module. The battery cooling system cools (or in some cases heats) the 360V high voltage battery. The engine cooling system and heater loop is specific to cooling the gasoline engine and when required, provides heat for the passenger compartment. The electric drive unit cooling system is designed to cool the two motor generator units and electronics within the 4ET50E drive unit transaxle, and provides lubrication for the various gears, bearings, and bushings.

All four systems each utilize their own separate radiator (or rad-partition) for heat exchange, and are sandwiched together and mounted in the traditional location at the front of the engine compartment. These radiators (and internally routed coolants) are primarily cooled by undercar airflow directed by an air-dam, through the radiators. Airflow is augmented by a pair of variable speed, electrically powered (12V) cooling fans controlled by the Engine Control Module (ECM). Within all but the electric drive-unit cooling system, a precise mixture of “premixed” Dexcool® coolant is used as a heat transport medium. The electric drive cooling and lubrication system utilizes Dexron VI®.

*Warning* Due to potential issues with high-voltage safety, the Chevy Volt’s engine cooling, heater, power electronics and battery cooling systems should only be serviced by a qualified factory-trained Volt technician.

*Warning* Steam and scalding liquids from a hot cooling system can blow out and burn you badly. They are under pressure, and if you turn the surge tank pressure cap — even a little — they can come out at high speed. Never turn the cap when the cooling system, including the surge tank pressure cap, is hot. Wait for the cooling system and surge tank pressure cap to cool if you ever have to turn the pressure cap.

*Warning* You can be burned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engine parts are hot enough. Do not spill coolant on a hot engine.

*Warning* The electric cooling fans under the hood can start up even when the engine is not running and can cause injury. Keep hands, clothing, and tools away from any underhood electric fan.
WOT Says: “When topping up or replacing coolants, always use pre-mixed Dexcool® coolant and NEVER add regular green anti-freeze or tap water to ANY of the Volt’s cooling systems. This premix coolant (available at your GM dealer) is essentially a 50:50 mixture of GM Dexcool® (or other GM6277M compliant coolant) and filtered low-silicate, deionized water. The use of deionized water in hybrids, EREVs, and EVs is a necessity to ensure high-voltage isolation and to prevent the internal corrosion of cooling system components.”


The Power Electronics Coolant Loop

The power electronics coolant loop is designed to ensure the main underhood electronics do not overheat during use. The Power Inverter Module (PIM) utilizes high power Insulated Gate Bipolar Transistors (IGBTs) in order to convert DC current from the high-voltage battery into 3-phase AC motor drive signals for the motor generator units. These same devices also convert AC to DC for charging operations during regenerative braking. The normal operation of the IGBTs creates a significant amount of heat.

The plug-in battery charger also rectifies 120-240 volt household alternating current (ac) from the grid into the direct current (dc) necessary to fully charge the high voltage battery.

It is essential that the heat developed by these devices while operating the Volt or when plugged in be dissipated in order to prevent damage to the components. The Chevrolet Volt uses a high flow 12-volt electric pump to create and control the coolant flow which passes through (in order); the plug-in battery charger assembly, the radiator, the power inverter module (PIM), and the and then back to the pump. The power electronics cooling system radiator is the upper half section of a dual radiator assembly that is common with the high voltage battery cooling system.

The power electronics cooling system also uses an air separator device to prevent air-bubbles from affecting cooling performance and utilizes a surge tank that acts as a coolant reservoir, and facilitates the routine addition of coolant via a pressure cap. (See *Warnings*)

The Hybrid Powertrain Control Module 2, controls the coolant pump as well as radiator fan speeds based on a temperature sensors mounted in the radiator. To operate the fans the HPCM2 communicates a FAN SPEED COMMAND to the Engine Control Module (ECM) via the GMLAN (DWCAN) network. The electronics coolant pump will be activated whenever the Volt is “ON” and during 120-240VAC “plug-in” charging.


The High Voltage Battery Cooling / Heating System

The Volt’s T-shaped Lithium Ion battery (~360V) is mounted underneath the car and runs down the center tunnel and beneath the rear seating positions. A pair of quick-coupler fittings create the coolant IN/OUT connections to the high voltage battery housing. Inside the battery housing there are thermal passages that permit coolant to flow in-between the Lithium Ion battery cells. These passages permit the cells to be cooled or heated depending on operational requirements. The coolant inlet to the battery housing includes a debris filter, and a variable high voltage heating element that operates directly off the 360V Lithium Ion battery, and able to accurately heat the coolant when the battery cells are too cold.

As mentioned previously, the battery cooling system shares a radiator assembly (and twin 12-volt variable speed cooling fans) with the power electronics cooling system. The lower section of this dual radiator is used for battery system cooling. The battery cooling system has its own 12-volt coolant pump, a refrigerant to coolant heat exchanger (aka chiller) and a 3-way coolant flow control valve to route coolant through the radiator, the chiller, or bypass. There is also an AIR separator and surge tank that is integrated with the electronics reservoir/tank (a single housing but with 2 separate tanks).

The Hybrid Powertrain Control Module 2 and other networked modules monitor ambient conditions, the battery IN/OUT coolant temperatures, various Li-Ion cell temperature probes, as well as refrigerant temperatures and pressures to establish battery heating or cooling requirements.

The HPCM2 will then selectively turn the coolant pump ON or OFF, positions the coolant flow control valve, and depending on whether cooling or heating is required, request either the electric A/C compressor to operate (cooling), or turn ON the high voltage battery heater(heating) . The battery cooling/heating system can be activated when the vehicle is “ON” and if necessary during charging operations.

As shown in the diagram, when battery HEATING is required the 3-way coolant flow control valve will be in position “A” and permits fast heating of the Lithium Ion cells to quickly permit them to attain a desirable operating temperature in cold weather.

Position “B” will be commanded whenever the Li-Ion battery cells are too hot. By operating the electric air-conditioning compressor, R-134A refrigerant will be throttled by the thermal expansion valve/s and permit super-cooling of the battery coolant as it passes through the chiller unit.

During more temperature stable operating conditions, the flow control valve will typically be commanded to position “C” circulating the flow of battery coolant out to the battery cooling radiator and back to the pump. This route permits temperature stability by controlling cell temperatures through pump control.

The Engine Cooling System and Heater Loop

The engine cooling system (and heater loop) uses the engine radiator, two 12V variable speed radiator fans, an electric coolant heater pump (12V), a coolant flow bypass valve, a high voltage (360V) coolant heater, and a cabin mounted heater core.

The engine coolant flow bypass valve is a controlled by the Hybrid Powertrain Control Module (HPCM2) to assist in regulating passenger compartment comfort based on the availability of engine heat from the 1.4L range-extender engine. The coolant bypass valve separates the engine and the cabin heater coolant loops to prevent heat generated by the high voltage coolant heater for the passenger compartment from dissipating into the engine coolant loop.

The coolant flow bypass valve has two positions. When the engine is OFF (as during electric only EV operation) the valve is commanded to be in engine bypass mode (Shown as Position “A” in the attached diagram). This permits the electric pump to circulate coolant through the 360V heater then through the heater core in a short, efficient loop. For maximum electrical efficiency, feedback from temperature sensors in the passenger compartment and heater coolant loop are used to determine the necessary amount of electric current applied to the high voltage (360V) heating element which is an integral part of the Coolant Heater Control Module (CHCM).

After the engine starts up (in extended range mode for instance) additional engine heat will soon become available to assist the fan driven cabin heater in warming the passenger compartment. At that point flow control valve is commanded to the “linked” position (Shown as position “B” in the attached diagram) and the two coolant loops are then connected. This parallel connection permits the sharing of coolant between the engine and heater core, and subsequently the 360V heating element (CHCM) power level will be reduced and/or cycled OFF/ON as the engine turns on/off during extended range (charge-sustaining) operation in order to maintain cabin comfort utilizing the most efficient heat source.

Whenever the 1.4 liter range extender ICE is ON, coolant through the engine is managed by a conventional belt-driven water pump. A belt driven pump was selected to ensure positive cooling flow whenever ICE is ON, that is automatically varied proportionately with engine speed. The thermostat regulates the normal engine operating temperatures in a conventional fashion, but can be heated electrically to speed opening and regulate flow. Thus the thermostat creates an appropriate flow restriction for the engine cooling loop that promotes a positive coolant flow and helps to limit air cavitation. When the engine is first started and the thermostat remains closed, a hot water bypass line permits heated coolant flow to the electric pump and heater core. Once the thermostat opens, flow will be permitted through the radiator which will maximize cooling yet still allow flow through the heater core loop for passenger compartment heating.

See the simplified diagram below as a reference for the Engine Cooling System and Heater Loop.

Electric Drive Unit Cooling and Lubrication System
The electric drive unit cooling and lubrication system is designed to maintain the internal temperature of the 4ET50 transaxle used in the Volt. This unique electric drive unit contains a pair of motor generator units that are used to propel the Volt using electric power as well as generate electricity to maintain the high voltage battery state-of-charge. Because of the high power levels of these motor generator units (MGU-A is 58 kilowatts and MGU-B has a peak of 116 kilowatts) there is considerable heat generation during operation.

The 4ET50 drive unit utilizes a system of pressurized automatic transmission fluid (Dexron VI®) that is used to :

- create fluid pressure to apply 3 multi-disc clutches and input damper clutch
- lubricate all gears, bearings and bushings
- cool the motor generator units (MGA & MGB) and other components

The necessary pressure is primarily created by a 3-phase A.C. electrical motor/pump assembly within the transaxle. There is also a more conventional mechanically driven gear pump to ensure transmission fluid pressures and flow are always present when the internal combustion engine is running.

An external transaxle cooler outlet fitting directs fluid under pressure into a high pressure line and to the transmission fluid heat exchanger (radiator/cooler) mounted between the engine cooling radiator and air-conditioning condenser. Transmission fluid circulates through the cooler tubes as airflow across the radiator withdraws heat from the fluid. An outlet fitting from the transmission cooler/radiator then directs the cooled Dexron fluid back into the transaxle via the return line. There is a transmission cooler fluid bypass device at the IN/OUT fitting of the cooler so that in the event of a restricted cooler (due to debris or extremely cold temperatures) the bypass valve would open and redirect the fluid back to the transaxle return fitting.

The thermal management systems used by the Chevrolet Volt are an important aspect of its efficient use of various heat energies.
Balancing and utilizing numerous heat sources and dissipation opportunities for useful purpose in order to minimize heat energy loss is a complicated task that the Volt manages admirably. Future iterations of the Voltec powertrain are certain to take even more advantage of the potential thermal resources and maximize efficient use-reuse of energy for maximum efficiency.

The preceding article was written based on the writer’s interpretation of technical data provided by General Motors via the Global Service Information (GSI) System and Raytheon produced Volt training materials. The writer accepts no responsibility for data error, misinterpretation, or omission. Feedback and critique can be forwarded to wopontour@gmail.com
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This entry was posted on Thursday, December 9th, 2010 at 7:15 am and is filed under General. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.

COMMENTS: 176


  1. 1
    Paul L (VoltinME)

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    Dec 9th, 2010 (7:21 am)

    TMI…phew


  2. 2
    Dave

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    Dec 9th, 2010 (7:42 am)

    fascinating?


  3. 3
    sudhaman

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    Dec 9th, 2010 (7:46 am)

    great explanation of the heating and cooling systems


  4. 4
    Mikeinatl

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    Dec 9th, 2010 (7:48 am)

    Cool.


  5. 5
    Rashiid Amul

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    Dec 9th, 2010 (7:48 am)

    From the article
    “When topping up or replacing coolants, always use pre-mixed Dexcool® coolant and NEVER add regular green anti-freeze or tap water to ANY of the Volt’s cooling systems. This premix coolant (available at your GM dealer) is essentially a 50:50 mixture of GM Dexcool® (or other GM6277M compliant coolant) and filtered low-silicate, deionized water.”

    Sounds proprietary to me and proprietary is a four letter word because it is usually very expensive.


  6. 6
    BCool

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    Dec 9th, 2010 (7:50 am)

    Wow, quite the engineering! But, it scares me to think about how many more chances there are for things to break over time…I think I’d be in the market for an extended warranty if they offered one :-)


  7. 7
    Barry252

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    Dec 9th, 2010 (7:51 am)

    This sounds so complicated. Is this why the Leaf has air cooled batteries?


  8. 8
    rob

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    Dec 9th, 2010 (7:53 am)

    I think we just found an area where future models can reduce costs. Holy over-complicated, Batman!


  9. 9
    Exp_EngTech

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    Dec 9th, 2010 (8:01 am)

    Great, Great, Tech Info Lyle !

    Thank You.


  10. 10
    Jim I

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    Dec 9th, 2010 (8:03 am)

    Aren’t we forgetting about a very important cooling system that was not mentioned?

    The one that keep me cool inside the car!!!!!!!!!!!!

    And how about the cabin heating system – The ICE portion was mentioned, but how about when the ICE is not on? Some info about the electric heater and that operation would be good to know. Things like energy use, etc.

    One other thing: Too many disclaimers! We are not going to sue you based on your opinions :-)


  11. 11
    Eco_Turbo

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    Dec 9th, 2010 (8:05 am)

    Elon Musk had an applicable thought in his post mission interview yesterday, regarding how he can do things with less money. He said, paraphrased, of the way NASA operates, “whenever you use legacy systems, you inherit legacy cost structures”. It seems that our, (the public’s), job now, is to buy enough Volts to enable GM to make it’s systems more simplified and efficient with new technology.


  12. 12
    Chris C.

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    Dec 9th, 2010 (8:15 am)

    Hooray, WopOnTour’s article finally got posted!

    Two questions:

    1. Is there a diagram for the battery cooling system, e.g. one showing the A/B/C switch? It seems from the text like there should be.

    2. Can you provide temperature thresholds for the various battery cooling/heating modes, and if so edit them into the article above?


  13. 13
    Roy H

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    Dec 9th, 2010 (8:16 am)

    Whew! That is a long read, I will finish it later.
    My big question is how many watts is the electric cabin heater?


  14. 14
    Chris C.

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    Dec 9th, 2010 (8:19 am)

    Jim I: And how about the cabin heating system – The ICE portion was mentioned, but how about when the ICE is not on?Some info about the electric heater and that operation would be good to know.

    Search the article for the word “cabin”.

    Things like energy use, etc.One other thing:Too many disclaimers!

    Agreed. These are a jarring presence early in the article. Assuming they were mandated by a lawyer, put them inside blockquote boxes, better yet drop the font size, and even better put them at the end.


  15. 15
    Dave G

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    Dec 9th, 2010 (8:20 am)

    I’ll probably get negs for saying this, but it seems the Volt cooling system is more complicated than it needs to be.

    The electronics could probably be air cooled. I believe Tesla and Nissan both do this.

    I do see the need for a separate liquid cooling/heating system for the battery, at least until battery cell durability improves.

    But I don’t see the need for two water pumps on the ICE/heater system. In fact, I don’t see why the Volt ICE needs a belt at all. Power steering is electric. Air conditioning is electric. The generator is connected to the crank shaft. So if there was no belt driven water pump, there would be no belt, pulleys, tensioners, or brackets. In other words, a lot less stuff to go wrong.

    We know ICE electric water pump is 50 watts:
    http://gm-volt.com/2008/10/20/contract-awarded-for-the-chevy-volts-water-pump-system/
    Wouldn’t that be enough to manage the whole ICE/heater system?


  16. 16
    taser54

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    Dec 9th, 2010 (8:27 am)

    Rashiid Amul,

    It’s the same as any toyota car, no silicates in coolant, NO tap water.


  17. 17
    Baltimore17

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    Dec 9th, 2010 (8:31 am)

    Jim I: Some info about the electric heater and that operation would be good to know

    The info is in the writeup.


  18. 18
    Ray@Diy solar panels

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    Dec 9th, 2010 (8:33 am)

    This cooling system is a bit complicated but I don’t think that it’s very expensive and it keeps the battery safe plus more durable.


  19. 19
    Lee

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    Dec 9th, 2010 (8:36 am)

    (click to show comment)


  20. 20
    Baltimore17

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    Dec 9th, 2010 (8:37 am)

    Dave G: it seems the Volt cooling system is more complicated than it needs to be.

    My thought is the reverse: So this is how complicated the Volt cooling system has to be to assure the long life promised by the warranty. On the other hand, it sure looks like the system is ripe for evolutionary value engineering as GM gets field reports on Volt reliability and performance in consumers’ hands.


  21. 21
    joe

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    Dec 9th, 2010 (8:44 am)

    Even a person of little technical expertise can figure out that GM has the best engineers in the world! Who else would risk designing such a huge game changer?

    Great job GM!


  22. 22
    Baltimore17

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    Dec 9th, 2010 (8:46 am)

    My first car, a 1975 Chevy Monza, had three motors: heater fan, wipers and windshield washer pump.

    My second car, a 1982 Trans Am, added two for the hidden headlights, two for the rear wiper/washer, two for the power door locks, two for the power windows, and one for the power antenna. I think that adds up to 12.

    Considering the Volt doesn’t have the rear washer/wiper nor power antenna nor hidden headlights, (that’s five), maybe the total motor count, including all the cooling pumps, isn’t too out of line with various other cars over the years. Pop up nav screens, oscillating A/C vents and 8-way power seats anyone?


  23. 23
    wizland

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    Dec 9th, 2010 (8:51 am)

    Rashiid Amul,

    When servicing my car I prefer to have options. I’m not happy with being told I have to buy anything exclusively from the dealer. I planned on getting my Volt serviced by the dealer because it is such new technology, but I don’t like someone telling me I have to.


  24. 24
    Mark

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    Dec 9th, 2010 (8:51 am)

    I would guess that GM is taking the most conservative path here. A lot is riding on the Voltec technology and the word of heat/cold related premature failures in the vehicle would be distrastrious. Naysayers are always ready to pounce on any non IC vehicle anyway. Once GM gets thousands of vehicles on the road for a few years they will have the data tol know which parts of this system are overkill and which are not.

    It’s really not that complicated as we’re just looking at a conventional cooling system applied in an unconditional matter. As for the Leaf and Tesla drive motor are they housed inside a transmission in close proximity to an internal combusion engine? The Voltec platform presents new opportunities and challenges to engineers.

    I for one am going to trust the GM engineers for now and in 5 years see how many Leafs, Volts, and Tesla’s are driving around on their original battery with 100,000 miles on them.

    - Mark


  25. 25
    Jimza Skeptic

     

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    Dec 9th, 2010 (8:51 am)

    Rashiid Amul: From the article
    “When topping up or replacing coolants, always use pre-mixed Dexcool® coolant and NEVER add regular green anti-freeze or tap water to ANY of the Volt’s cooling systems. This premix coolant (available at your GM dealer) is essentially a 50:50 mixture of GM Dexcool® (or other GM6277M compliant coolant) and filtered low-silicate, deionized water.”Sounds proprietary to me and proprietary is a four letter word because it is usually very expensive.    

    Bottom line is that dealerships and companies make their money on the service side of the business. With increased use of electric power, the ICE requires less service. They have to try to make it up where they can.


  26. 26
    jdenn4698

     

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    Dec 9th, 2010 (8:57 am)

    (zzzzzzzz)

    pfew, I hope there are some smart people here who can tell me what that all means.


  27. 27
    bitguru

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    Dec 9th, 2010 (8:58 am)

    Jim I: And how about the cabin heating system – The ICE portion was mentioned, but how about when the ICE is not on?

    That’s what the 360V electric heater is for. (When the ICE is being run, the heat it generates will be used completely or partially to offset use of the 360V heater.)

    I think it’s interesting that the 360V is not used to heat the battery pack when the weather is cold.

    Dave G: The electronics could probably be air cooled. I believe Tesla and Nissan both do this.

    I know nothing about the Tesla or Nissan, but I can tell you that the power electronics in my 2001 Prius get very hot. I don’t see how they could be air-cooled.


  28. 28
    George S. Bower

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    Dec 9th, 2010 (9:01 am)

    WOT,
    Why did GM decide to heat the battery w/ just electric resistance heat instead of using the freon loop in heat pump mode?? Seems like the heat pump method might be more energy efficient.
    Thx,
    GSB

    Sorry if this was already asked. I just jumped in.


  29. 29
    joe

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    Dec 9th, 2010 (9:05 am)

    BCool,

    With my years working for GM, I’ve worked on machinery having such sophistication…machines costing over a million dollars apiece. And you would be surprised at how many few breakdowns they had working 24/7.

    Most electrical components used in the Volt have been around for a long time and have been time tested, so I would not worry on that part. I think the Volt will be a tough vehicle, both mechanically and electrically.


  30. 30
    MichaelH

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    Dec 9th, 2010 (9:09 am)

    Thanks for all the information, WopOnTour. I had no idea how complicated the systems were. I only knew there were three separate Dexcool® systems. Keep up the good work GM.


  31. 31
    Loboc

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    Dec 9th, 2010 (9:10 am)

    Large article. I’ll finish later. lol.

    Commenting on some of the comments:

    GM certifies fluids in the aftermarket for their ‘proprietary’ items. You shouldn’t have any problems with DIY or using non-GM mechanics.

    Cooling system fluid change is a very rare occurrence. (Need to get a quote from my Volt manual).

    Some are saying this is complicated. Well, I guess it is if you don’t work on cars. It’s not all that complex compared to any other 2011 car. The transmission alone is way simpler.

    Having things like A/C compressors run by their own motor puts way less stress on the start/stop/cycling since you’re not starting at 2000+ rpms. Same thing with over- or under-revs on power steering. Brakes are no longer dependent on vacuum system from engine. All of these sub-systems can be redesigned to fit better into the car. Hose lengths (a large portion of failures) can be shorter or even non-existent.

    Overall, I don’t see complexity, I see steps into the less complex.


  32. 32
    Rashiid Amul

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    Dec 9th, 2010 (9:10 am)

    taser54: Rashiid Amul,
    It’s the same as any toyota car, no silicates in coolant, NO tap water.    

    I didn’t know that. So a Toyota doesn’t use standard anti-freeze?


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    ccombs

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    Dec 9th, 2010 (9:29 am)

    Really well done! Sure, this can be simplified in the future- but it offers a big efficiency advantage for for the Volt to be able to use the heat from the battery and ICE for climate control.

    An LA times review just found the Leaf had 15-20% range reduction with climate control on. I’m from there and of course it isn’t that cold- the problem might be not being able to extract battery heat. 85/80% multiplied by the 73 miles the EPA found for the Leaf is starting to get into not-so-good territory for a lot of people who were told the Leaf is a 100mi range EV (and now try this in Minneapolis or something). I have nothing against the Leaf- I drive a Versa (Leaf is an uglier electric clone) and I can’t wait to see the Leafs two of my relatives are getting. I just really want to see EVs succeed and not acquire a bad reputation that just won’t go away. We have to get it right the first time for a skeptical public to start accepting them. If the batteries also degrade too quickly due to lack of liquid cooling then it could be bad PR that could reflect badly on all EVs.


  34. 34
    Eco_Turbo

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    Dec 9th, 2010 (9:34 am)

    I thought a prior article here on GM-Volt, said that the Volt would use HFO-1234yf, the new refrigerant that’s supposed to appear in “normal” GM cars in 2013.


  35. 35
    James

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    Dec 9th, 2010 (9:36 am)

    Now my big question is maintenance. Cooling and heating the Volt, it’s electronics and passengers is obviously a very complex undertaking. One of the main benefits of an electric car is fewer moving parts equalling simplicity. How much time qnd diligence is required in keeping this cooling system properly, efficiently doing it’s job?

    In other words, am I just trading one kind of mental and financial burden – oil changes, transmission fluid maintenance and engine tune-ups for coolant loop flushing and Dextron changes? Also, how does the Volt communicate to the driver that one of these systems is malfunctioning? Is it just an indicator on the touchscreen – ” needs immediate maintenance”?

    I would like to see a screen on the display that monitors the cooling loops and assures me it’s all in fine working order – or not.

    Thanks WOT for the technical eyeglass. It brings up some good questions.

    PUMP OUT THE VOLTS! ( in all 50 states ),

    James


  36. 36
    WopOnTour

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    Dec 9th, 2010 (9:40 am)

    Chris C.: Hooray, WopOnTour’s article finally got posted!Two questions:1. Is there a diagram for the battery cooling system, e.g. one showing the A/B/C switch? It seems from the text like there should be.2. Can you provide temperature thresholds for the various battery cooling/heating modes, and if so edit them into the article above?  (Quote)  (Reply)

    Chris, as to question 1 . there was one diagram that was left out of the article due to space constraints. (the text description is there though). As for question two, let me get back to you on that. (maybe the forums?)
    WOT

    BatteryCooling_2.jpg


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    Eco_Turbo

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    Dec 9th, 2010 (9:41 am)

    (click to show comment)


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    Dec 9th, 2010 (9:44 am)

    George S. Bower: WOT,
    Why did GM decide to heat the battery w/ just electric resistance heat instead of using the freon loop in heat pump mode?? Seems like the heat pump method might be more energy efficient.
    Thx,
    GSBSorry if this was already asked. I just jumped in.    

    Heat pumps become inefficient at low temperatures. Extreme low temperatures is when the battery would be in most need of being heated.


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    Alex Besogonov

     

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    Dec 9th, 2010 (9:48 am)

    Way, way too overengineered. Also, ability to reuse battery heat to heat passengers should be nice.

    IMO, cooling system improvements would be among the first ones in Volt 2.0


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    Mark Z

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    Dec 9th, 2010 (10:00 am)

    bitguru:
    That’s what the 360V electric heater is for. (When the ICE is being run, the heat it generates will be used completely or partially to offset use of the 360V heater.)I think it’s interesting that the 360V is not used to heat the battery pack when the weather is cold…

    Just to prevent confusion, here is a quote from the article:

    “The coolant inlet to the battery housing includes a debris filter, and a variable high voltage heating element that operates directly off the 360V Lithium Ion battery, and able to accurately heat the coolant when the battery cells are too cold.”

    My questions for WopOnTour are: Is the 360V heating element turned on to keep the high voltage cells above freezing when the Volt high voltage battery has available SOC and the vehicle is turned OFF and parked outside in below freezing weather?

    If not or if the battery is low on power to heat the cells, what is the lowest temperature the Volt can safely sit outside without being plugged in?

    Thanks for a superb article.


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    George S. Bower

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    Dec 9th, 2010 (10:10 am)

    It looks like the schematic just posted shows that the battery heat transfer loop never uses ICE waste heat. wouldn’t this be a better source off “free” heat.—–or am I missing something.


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    Matthew B

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    Dec 9th, 2010 (10:10 am)

    Rashiid Amul,

    You can go to any auto parts store and get the right coolant. GM just doesn’t want you to use regular green stuff mixed with tap water.


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    Dec 9th, 2010 (10:17 am)

    Quite a lot of information. Almost information over-load. Thanks to WOT for the information. I assumed beforehand that the Volt’s heating/cooling systems would be complicated and this article proves my thinking. I just hope that it all works as planned and continues to work for many miles and years trouble-free.


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    neutron

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    Dec 9th, 2010 (10:21 am)

    Experience has proved to me that the KISS (Keep It Simple Student {or stupid}) technique is usually the better solution.

    If this is the most simple option for heating and cooling the VOLT??? Then it is a little scary.
    Complicated solutions can result in more expensive and possibly frequent repairs

    Did I read correctly there is at least 2 different kinds of coolant on the the systems. What happens if they get mixed up?

    The good thing is this system is electronically controlled. The reliability level should be good.
    Maybe by Gen II this system will be proved to be very good or the evolution of design will indeed make it more simple.

    Just my 2 cents.


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    Dec 9th, 2010 (10:29 am)

    Loboc,

    I do hope you are correct. As noted in my post earlier the KISS technique is generally the better choice.


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    James

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    Dec 9th, 2010 (10:39 am)

    I’m not a mechanic, an engineer or a technical person. I used to change my own oil, but never did my own tune-ups, even though I knew how. The most technical thing I do on my cars these days is change a battery or windshield wiper blades, topping off fluids or checking/changing tire pressures. The more sophisticated and computerized cars got, it just made me dependent upon professional specialists to maintain my vehicles. Today I even go to the oil change shop rather than get my hands dirty.

    One thing I’ve learned over the years is to keep educated ( buy manuals, etc. ) on my car’s systems as to be less fleece-able when visiting a local mechanic. My Prius was a whole new step into new territory – it’s the first time I’ve ever purchased a maintenance plan – and I did so because the Prius is so techno-heavy I really don’t want to do more than check the fluid levels, keep the 12v battery charged and keep the engine bay clean. So far, it’s worked out nicely – yet knowing 80% of a car dealership’s profits come from the service dept., I’ve known that, like all my previous vehicles – once the warranty period expires, there is the point where it makes alot more sense to go to independent shops for work since they’re so much less expensive. My 2007 Prius is reaching that milestone – where I hand off service to outside vendors and I hope they’ve had enough years to have trained technicians who are capable at working on hybrids – diagnosing and using proper parts and materials. I’m still unsure of this – yet it seems fairly plausible that with millions of Prii on the road, I’ll be able to find a shop that’ll fit the bill.

    The Volt? No way. With Volt we will be visiting the Chevrolet dealership exclusively, which makes me a bit nervous – as this spells E-X-P-E-N-S-I-V-E and we can be sure that GM has cooked all this into it’s EV recipe since so much of their profits depend on service.

    I wonder how long it will take for us to find EV mechanics in the Yellow Pages internet directory?

    PUMP OUT THE VOLTS! ( in all 50 states ),

    James


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    Dec 9th, 2010 (10:41 am)

    By the Way I forgot to note a THANKS for your article about the Volt healing/cooling system. You have generated good discussion about this area. Thanks again.

    From the article – “The preceding article was written based on the writer’s interpretation of technical data provided by General Motors via the Global Service Information (GSI) System and Raytheon produced Volt training materials. The writer accepts no responsibility for data error, misinterpretation, or omission. Feedback and critique can be forwarded to wopontour@gmail.com


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    Dec 9th, 2010 (10:47 am)

    James,

    I you have a shop or mechanic you trust they will be up front about what they can and cannot do with your car. The Volt will be no exception.
    My experience with trusted mechanics is they are eager to get training on any car that will may become a common item that can benefit from their services.
    In this case it may be 3 to 5 years before Volt maintenance will be common in the wild. :+}


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    Dec 9th, 2010 (10:48 am)

    Thank you for a great explanation of a complicated topic. The heating/cooling system in the Volt is one of many that make this a complex machine. The genius of this will be the simplicity of use. Many of the variables of battery care are taken care of without end user intervention. This is what makes for a KISS electric car.


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    Dec 9th, 2010 (10:54 am)

    George S. Bower: It looks like the schematic just posted shows that the battery heat transfer loop never uses ICE waste heat. wouldn’t this be a better source off “free” heat.—–or am I missing something.    

    It might be a good source but it will not always be available. Plus when it is available it’s not as easy to regulate. With an electric heater you can easily keep the battery at a specific temperature.


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    Dec 9th, 2010 (10:58 am)

    neutron: Experience has proved to me that the KISS (Keep It Simple Student {or stupid}) technique is usually the better solution.If this is the most simple option for heating and cooling the VOLT???Then it is a little scary.
    Complicated solutions can result in more expensive and possibly frequent repairsDid I read correctly there is at least 2 different kinds of coolant on the the systems.What happens if they get mixed up?The good thing is this system is electronically controlled.The reliability level should be good.
    Maybe by Gen II this system will be proved to be very good or the evolution of design will indeed make it more simple.Just my 2 cents.    

    I think most people are missing the fact on most if not all modern GM cars the ICE coolant get change approximately every 100K miles. I don’t know about the motor and battery/electronic coolant, but given you wouldn’t have the impurity issues you normal have with the ICE I imagine it would less often for those coolants.


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    CorvetteGuy

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    Dec 9th, 2010 (11:10 am)

    Simply stated: “When you’re hot, you’re hot. When you’re not, you’re not!”
    :)


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    Dec 9th, 2010 (11:11 am)

    Thx Jim and theflew for your explanations. They make sense.


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    Dec 9th, 2010 (11:12 am)

    Rashiid Amul: From the article“When topping up or replacing coolants, always use pre-mixed Dexcool® coolant and NEVER add regular green anti-freeze or tap water to ANY of the Volt’s cooling systems. This premix coolant (available at your GM dealer) is essentially a 50:50 mixture of GM Dexcool® (or other GM6277M compliant coolant) and filtered low-silicate, deionized water.”Sounds proprietary to me and proprietary is a four letter word because it is usually very expensive.  (Quote)  (Reply)

    As I work for a manufacturer (not automotive but we have specific fluids for some high tech items), sometimes there are very specific reasons for this. Primarily, they tested it and it works, they are not about to test EVERY possible fluid, generally it is up to the alternate manufacturer to test it and prove = to OEM spec, then a manufacturer has to simply review the testing data and say yea or nay…..yes the coolant may cost more, but what if you do what you want, and there isa failure…you WILL have invalidated your warranty by not using what they require. How often are you required to change it? My equinox says change every 5 years, or x miles

    look at it this way, say the special stuff is 800 bucks for a complete change, every 2 years, that is 1600 bucks in maintenance over the battery warranty…but you use the green stuff after the fist change because it is only 50 bucks…then the battery fails…GM sees the green stuff, you invalidated your warranty, that’ll be 10,000 bucks to fix your car + Labour, plus a flush and fill of the coolant, plus tax…

    1600 bucks looks pretty good.

    (all numbers are random ones pulled out of my….and should not be construed as remotely accurate, but are only used to generate a “you get the idea” scenario)


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    DonC

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    Dec 9th, 2010 (11:14 am)

    WOP. let me extend my thanks for your taking the time and for expending to provide such a thorough article. That was a lot of work but it’s greatly appreciated. You’ve given a terrific overview of the cooling systems! I think most of us now have a much better idea of how complex the engineering challenges were than we had before reading your article.

    Also let me extend my thanks to Lyle for providing a forum where you could publish the article.


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    Dec 9th, 2010 (11:20 am)

    A.D.D. kicked in @ “within the 4ET50E drive unit transaxle……”

    Sooooo……
    Whats up with the price of gas? friggin $3.12/gal today. Damn!


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    Dec 9th, 2010 (11:23 am)

    Hey Lyle,

    What did you do differently on 11/28 and 12/08 ( 30.8; 30.6 EV miles ), was it a really cold day? Did you not plug in at work? Did you race home – or take the Volt to the drags? L :) L

    Just curious.

    James


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    Dec 9th, 2010 (11:33 am)

    So, you taking this show on the road, WopOT? All that talk and pics of surge tanks and heat are gonna have ‘em flinging their personal clothing onstage.

    Ho, ho, hoes


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    Chris C.

     

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    Dec 9th, 2010 (11:33 am)

    Lyle, the image that WopOnTour posted in the comments above clearly does belong in the article. Please edit it in. I realize that it’s already a long article, but the image helps make it EASIER to read, both because it will illuminate the text and because it will visually break it up some more.

    And do something with those CYA warnings, as I posted above, please :)


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    Dec 9th, 2010 (11:35 am)

    James,

    You are correct in stating the importance of keeping oneself educated to understand any technology, especially something as the Chevy Volt, and I give you the Helm Inc web page to order the Volt Service Manual Set:
    http://www.helminc.com/helm/Result.asp?Style=helm&Mfg=GMC&Make=CHV&Model=VOLT&Year=2011&Category=&Keyword=&Module=&selected%5Fmedia=

    It isn’t available until April 2011, but most new Volt owners will not see their cars until after April (including myself). So this may be a bit of expensive, but the time and cost savings justify the purchase. I have serviced my four GM vehicles and a few of my family’s GM vehicles (including two Chevy Camaros), so I understand how GM service works. I buy and keep the original Service Manuals (most were bought at Helm Inc), and I plan to buy the Volt manuals before buying the car itself.

    As an Engineer, I understand almost all the procedures and diagrams that GM publishes, and I have done my own modifications to each vehicle as needed (obviously after the factory warrantee expires). I believe that I can service my own Volt with this set, and most of the other fellow members could do the same.

    Since the useage of the ICE depends on CS millage, I believe that the service cost will be much less than for a regular ICE auto, so there will be savings. As soon as GM can produce a BEV with a longer range, then the service costs will be lesser. I give much credit to GM engineers that not just produce a great vehicles (in the past as in the present Volt), but for testing and documenting the Service and Owner Manuals which shows how much they care about their vehicles.

    Anyway, the Volt Service Manual will be a very fascinating read, and provide many new threads and posting about what we find useful, and how we can learn about the Volt itself.

    Raymond


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    Ted in Fort Myers

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    Dec 9th, 2010 (11:44 am)

    OT Just got permission to plug in at work from the highest level of management. They will chage me $0.60/day for what ever portion I need to fill up. Not a bad deal considering they are making people take unpaid days off, cutting back on holiday pay, eliminated overtime, raised the cost on healthcare before and when used. I cannot wait to take delivery of my Volt.

    Take Care, TED


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    Dec 9th, 2010 (11:48 am)

    Many drivers do not read their owner’s manual. If the warnings keep one person safe from injury, then my vote would be to leave them in the article.


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    Dec 9th, 2010 (11:50 am)

    A review about Tesla, Volt and Leaf batteries and management. http://www.technologyreview.com/energy/26832/page1/


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    Dec 9th, 2010 (11:50 am)

    Just finished reading my new Motor Trend CAR OF THE YEAR edition. Found it interesting that with all the accolades, “Moonshot”, they piled upon our beloved Volt, the Cruze got hammered, “Without exception, our comments climbing out of the Chevrolet Cruze went like this, ” You know that’s nota bad little car. Actually, it’s kind of big. Still, I like it. What?!? $26,310? Are they nuts!”

    Evidently, they didn’t drive a stripper. They did say- “Most of us thought this vehicle came in under $20 grand, while it does start at $16,995, the price when nicely optioned takes away much of it’s luster”. Boy, Toyota is gonna run wild with that! I can see Corolla ads touting $18,500 nicely equipped!”. IMHO GM might have got a short stick on Cruze from Motor Trend, since other models in their Car Of The Year assessment had more than one iteration tested, Cruze only one-a deluxe model.

    It brings up some interesting thoughts since GM is banking so much on it’s global car. If Cruze sees luke-warm sales, will Volt be fast-tracked to make up the difference? And, with a top-tier Cruze at nearly $30 grand with tax, license and dealer prep, does that make Volt a halo, or a pretty smart deal for a Chevy buyer?

    PUMP OUT THE VOLTS! ( in all 50 states ),

    James

    Here’s a quote from one Motor Trender I thought you guys and gals might find amusing. In the Car Of The Year Observations section – ” The Volt’s A Technical Marvel, But… As Theodore points out, “It’s like driving a video game without the haptic feedback
    .Some people will like this experience very much, kind of a quiet mindless transporter. It could be very soothing if you’re stuck in a traffic jam on the 405″.

    Even a traditonal car mag that applauds Volt can’t but help the sarcasm. Oh well. Still the COY edition of MT and last month’s test cover story may well be worth purchasing as for it’s historical value, it may become a collector’s item – JM


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    Chevonly

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    Dec 9th, 2010 (11:56 am)

    Nice article and good graphics, we can be sure that japanese engineers already have these diagrams and they have already reverse engineered the Volt so they can avoid any patent laws. They will end up manufacturing a competitive unit probably with cheap communist labor and then sell it to Americans to stupid to know the difference. IS THIS A GREAT COUNTRY OR WHAT.


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    Dec 9th, 2010 (11:57 am)

    Maybe a bit OT here, but for those who want to know how other things work, here is the Helm Inc web page for the 2010 Toyota Prius Service Manuals:
    http://www.helminc.com/helm/Result.asp?Style=helm&Mfg=TMS&Make=TOY&Model=PRIU&Year=2010&Category=&Keyword=&Module=&selected%5Fmedia=

    Notice that it takes up many volumes, and that the full cost is more than for the Volt set.
    You can search for other service and user manuals at this site’s home page.

    Raymond


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    Dec 9th, 2010 (12:05 pm)

    neutron: I you have a shop or mechanic you trust they will be up front about what they can and cannot do with your car. The Volt will be no exception.

    A few times on different cars I was told by my mechanic to go to the dealer for the repair. Oh well, If I don’t want the hassle of specialized repairs I would purchase a Chevy Aveo or similar. An example of KISS


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    Dec 9th, 2010 (12:09 pm)

    Any reliability issues associated with the complicated cooling systems will likely show up after the warranty expires, perhaps for the second or third owner. The biggest problem with this level of complication is rubber, namely the rubber flex hoses used to route coolant and fluids around the engine compartment to their various components. These rubber components have only so much lifespan regardless of how much or little you drive. It is the biggest problem with an older car, at least from my experience. With an old car from the 60′s or early 70′s, you could replace the radiator hoses and heater hoses, and perhaps the power steering lines and be done with it. Now there are so many lines on a modern car, that’s very expensive and difficult to do. My 2000 Saturn L, has 3 water pumps. One on the engine, a second electric pump to circulate coolant through the radiator (and motor) after shutdown to help cool a super heated engine, and a third to circulate coolant through the heater core to get heat to the cabin faster (before the thermostat opens). Keep in mind this is a 10 year old car! God knows how messy complicated a typical 2010 car is, let alone the Volt.


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    Dec 9th, 2010 (12:09 pm)

    We have the electric drive… the next task is to get rid of the ICE! Many options here…can’t wait to see what shows up the next few years to replace the ICE in the Volt technology.


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    Dec 9th, 2010 (12:19 pm)

    neutron: Experience has proved to me that the KISS (Keep It Simple Student {or stupid}) technique is usually the better solution.

    #44

    Yeah, that was my thought too. So much for KISS, LOL. +1

    Great job WOT. Thanks.


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    Dec 9th, 2010 (12:24 pm)

    Mark Z: Is the 360V heating element turned on to keep the high voltage cells above freezing when the Volt high voltage battery has available SOC and the vehicle is turned OFF and parked outside in below freezing weather?

    For this question, I needed to add, this would be with the Volt unplugged.

    There is a sentence in the December 2010 GM TechLink Magazine referring to the high voltage battery active liquid cooling system that answers the question IF the vehicle is plugged in:

    “It is designed to provide reliable battery operation when plugged in, at temperatures as low as -13° F (-25° C) and as high as 122° F (+50° C), and can be powered during driving either by the battery or the engine.”

    Note: That’s negative 13 degrees Fahrenheit. Plug it in, plug it in.

    One possible answer for an unplugged Volt is found in the Volt Owner Manual on page 10-25. 14° F (above zero) and 95° is the temperature range for extended storage. SOC should be at 50% with the 12 volt battery disconnected or on a trickle charger. “Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”


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    Dec 9th, 2010 (12:34 pm)

    jim1961: Heat pumps become inefficient at low temperatures. Extreme low temperatures is when the battery would be in most need of being heated.

    The amount of heat needed by the battery is very small so a heat pump isn’t worth it. The battery is insulated so it would lose heat slowly.

    The heat pump would make a lot of sense for the cabin heat. It could use the motor and inverter waste heat as its heat source.


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    Dec 9th, 2010 (12:42 pm)

    The part I really don’t understand is not mixing the battery and electronics cooling loops. They have similar requirements and use the same fluid. They could use the same reservoir and radiator, just with separate 12V pumps.

    When the battery is in heating or chiller mode it is isolated from the radiator so the electronics cooling wouldn’t mess with it.


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    Dec 9th, 2010 (12:48 pm)

    The 4ET50 drive unit utilizes a system of pressurized automatic transmission fluid (Dexron VI®) that is used to :

    - create fluid pressure to apply 3 multi-disc clutches and input damper clutch
    - lubricate all gears, bearings and bushings
    - cool the motor generator units (MGA & MGB) and other components

    The necessary pressure is primarily created by a 3-phase A.C. electrical motor/pump assembly within the transaxle. There is also a more conventional mechanically driven gear pump to insure transmission fluid pressures and flow are always present when the internal combustion engine is running.    

    Three phase AC driven pump? That will seriously frustrate any attempts to use the Volt as towed car behind an RV. If it was DC driven it could simply be powered from the RV.


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    Dec 9th, 2010 (12:49 pm)

    CaptJackSparrow: A.D.D. kicked in @ “within the 4ET50E drive unit transaxle……”

    Isn’t that A.A.A.D.D.? …………………………………………… Age Accelerated Attention Deficit Disorder? ;-)


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    Dec 9th, 2010 (12:54 pm)

    Raymondjram: James, You are correct in stating the importance of keeping oneself educated to understand any technology, especially something as the Chevy Volt, and I give you the Helm Inc web page to order the Volt Service Manual Set:http://www.helminc.com/helm/Result.asp?Style=helm&Mfg=GMC&Make=CHV&Model=VOLT&Year=2011&Category=&Keyword=&Module=&selected%5Fmedia=)”>(Reply)

    Those manuals will be a must-have for any Volt owner, to be sure!

    A TV news outlet here did a consumer expose where they took a three year old Honda Accord to a certified ASE mechanic and had it gone over with a fine-toothed comb, then handed it to one of their female news staffers to go to 8 different auto shops to have it looked over.
    The average estimate out of 8 shops was $290.00!!! One shop told her they’d need the car for a couple of days and quoted her $1200.00 for various things they’d need to fix/replace! Only one shop was totally honest, telling her the car needed absolutely nothing, and one quoted her for an oil change.

    Lessons here? Auto mechanics are like used car salesmen – or maybe doctors! Be careful! Always get a second or third opinion – and IF YOU’RE A WOMAN – be extra mindful. The best advice is to educate yourself so you know at least the basic vocabulary, but better, everyone regardless of sex should buy a mechanical manual for their particular vehicle. Statistics show you get a completely different response from an auto mechanic if you at least know basic particulars about CV joints, transmission parts, etc.. Women really should take a man along with them to get estimates on mechanical work. Same with car purchases. We’ve all heard the nightmarish stories from women who go it alone while buying a car – even ones who buy from women salespeople!

    PUMP OUT THE VOLTS! ,

    James


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    Derek Taubert

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    Dec 9th, 2010 (12:54 pm)

    wizland: Rashiid Amul,
    When servicing my car I prefer to have options.I’m not happy with being told I have to buy anything exclusively from the dealer.I planned on getting my Volt serviced by the dealer because it is such new technology, but I don’t like someone telling me I have to.    

    Dexcool and Dexron VI can both be purchased at local auto parts stores, FWIW. Kmart even sells the stuff…

    Derek


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    DonC

     

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    Dec 9th, 2010 (12:56 pm)

    We’ve known that the Volts are being delayed pending ‘Final Quality Check”. Today a friend told me that the problem is with the power supply to the dash. Has anyone else heard about this?


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    Streetlight

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    Dec 9th, 2010 (1:03 pm)

    This shows how critical GM EV training is to VOLT’s success. And the difficulty of putting together the training program to start with. Here we have multiple core (32 bit) cpu’s with millions of lines of code, AC-DC fundamentals, hi & lo power electronics, and temp control basics. Any of these being a full course itself. (I would suggest to any EV tech student WOT’s article needs to be carefully studied.)

    I know the details here all looks complicated but nonetheless essential. For example, in my own product development field it was the like copious attention to detail as the diff between our flagship product (c.1987) being deadnuts accurate and reliable and my competitions’ piece of crap. When my competitors visited our plant they were shocked at the extensive testing facilities and attention given to each component. (Electronics and chemistry)

    An outstanding work. Thanks WOT!!!!!


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    Dec 9th, 2010 (1:21 pm)

    Derek Taubert: Dexcool and Dexron VI can both be purchased at local auto parts stores, FWIW. Kmart even sells the stuff…

    Just make sure to use DI water if it isn’t already pre-mixed.


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    Nelson

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    Dec 9th, 2010 (1:34 pm)

    The Bugatti Veyron has a total of ten radiators.

    3 heat exchangers for the air-to-liquid intercoolers.
    3 engine radiators.
    1 for the air conditioning system.
    1 transmission oil radiator.
    1 differential oil radiator.
    1 engine oil radiator.

    Bugatti-Veyron-Super-Sport-20.jpg

    NPNS!


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    Rashiid Amul

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    Dec 9th, 2010 (1:58 pm)

    Mitch:
    As I work for a manufacturer (not automotive but we have specific fluids for some high tech items), sometimes there are very specific reasons for this. Primarily, they tested it and it works, they are not about to test EVERY possible fluid, generally it is up to the alternate manufacturer to test it and prove = to OEM spec, then a manufacturer has to simply review the testing data and say yea or nay…..yes the coolant may cost more, but what if you do what you want, and there isa failure…you WILL have invalidated your warranty by not using what they require. How often are you required to change it? My equinox says change every 5 years, or x mileslook at it this way, say the special stuff is 800 bucks for a complete change, every 2 years, that is 1600 bucks in maintenance over the battery warranty…but you use the green stuff after the fist change because it is only 50 bucks…then the battery fails…GM sees the green stuff, you invalidated your warranty, that’ll be 10,000 bucks to fix your car + Labour, plus a flush and fill of the coolant, plus tax…1600 bucks looks pretty good.(all numbers are random ones pulled out of my….and should not be construed as remotely accurate, but are only used to generate a “you get the idea” scenario)    

    Mitch, I see your point and totally concur.

    +1 to you.


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    lousloot

     

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    Dec 9th, 2010 (2:06 pm)

    Wow, thanks! I didn’t realize that the Volt had 2 MG units, i thought the primary motor was tuned for output only. I suppose 4 loops isn’t that bad — You want to cool gear/trans with something slippery, but don’t need slippery stuff to cool bat/electronics. Sharing would have been nice.

    The biggest downside for me is: “*Warning* Due to potential issues with high-voltage safety, the Chevy Volt’s engine cooling, heater, power electronics and battery cooling systems should only be serviced by a qualified factory-trained Volt technician.”

    Sorry, I like to be able to service my own car if I need/want to, or take it to my favorite (bud) mechanic. Hmm, they use the word should… not the standard “Will void your warranty” there may be hope yet!


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    mikeinatl.

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    Dec 9th, 2010 (2:14 pm)

    To GM-Volt.com readers,

    Thanks for all the “up” votes on my contribution at #4 above!

    To quote Kermitt the Frog (and possibly BP Petroleum ), “It ain’t easy being green”.

    Mikeinatl


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    Dec 9th, 2010 (2:16 pm)

    Matthew_B: The part I really don’t understand is not mixing the battery and electronics cooling loops. They have similar requirements and use the same fluid. They could use the same reservoir and radiator, just with separate 12V pumps.

    It seems like much of the concern stems from the possibility of high voltages being carried by the coolant itself. It does seem likely that fail-safe electrical isolation is at least possible, which could lead to only three coolant loops isolated solely by type of coolant required. I hope they are working on this “back in the lab” for later versions.

    .


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    Dec 9th, 2010 (2:28 pm)

    Matthew_B,

    Wouldn’t you always want to tow it with the front wheels off the ground? I think the main traction motor is always engaged.


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    JEC

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    Dec 9th, 2010 (2:34 pm)

    Well, I guess the simplicity of the Volt transmission design did not make it to the thermal management team.

    Way to many opportunities for failure.


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    Dec 9th, 2010 (2:39 pm)

    Mark Z: “Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”

    Makes you wonder how they’ll be sold in the north… since inventory sitting out in dealer’s lot is the norm for mainstream vehicles.


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    Dec 9th, 2010 (2:40 pm)

    James: Hey Lyle,

    What did you do differently on 11/28 and 12/08 ( 30.8; 30.6 EV miles ), was it a really cold day? Did you not plug in at work? Did you race home – or take the Volt to the drags? L :) L

    Just curious.

    James

    I’ve noted still other variations, James. I think the answer lies in the fact that Lyle has a somewhat unpredictable schedule because 1) one of his many patients may need unexpected care at an area hospital, 2) his office hours for “out patients” may change from time to time if/when he may be asked to assist his colleagues, 3) his office hours and hospital “walk-around” hours are necessarily flexible because of varying patient needs, etc, etc. Our busy host doesn’t have a typical 9-5 job. As a result, these variables can easily result in his Volt’s charging time varying widely from day-to-day.

    /Lyle, my apologies, but I have friends who are MDs who typically have unpredictable schedules
    .


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    Dec 9th, 2010 (2:43 pm)

    Jackson,

    I don’t think they are saying there isn’t a fail safe. But if I’m trying to work on this thing at home without the proper manuals I might want to heed the warning. I would imagine the shop manual has you insure power flow has been disabled prior to services it.


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    Dec 9th, 2010 (2:44 pm)

    I’ve got some more information from the mailing list. Hamtramck has built about 400 Volts. They’re sitting in the parking lot. The first ones have been there for about a month. They are all awaiting a minor change for a display power supply. AAARRRRGGGGGG! We want our Volts! LOL

    The good news is that they charged daily.


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    Dec 9th, 2010 (2:46 pm)

    john1701a: Makes you wonder how they’ll be sold in the north… since inventory sitting out in dealer’s lot is the norm for mainstream vehicles. 

    Not an issue. Sitting out even in the most extreme cold won’t hurt the battery. Just plug it in and it will be as good as new. Extreme heat is a different proposition.


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    Dec 9th, 2010 (2:55 pm)

    Ted in Fort Myers:

    OT Just got permission to plug in at work from the highest level of management. They will charge me $0.60/day for what ever portion I need to fill up. Not a bad deal considering they are making people take unpaid days off, cutting back on holiday pay, eliminated overtime, raised the cost on healthcare before and when used. I cannot wait to take delivery of my Volt.

    Take Care, TED

    My compliments on striking a really good deal, Ted! Now you’ll have the option of arriving at work (rather than home) with a low battery and letting your employer provide most of your “fuel” to get to & from the office. It’s almost like being chauffeured to/from the office in a company-provided car. But YOU’LL get to have the fun driving! ;) ;) ;)


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    Dec 9th, 2010 (3:04 pm)

    (click to show comment)


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    Dec 9th, 2010 (3:15 pm)

    solo: The biggest problem with this level of complication is rubber, namely the rubber flex hoses used to route coolant and fluids around the engine compartment to their various components. These rubber components have only so much lifespan regardless of how much or little you drive.

    Depends on the quality of the rubber. In my VW, I didn’t change a single hose in 16 years and only one strap which was just starting to wear but I wanted to be on the safe side. My wife’s car, also a VW, has 18 years and all the hoses are original.

    If the engineering was done well, rubber items shouldn’t be a problem in the Volt. Especially the battery cooling system that they must have very carefully overdesigned.


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    Dec 9th, 2010 (3:26 pm)

    DonC: Volts are being delayed pending ‘Final Quality Check”. Today a friend told me that the problem is with the power supply to the dash.

    The new GM. They will not let the Volt go out the door if they know something is wrong and they need to fix it.

    That’s actually good news. GM’s reputation is in the balance and they do what has to be done. What’s a few more days of waiting ?


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    Dec 9th, 2010 (3:30 pm)

    As an engineer that worked on the cooling loops on the Space Shuttle, I can honestly say the Volt’s systems are comparable. It is a nice piece of engineering if I do say so myself.


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    bookdabook

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    Dec 9th, 2010 (3:37 pm)

    nasaman: Ted in Fort Myers:
    OT Just got permission to plug in at work from the highest level of management. They will charge me $0.60/day for what ever portion I need to fill up. Not a bad deal considering they are making people take unpaid days off, cutting back on holiday pay, eliminated overtime, raised the cost on healthcare before and when used. I cannot wait to take delivery of my Volt.
    Take Care, TED My compliments on striking a really good deal, Ted! Now you’ll have the option of arriving at work (rather than home) with a low battery and letting your employer provide most of your “fuel” to get to & from the office.

    I am attempting to establish a similar scenario with my Co.s facility mgr. He is cautious and wants me to sign a waiver protecting them in case something weird happens to their power supply which damages the Volt electronics. Does anyone know if the Volt comes with some kind of surge protection or other mechanism to protect it should something happen with the power output?


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    Dec 9th, 2010 (4:06 pm)

    Rashiid Amul: Mitch, I see your point and totally concur. +1 to you.  (Quote)  (Reply)

    Thank you Rashiid….


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    bitguru

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    Dec 9th, 2010 (4:08 pm)

    ccombs: the problem might be not being able to extract battery heat

    Alex Besogonov: Also, ability to reuse battery heat to heat passengers should be nice.

    I’m not sure I understand these comments. The battery won’t have much heat when it’s cold outside, right? (Maybe a little on long drives, but will there be enough heat to make it worth it? It’s not like the ICE, which generates heat like crazy via controlled explosions.) The battery will have some heat when it’s hot outside, but in that case there will be no demand to heat the passengers.

    George S. Bower: It looks like the schematic just posted shows that the battery heat transfer loop never uses ICE waste heat. wouldn’t this be a better source off “free” heat.—–or am I missing something.    

    Well most of the time the ICE will not be in use, right? If you have been driving for a while and kick in to Charge Sustaining mode, the battery will already have been heated electrically. So this would only help when the vehicle has been parked for a while, without being plugged in, with a depleted battery, in cold weather. Is this worth it or not?

    Some people are decrying the complexity here, but I’m not sure I agree. By designing four fully independent loops, GM has managed to keep each one at least somewhat simple.


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    Dec 9th, 2010 (4:26 pm)

    MichaelH: Isn’t that A.A.A.D.D.? …………………………………………… Age Accelerated Attention Deficit Disorder?

    AHAHAHAHAHAHAHAHAAA!!!!

    Yeah, age definitely is a big part of it. But theirs another “A” missing for Alcohol….lol :-P


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    Dec 9th, 2010 (4:48 pm)

    I don’t think this design is particularly complicated. If you merged some of the loops into one, you wouldn’t save any hose or pipe connections. All the same components need to be cooled. All you might save would be pumps and regulators. You’d have to remove versions that are optimized for one function with ones that serve double duty and compromise on performance.

    Putting in air cooling is usually preferred if you can do it. Since these components are liquid cooled, I have to assume they need to be.


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    DonC

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    Dec 9th, 2010 (4:54 pm)

    john1701a: Volt Owner Manual says otherwise

    You’re probably misreading or misunderstanding it. If you give a more precise quote we’d have something to work with. “Volt Owner Manual” is a bit vague.


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    Dec 9th, 2010 (5:02 pm)

    12 radiators for the Bugatti Veyron, 4 (partitions) radiators for Volt and the poster who mentioned 12 electric motors in his ’89 Trans Am. Computers – strings and strings of code, oh the software!…

    The uber complexities of today’s cars brings me back to square one. Instead of spending $35,000 for a EREV/hybrid, when will someone take a very aerodynamic platform ( commuter – 1st gen Honda Insight, Geo Metro , all-purpose – perhaps a 2 generations-back Accord ), and instead spend the money on the battery and motor. No frills, no power everything, no computers – megabuck cooling systems – just the basics. Possible tear out the seats ( one of the heaviest components of cars besides the engine and tranny ) and replace them with carbon fiber framed units, add a carbon fiber hood…There’s just tons of places on an EV to spend money besides all the bells and whistles. Pack a big li ion, lipo or LifePo battery in a stripped down chassis and get a full EV 200+ mpg… If the only reason why we haven’t seen such an experiment – and the full EV Tesla Model S will go there for $80K….which is rediculous, is that the price of the battery is the catch…Why won’t somebody prove this out – that we can have a practical EV without the need for an ICE for quite a bit less money than a Volt. We’ve wondered out loud many times how far a BEV Volt would go-especially with a larger pack yet it will still be burdened by the weight of so many complex cooling systems and gadgets.

    Check out the Avion for inspiration – it got 103 mpg twenty-four years ago without an electric motor! Today the same car got 119 mpg – with a small turbo diesel. http://www.100mpgplus.com/index.html

    http://www.evworld.com/article.cfm?storyid=1887
    Look what a guy in my area did with LEAD ACID batteries – 200 miles AER :

    http://www.ecofriend.org/entry/diy-electric-car-runs-200-miles-on-old-lead-acid-batteries/http://www.100mpgplus.com/

    The Avion ( pulled out of Automotive X-Prize because they wanted a $5000 entrance fee, the rules favored EVs and they required $4 million insurance policy plus room and board for all the participants on the road drive – they just couldn’t afford it.

    * I was going to post pictures – but nice how Google Images won’t let you post images from a URL: anmore – anyone got any tips from the new format?

    PUMP OUT THE VOLTS!

    James


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    Dec 9th, 2010 (5:07 pm)

    bookdabook:
    I am attempting to establish a similar scenario with my Co.s facility mgr. He is cautious and wants me to sign a waiver protecting them in case something weird happens to their power supply which damages the Volt electronics. Does anyone know if the Volt comes with some kind of surge protection or other mechanism to protect it should something happen with the power output?    

    It’s funny how risk management from Insurance Companies has come into play the last few years. We can’t play soccer at lunch on company property as of 5 years ago. Someone might get hurt and sue. I can see companies balking at providing power without some sort of enforcible waiver. Last thing they want is $10,000 claim for battery and maybe even higher for fried electronics. Look what happened to Neil Young’s converted EREV. The hook-up for the power supply caused a fire that destroyed the car and started the warehouse where it was stored on fire. Risk Managers see a story like this and get nervous, even if they shouldn’t.


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    john1701a

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    Dec 9th, 2010 (5:11 pm)

    (click to show comment)


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    Dec 9th, 2010 (5:59 pm)

    theflew: Matthew_B,
    Wouldn’t you always want to tow it with the front wheels off the ground?I think the main traction motor is always engaged.    

    It is an induction motor. Rolling it over does nothing except splash some oil around.


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    Dec 9th, 2010 (6:13 pm)

    Matthew_B:
    It is an induction motor.Rolling it over does nothing except splash some oil around.    

    Without cooling running, there could be problems. Towing Volt with all 4 wheels on the ground would void the warranty not to mention possibly destroy some expensive parts.


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    Stas Peterson

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    Dec 9th, 2010 (6:14 pm)

    By comparison, the Leaf’s cooling sysytem is primitive and under-engineered indeed…


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    Dec 9th, 2010 (6:16 pm)

    john1701a:
    I already did.Here it is again…“Vehicle storage at extreme temperatures can cause damage to the high voltage battery.

    Parking and storage are two different things.


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    nasaman

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    Dec 9th, 2010 (6:17 pm)

    john1701a: “Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”

    Notice no mention of hot or cold. Of course, we already know that lithium requires warming with any temperature below freezing and the engine will warm it to room temperature (70′ish) for normal operation. Here in Minnesota, temperatures much colder are normal all throughout the winter.

    One of my specialties in the space program has been the design of long-life (15-20 yr) batteries that can operate in the extremely harsh +/-300F temperatures of space. Because of that background, I’ve paid close attention to the thermal design challenges GM has had with the Volt battery and I clearly recall (sorry, can’t give you a link) that the Volt battery can “soak” indefinitely at extremely cold temps (i.e., on the order of -40 deg C/F) without damage. The important requirement is that the thermal control subsystem will raise the battery operating temperature to its normal operating range within a reasonable time —and that the rate of temperature increase is sufficient to assure both the battery’s performance and its longevity. It’s not a problem with the current Volt design.
    .


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    john1701a

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    Dec 9th, 2010 (6:21 pm)

    (click to show comment)


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    Raymondjram

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    Dec 9th, 2010 (6:24 pm)

    john1701a:
    I already did.Here it is again…“Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”Notice no mention of hot or cold.Of course, we already know that lithium requires warming with any temperature below freezing and the engine will warm it to room temperature (70′ish) for normal operation.Here in Minnesota, temperatures much colder are normal all throughout the winter.    

    Chevrolet has finally posted the Volt Owner Manual as a PDF. here is the direct link:
    http://www.chevrolet.com/assets/pdf/owners/manuals/2011/2011_chevrolet_volt_owners.pdf

    Now everyone here can download, read, and comment on the Volt operation and user servicing without paying the $25 + $15 S/H to helm Inc.

    On page 9-25 there is a mention on the electric mode operation under extreme cold temperatures:
    “In Electric Mode, the vehicle does not use fuel or produce tailpipe emissions. During this primary mode, the vehicle is powered by electrical energy stored in the high voltage battery. The vehicle can operate in this mode until the battery has reached a low charge.
    There are some conditions when the battery charge is high enough to provide Electric Mode operation, but the engine still runs. They are:
    . Cold ambient temperatures.
    . Hot or cold high voltage battery
    temperatures.”

    I believe this what some here are asking.

    Raymond


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    Baltimore17

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    Dec 9th, 2010 (6:27 pm)

    neutron: Did I read correctly there is at least 2 different kinds of coolant on the the systems. What happens if they get mixed up?

    Yeah, but the two are equivalent to the radiator coolant and transmission fluid that everyone knows and loves in conventional cars. “Hon, I think I just poured transmission fluid into the radiator” isn’t a statement I’d ever expect to hear :-)


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    Dec 9th, 2010 (6:31 pm)

    Raymondjram:
    Chevrolet has finally posted the Volt Owner Manual as a PDF. here is the direct link:
    http://www.chevrolet.com/assets/pdf/owners/manuals/2011/2011_chevrolet_volt_owners.pdfNow everyone here can download, read, and comment on the Volt operation and user servicing without paying the $25 + $15 S/H to helm Inc.Raymond    

    Oh well, my forty bucks got me three weeks of advance reading.


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    Dec 9th, 2010 (6:32 pm)

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    MichaelH

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    Dec 9th, 2010 (6:34 pm)

    john1701a: Please provide a duration for each which depicts the difference.

    Do not allow the vehicle to remain in temperature extremes for long periods without being driven or plugged in. It is recommended that the vehicle be plugged in when temperatures are below 0°C (32°F) and above 32°C (90°F) to maximize high voltage battery life.

    I sent in the question to GM as to the definition of long periods, haven’t gotten an answer yet.


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    Dec 9th, 2010 (6:38 pm)

    Loboc:
    Without cooling running, there could be problems. Towing Volt with all 4 wheels on the ground would void the warranty not to mention possibly destroy some expensive parts.    

    I believe that the Volt owner’s manual says exactly that. I was surprised because the first generation Saturn, the small series, was specifically designed to allow flat (4 wheels on ground) towing. Maybe that was the automotive engineering high point where towing is concerned.


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    kent beuchert

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    Dec 9th, 2010 (6:39 pm)

    Perhaps this gives you a taste of what I consider the Volt’s biggest defect – an overly complicated (and therefore overly expensive) architecture. This is an overly-engineered beast that guarantees GM Goodwrench shop work for its lifespan. And they say electric cars have a simple, reliable and elegant design. Well, they do ……
    As Henry Ford used to say : “I can sell Model T’s for a penny and still make a profit.” Off the replacement parts and labor required.


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    Dec 9th, 2010 (6:47 pm)

    MichaelH: I sent in the question to GM as to the definition of long periods, haven’t gotten an answer yet.

    That’s very much appreciated.

    Tomorrow’s low is predicted to be -11°F (-24°C). So as far as anyone here is concerned, just overnight is a horribly long time to be outside in that.


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    Dec 9th, 2010 (6:49 pm)

    john1701a:
    That’s very much appreciated.Tomorrow’s low is predicted to be -11°F (-24°C).So as far as anyone here is concerned, just overnight is a horribly long time to be outside in that.    

    From Mark Z:
    “In doing searches on the web and the owner manual, extended storage requires the removal of the negative 12 volt battery cable, having the high voltage battery SOC at 50% and storing between 14 degrees F and 95 degrees F.”

    People have been discussing this in several threads in the Forum for several days.


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    Baltimore17

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    Dec 9th, 2010 (6:59 pm)

    James: Instead of spending $35,000 for a EREV/hybrid, when will someone take a very aerodynamic platform ( commuter – 1st gen Honda Insight, Geo Metro , all-purpose – perhaps a 2 generations-back Accord ), and instead spend the money on the battery and motor. No frills, no power everything, no computers – megabuck cooling systems – just the basics.

    This sounds equivalent to someone making a plea to knock all the frills and complexity out of the Corvette to get blinding performance at a much lower price with better economy.

    In my garage, one of my two vehicles has published 0-60 mph numbers equivalent to the last generation Z06 Corvette, has a published top speed of 132 MPH, and gets (by my actual experience) 54 miles per gallon. It’s a Suzuki SV-650 V-twin sport bike and, sure, it cost 10% of a Z06 but is in no way a practical equivalent to a sports car.

    I certainly don’t want a stripped-down Volt with an unprotected battery, coarsely-controlled acceleration and braking even more uneven than that reported for conventional hybrids. No computers? My house thermostat has a computer in it for heavens sake! They’re not exotic, scary, expensive, fragile unknowns anymore, not for three decades in cars at least.


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    MichaelH

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    Dec 9th, 2010 (7:24 pm)

    Baltimore17: “Hon, I think I just poured transmission fluid into the radiator” isn’t a statement I’d ever expect to hear.

    The owners manual doesn’t list the electric-drive unit cooling system under Vehicle Care or Service and Maintenance. It only lists the fluid spec in the Tech specs. The under the hood figure does not show the location to check the electric-drive unit cooling system, much less to add to it. I’d say one would be pretty safe to just worry about the other three systems with one fluid spec – Dexcool. Not much chance of mixup. :-)


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    theflew

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    Dec 9th, 2010 (7:29 pm)

    kent beuchert: Perhaps this gives you a taste of what I consider the Volt’s biggest defect – an overly complicated (and therefore overly expensive) architecture. This is an overly-engineeredbeast that guarantees GMGoodwrench shop work for its lifespan. And they say electric cars have a simple, reliable and elegant design. Well, they do ……
    As Henry Ford used to say : “I can sell Model T’s for a penny and still make a profit.”Off the replacement parts and labor required.    

    The Volt is complex. Anyone that thought having and ICE/generator and electric motors was going to be simple knows nothing about engineering. If graphed complexity the Volt would be the highest followed by Tesla than at the bottom would be the Leaf. The Leaf has a simple system that might or might not pan out especially in hot/cold climates. The heater option isn’t even available for the Leaf this model year and can’t be added to the first generation that’s out now. Seems like they are releasing the car before it was completely finished.

    This board has lite up like a Christmas tree over the heating/cooling system, but everyone just excepts the complexity of the motor/generator, embedded planetary gear set and clutches. That’s why they applied for a patent, because it’s complex. Not for the hoses, pumps and valves which are pretty ordinary. There is just more of them because the car operates in multiple modes. We’re talking about pumps and valves not exactly space age technology here.


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    Dec 9th, 2010 (7:37 pm)

    Mark Z:
    There is a sentence in the December 2010 GM TechLink Magazine referring to the high voltage battery active liquid cooling system that answers the question IF the vehicle is plugged in:“It is designed to provide reliable battery operation when plugged in, at temperatures as low as -13° F (-25° C) and as high as 122° F (+50° C), and can be powered during driving either by the battery or the engine.”Note: That’s negative 13 degrees Fahrenheit. Plug it in, plug it in.One possible answer for an unplugged Volt is found in the Volt Owner Manual on page 10-25. 14° F (above zero) and 95° is the temperature range for extended storage. SOC should be at 50% with the 12 volt battery disconnected or on a trickle charger. “Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”    

    For those who didn’t read the whole thread today, the above text was from post 71. Having a Volt sitting outside in Detroit got me started asking questions in the forum days ago. If all the instructions are correct, then the summary for high voltage battery health is:

    While plugged in, battery is safe from -13F to +122F.
    Not plugged in and at 50% SOC, battery is safe from +14F to +95F.

    With all the info on the web about not freezing lithium ion batteries, I’ll sleep better when my Volt is parked in the garage with a charge cord attached.


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    Cab Driver

     

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    Dec 9th, 2010 (7:45 pm)

    Matthew_B: The part I really don’t understand is not mixing the battery and electronics cooling loops. They have similar requirements and use the same fluid. They could use the same reservoir and radiator, just with separate 12V pumps. When the battery is in heating or chiller mode it is isolated from the radiator so the electronics cooling wouldn’t mess with it.  (Quote)  (Reply)

    If I understand correctly, the battery and electronics need separate cooling systems because the temperature setpoints are quite different. The battery likes to stay at about 75 degrees F and the power electronics can run ok at up to about 125 degrees F. Sharing the coolant would not work out.


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    Dec 9th, 2010 (7:47 pm)

    Mark Z: One possible answer for an unplugged Volt is found in the Volt Owner Manual on page 10-25. 14° F (above zero) and 95° is the temperature range for extended storage.

    The “online manual” referenced today, has it on Page 10-29:
    Always store the vehicle in an environment between −10°C (14°F) and 30°C (86°F).
    New page, new upper limit.


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    DonC

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    Dec 9th, 2010 (7:58 pm)

    john1701a: Notice no mention of hot or cold. Of course, we already know that lithium requires warming with any temperature below freezing and the engine will warm it to room temperature (70′ish) for normal operation. Here in Minnesota, temperatures much colder are normal all throughout the winter.

    The battery isn’t going to be hurt by cold weather. Cold weather degrades performance but not life. In any event they are probably referring to extended storage, not about going on vacation for a couple of weeks. And certainly not “overnight” as you’re seemingly suggesting. You’re working very hard to create a problem where none exists. If you’re that worried about cold weather affecting battery life, then avoid the PIP at all costs. (For some reason I’m thinking that’s “different”).

    As a FYI the battery works perfectly well at 0 C so it’s “warmed” to this temperature not 70 F. But the fact of life is that batteries don’t perform well in very cold temperatures


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    kdawg

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    Dec 9th, 2010 (7:59 pm)

    john1701a: “Vehicle storage at extreme temperatures can cause damage to the high voltage battery.”
    Notice no mention of hot or cold. Of course, we already know that lithium requires warming with any temperature below freezing and the engine will warm it to room temperature (70′ish) for normal operation. Here in Minnesota, temperatures much colder are normal all throughout the winter.

    Maybe they will leave them plugged in. Like you would at home. I don’t know what you would do if you left it in an airport over 2 weeks, but I dont think that constitutes “a long time”.


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    Dec 9th, 2010 (8:07 pm)

    john1701a: vague responses are a play right out of the underminer’s handbook

    I learned that from watching john1701a and ericlg.


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    Dec 9th, 2010 (8:12 pm)

    MichaelH:
    The “online manual” referenced today, has it on Page 10-29:
    Always store the vehicle in an environment between −10°C (14°F) and 30°C (86°F).
    New page, new upper limit.    

    Excellent find Michael. At last the manual is online and that page number you reference is not the same in the printed manual, so the old printed one can go on the shelf

    Here is the link:

    http://www.chevrolet.com/assets/pdf/owners/manuals/2011/2011_chevrolet_volt_owners.pdf

    So to summarize and add some text to make it clear:

    While plugged in or while Volt is ON, battery is safe with outside temps of -13F to +122F.
    Not plugged in and at 1/2 charge or less, battery is safe with outside temps of +14F to +86F.


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    Dec 9th, 2010 (8:34 pm)

    rob: I think wejust found an area where future models can reduce costs.Holy over-complicated, Batman!    

    Or Holy-sufficiently complicated. We’ll know more in a few years.

    Be well and believe,
    Tagamet

    Let’s Just Get Enough VOLTS ‘ Wheels On The Road!!


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    Jackson

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    Dec 9th, 2010 (8:39 pm)

    john1701a: Please provide a duration for each which depicts the difference.

    John, please provide a thorough explanation as to why you perpetually feel the need to show up here and make petulant demands. Use only words of 8 syllables. Well? Hop to it, @$$h0|3.

    john1701a: Sorry, but vague responses are a play right out of the underminer’s handbook.

    Well you ought to know; you’ve memorized it cover to cover. Do you sleep with it?

    Don’t the pages get groady?

    ~~~~~~~~~~

    Don’t bother to reply, folks; just vote him down. Trying to talk to the Priinut is a waste of electrons (as I ought to know).

    .


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    Dec 9th, 2010 (8:46 pm)

    Mark Z: Here is the link:
    http://www.chevrolet.com/assets/pdf/owners/manuals/2011/2011_chevrolet_volt_owners.pdf

    While the links work on the computer, the GM web site puts the iPad user on a non-flash web page. The result is the manual is not downloading as normal .PDF files do. Even using GoodReader creates the non-flash page instead of the manual. GM needs to work on their site for iPad and iPhone users. An alternative will be to save the .PDF to the computer and transfer manually to the iPad.


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    Dec 9th, 2010 (9:07 pm)

    Hey WOT,

    Great article.

    I would like the following questions answered for 2 scenarios:
    1. Volt off and plugged in
    2. Volt off and not plugged in

    The questions:
    1. At approximately what SOC and temperature will the Volt start to cool the battery? (Or will this never happen?)
    2. At approximately what SOC and temperature will the Volt start to heat the battery? (Or will this never happen?)

    So, I’m looking for 4 answers. Each answer will have an SOC and a temperature.


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    Dec 9th, 2010 (9:16 pm)

    And while things are getting a bit hot around here, why not show some of the text from the new Volt FAQ that has appeared on the GM website. http://www.chevrolet.com/volt/

    Quoting from the Battery Life section:

    Here are a few tips to help you maximize the life of your battery:

    - It is recommended that the vehicle be plugged-in when ambient temperatures are below 32°F (0°C) and above 90°F (32°C).

    - It is preferable to park out of direct sunlight to help stabilize any environmental affects. This is
    particularly important in very hot climates.

    - If long term, unplugged storage is required, store the vehicle with ½ (50%) charge or less and always store it in an environment with temperatures between 15°F (-10°C) and 85°F (30°C). Like any vehicle the 12V battery may need to be supported during extended periods without driving. See the owner manual for how to keep the 12V battery from running down during extended storage.

    End Quote.

    Why 15°F and 85°F on the FAQ instead of 14°F and 86°F in the manual? The person who wrote the FAQ used a bad calculator to convert the Celsius to Fahrenheit. 14°F and 86°F is correct.


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    Dec 9th, 2010 (9:23 pm)

    Mark Z: The person who wrote the FAQ used a bad calculator to convert the Celsius to Fahrenheit. 14°F and 86°F is correct.

    That’s also the reason for the difference between the printed manual, page 10-25 and the online manual, page 10-29. They both say 30 C. The difference between 95 F and 86 F, is the calculator. :-)


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    Dec 9th, 2010 (9:27 pm)

    Mark Z: Why 15°F and 85°F on the FAQ instead of 14°F and 86°F in the manual? The person who wrote the FAQ used a bad calculator to convert the Celsius to Fahrenheit. 14°F and 86°F is correct.

    The manuals are written well ahead of the car’s final tweaks. Plus, it’s not a biggie to be off by one degree. I’m sure when some of the ADD among us compare the PDF vs the printed manual we will see a few (trivial) differences.


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    Dec 9th, 2010 (9:59 pm)

    Baltimore17: This sounds equivalent to someone making a plea to knock all the frills and complexity out of the Corvette to get blinding performance at a much lower price with better economy. In my garage, one of my two vehicles has published 0-60 mph numbers equivalent to the last generation Z06 Corvette, has a published top speed of 132 MPH, and gets (by my actual experience) 54 miles per gallon. It’s a Suzuki SV-650 V-twin sport bike and, sure, it cost 10% of a Z06 but is in no way a practical equivalent to a sports car. I certainly don’t want a stripped-down Volt with an unprotected battery, coarsely-controlled acceleration and braking even more uneven than that reported for conventional hybrids. No computers? My house thermostat has a computer in it for heavens sake! They’re not exotic, scary, expensive, fragile unknowns anymore, not for three decades in cars at least.  (Quote)  (Reply)

    Maybe you just don’t understand where I’m coming from. Prius was the benchmark for Volt, and Volt fulfilled Bob Lutz and John Laukner’s dream of leapfrogging it. That said, these cars are supercomputers compared to old ’70′s Texas Instrument calculators that most of us have in our garages. I wouldn’t say a comparison to a motorcycle is appropriate. What I’m talking about in the Avion ( Google it’s story ) is not near any comparison that makes sense to me.

    Avion shows that aero, light weight and smart design coupled with a small gas engine can show results equal to or greater than Volt in mileage results. It even did so in the mid eighties! How that relates to an exposed, two wheeled, dangerous vehicle with no operator protection at all – well – this leaves me clueless. There are projects ongoing that don’t have the corporate backing and government funding that Volt has that have shown simplicity and the “K.I.S.S.” philosophy can show great results. My point was not to slam the Volt or Prius but to inject some thought as to how future developments will mainly result in a lot more simplicity. For instance. the 3rd gen Prius’s ICE has no belts – everything is electrically driven, including the water pump. I’m sure GM will streamline the Volt’s systems in future versions – and this is what I was pointing out. Volt hangs luxuries and doo dads on itself with no option to buy a more basic model.

    I was pointing out that I haven’t seen projects where a larger battery pack has been added in lieu of an ICE or heavy components meant for luxury and convenience – where things like aero and lightness ruled.

    James


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    Dec 9th, 2010 (10:14 pm)

    I lost my wireless connection so was unable to finish or edit my last post.

    I noticed in SAE’s great publication describing Volt’s development, they noted some compromises were made. They listed GM’s choice of an all steel body as a compromise as was the choice of an off-the-shelf, relatively low tech ICE in lieu of a more sophisticated ( light-efficient ) genset. They mentioned these compromises where taken to reduce cost, and because of time constraints. This supports my point that simpler is better – not only more reliable, but faster to market. Remove some of the gimmickry luxury on Volt and add components that will increase it’s AER performance.

    Traditional performance cars have a plethora of aftermarket bits to be bought for large sums of money with the goal of making them faster, or handle better. “Performance” to me, includes efficiency and I can see GM offering “performance” parts or the aftermarket selling carbon fiber Volt hoods, more aero style wheels aluminum hatches, doors and quarter panels to reduce weight. Other ideas are lightweight composite seats and even Atkinson-cycle engine kits with direct injection.

    PUMP OUT THE VOLTS! ,

    James


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    Tagamet

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    Dec 9th, 2010 (10:21 pm)

    Mark Z: An alternative will be to save the .PDF to the computer and transfer manually to the iPad.

    I simply don’t *go* to the site that should remain unnamed (g), but copying the file to the Ipad works just fine.

    Be well and believe,
    Tagamet

    Let’s Just Get Enough VOLTS ‘ Wheels On The Road!!


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    Dec 9th, 2010 (10:37 pm)

    Tagamet: I simply don’t *go* to the site that should remain unnamed (g),

    Tag, the official site for the manual is now the Chevrolet dot com site:
    http://www.chevrolet.com/owners/chevy-manuals/
    I don’t think that’s the same as the site that . . .

    BTW, thanks for the card that came in the mail today. :-)


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    Dec 9th, 2010 (10:48 pm)

    MichaelH: Tagamet: I simply don’t *go* to the site that should remain unnamed (g),

    Tag, the official site for the manual is now the Chevrolet dot com site:
    http://www.chevrolet.com/owners/chevy-manuals/
    I don’t think that’s the same as the site that . . .

    BTW, thanks for the card that came in the mail today. :-)

    Tomato… Toe-mah-toe…

    Glad you got the card and the receptacle covers.
    OT, but extrtemely timely: How in the *WORLD* do folks on the Left Coast (and New Mexico) get into the Christmas spirit??? Isn’t it all warm and dry and stuff? Around here, the high temp was a brisk 30 F, and the mountains are snow covered.
    Inquiring minds want to know (lol).

    Be well and believe,
    Tagamet

    Let’s Just Get Enough VOLTS ‘ Wheels On The Road!!


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    Leafer

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    Dec 9th, 2010 (10:54 pm)

    (click to show comment)


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    Dec 9th, 2010 (11:06 pm)

    Tagamet: How in the *WORLD* do folks on the Left Coast (and New Mexico) get into the Christmas spirit??? Isn’t it all warm and dry and stuff? Around here, the high temp was a brisk 30 F, and the mountains are snow covered.
    Inquiring minds want to know (lol).

    Well, right now it’s a bit tough. We are having a La Nina (la neen-ya) winter. No snow and highs in the mid 50′s so far. It’s about 20 at night. We have seen snow on the mountains, but not much.

    Ordinarily we get several feet during the winter. (I have a snow blower and use it.) We live at 6400 feet and the main part of town is at 7000 feet. We even have our own ski hill on the west side of town at about 10,400 feet. Just north of here are many more, Toas, Red River, Angel Fire, Eagles Nest, etc. It helps to watch it on the news. Enough?


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    john1701a

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    Dec 9th, 2010 (11:11 pm)

    Jackson: please provide a thorough explanation as to why

    Some of us aren’t afraid to ask the difficult questions and are not deterred by childish insults. We’re well aware that consumers will want to know those answers. We also know that lithium chemistries & implementations differ.

    Seeing the minimum temperature mentioned in the Owner’s Manual (14°F) is well above the daily high we routinely experience here in Minnesota makes the question quite valid. I won’t be able to plug-in the entire time I’m at work. 9 hours of exposure to much colder conditions means what?

    People aren’t going to make such an expensive purchase without knowing. Getting an evasive response to asking will really make them wonder about that recommendation to plug-in whenever the temperature is below freezing. Why?


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    Dec 9th, 2010 (11:15 pm)

    Back to the manuals link, that is also the link to the warranty pdf file and a really neat set of GM produced “how to” videos for the Volt.


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    Dec 9th, 2010 (11:21 pm)

    john1701a: I won’t be able to plug-in the entire time I’m at work. 9 hours of exposure to much colder conditions means what?

    Here’s a partial answer:

    http://www.youtube.com/watch?v=6M-CSlcp06g&feature=player_embedded

    Heat degrades the battery, cold degrades performance (range).


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    Dec 9th, 2010 (11:23 pm)

    MichaelH,

    Then again, we all share the Christmas Trolls!

    Merry Voltmas,
    Tagamet


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    Dec 9th, 2010 (11:43 pm)

    Tagamet: Then again, we all share the Christmas Trolls!Merry Voltmas, Tagamet    

    I think they hide in with the elves. 8-)


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    Dec 9th, 2010 (11:56 pm)

    MichaelH: http://www.youtube.com/watch?v=6M-CSlcp06g&feature=player_embedded

    You’re right, an excellent video that helped me understand how GM is protecting the battery from the temperature extremes we have been discussing recently.

    For details on lithium-ion batteries and how to achieve maximum life span when not using them, this website has lots of revealing facts. This will help explain the why.

    http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

    By oversizing the battery and never allowing the battery to fully charge or discharge, GM is extending the life of the battery. They guarantee it. It is up to the dealer and purchaser to know what the temperature extremes the Volt is designed for and operate or store it within those parameters. If someone is considering a Volt and cannot plug in during the temperature extremes, then by all means purchase an ICE vehicle instead.


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    Dec 10th, 2010 (12:30 am)

    I’m out West in Seattle…We had temps in Western Washington under 20 degrees in late November, and a few days of snow! That’s unusual for here – on an average year we may have 1 or 2 days of snow, if that, all year. We get precipitation here, but as you know, usually as rain.

    I wouldn’t have driven my Volt on those days, and relied on the 4X4. It’ll be interesting to see how the folks in CT, NY and NJ do with their Volts this winter. I know efficiency goes down – our Prius goes from mid 40′s mileage and better in summer to 30′s to 36 in our moderate winter. It makes thermal mgmt. of the pack sound valid to me.

    PUMP OUT THE VOLTS! ,

    James


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    Dec 10th, 2010 (12:59 am)

    BREAKING: Revenge of the Electric Car trailer just released:
    http://www.youtube.com/watch?v=jkRIu5a6Sb0


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    Dec 10th, 2010 (2:02 am)

    Shaft: The questions:
    1. At approximately what SOC and temperature will the Volt start to cool the battery? (Or will this never happen?)
    2. At approximately what SOC and temperature will the Volt start to heat the battery? (Or will this never happen?)

    The battery is kept between 0F and 80F for all SOC when the car is operating.


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    Dec 10th, 2010 (2:07 am)

    john1701a: Some of us aren’t afraid to ask the difficult questions and are not deterred by childish insults. We’re well aware that consumers will want to know those answers. We also know that lithium chemistries & implementations differ.
    Seeing the minimum temperature mentioned in the Owner’s Manual (14°F) is well above the daily high we routinely experience here in Minnesota makes the question quite valid.

    This isn’t a “difficult question.” Another adjective might be more appropriate. You keep focusing on the temperature during extended storage. That has noting whatsoever to do with what you’re talking about unless you plan on leaving the country for a year and want to park your Volt outside till you get back. You can put the Volt outside in -50F and the battery will be just fine. You’re simply manufacturing an issue where none exists.


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    Dec 10th, 2010 (2:13 am)

    James: I know efficiency goes down – our Prius goes from mid 40’s mileage and better in summer to 30’s to 36 in our moderate winter.

    One reason the Prius MPG greatly suffers in cold weather is that the engine has to heat the cat converter and keep it heated whenever the car is turned on. In winter that means the engine can run continuously if you’re only going on a short trip. In these cases you’ll get single digit MPG. Reset the fuel economy gauge and check it out for yourself.


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    Dec 10th, 2010 (3:08 am)

    nasaman: BREAKING: Revenge of the Electric Car trailer just released:
    http://www.youtube.com/watch?v=jkRIu5a6Sb0    

    Thanks for the heads up on this. The premiere will bring out a lot of EV’s in the parking lot. Hopefully Lyle will get to attend along with many others who have been the force behind the four companies that are in the race to get electric cars back on the road again.


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    Dec 10th, 2010 (6:07 am)

    OT: Ten Reasons to be Excited About Electric Vehicles – A truly superb overview that I’m positive will be helpful as a link or as a handout to friends, family —or, in fact —anyone at all!*

    Click: http://www.pluginamerica.org/drivers-seat/ten-reasons-be-excited-about-electric-vehicles

    *Written by Tom Saxton, owner of a RAV4 EV & a Tesla Roadster for Plug In America
    .


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    Dec 10th, 2010 (6:16 am)

    Tagamet: OT, but extrtemely timely: How in the *WORLD* do folks on the Left Coast (and New Mexico) get into the Christmas spirit??? Isn’t it all warm and dry and stuff? Around here, the high temp was a brisk 30 F, and the mountains are snow covered.Inquiring minds want to know (lol).Be well and believe,TagametLet’s Just Get Enough VOLTS ‘ Wheels On The Road!!  (Quote)  (Reply)

    You forget that not everyone who lives on the Right Coast is getting cold weather. Here in Puerto Rico where we are more to the east (longitude 65.5 degrees) , we are having cool weather at our north coast (72 to 80 F) and some of out central towns and cities are colder (55 to 65 F). We have the ideal weather for the Chevy Volt all year long, but GM hasn’t allocated any Volts for us yet.

    Raymond


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    Jean-Charles Jacquemin

     

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    Dec 10th, 2010 (6:17 am)

    nasaman: BREAKING: Revenge of the Electric Car trailer just released:
    http://www.youtube.com/watch?v=jkRIu5a6Sb0    

    Many thanks Nasaman,
    They used Carl Orff music quite a lot …

    Best regards,

    JC NPNS


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    Eco_Turbo

     

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    Dec 10th, 2010 (6:38 am)

    # 158 nasaman said:

    OT: Ten Reasons to be Excited About Electric Vehicles

    A great read nasaman, thanks for the link. But I can’t help equating this with explaining how good crawfish etouffee is to someone who lives in Alaska. When electric cars cost the same as gas cars, everybody will find out for themselves. Until then, they will be like gourmet restaurants.


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    koz

     

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    Dec 10th, 2010 (7:25 am)

    25mpg car owner is buying a new car a desires to reduce gas consumption and is comparing Volt vs the next best non range limited vehicle. His driving situation is similar to Lyles.

    -Volt would reduce consumption to 1/6th of current or by 83%
    -The next best option reduces consumption to 1/2 of current or 50%

    On a national fleet consumption basis, one Volt in hand is worth 1.667 next best in the bush.


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    Chris C.

     

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    Dec 10th, 2010 (7:37 am)

    Lyle, I still think WOT’s missing image should be edited back into the article, as I said above. Is there a reason you aren’t posting it?


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    edvard

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    Dec 10th, 2010 (10:57 am)

    As someone who owns a Prius with its two seperate cooling systems, I am not a huge fan of having to change not one, but two coolant systems. The Volt has 4. Secondly, Dexcool is incredibly notorious for crudding up coolant passages as it ages- especially if it comes into contact with oxygen, which is bound to happen at some point.

    I also wonder if the coolant systems in the volt are going to be like those in the Prius in that you’d have to use a vacuum system to change the coolant since getting any air pockets in the loops would ruin the inverters, etc.


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    WopOnTour

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    Dec 10th, 2010 (12:06 pm)

    Sorry I wasnt able to get back here yesterday and deal with some of the questions.
    What I plan to do is repost the entire article into the forums so that I can hopefully address any of the questions some of you ight have on the Volt’s thermal managment systems.

    WopOnTour


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    WopOnTour

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    Dec 10th, 2010 (12:47 pm)

    edvard: As someone who owns a Prius with its two seperate cooling systems, I am not a huge fan of having to change not one, but two coolant systems. The Volt has 4. Secondly, Dexcool is incredibly notorious for crudding up coolant passages as it ages- especially if it comes into contact with oxygen, which is bound to happen at some point. I also wonder if the coolant systems in the volt are going to be like those in the Prius in that you’d have to use a vacuum system to change the coolant since getting any air pockets in the loops would ruin the inverters, etc.  (Quote)  (Reply)

    Edvard. Other than routinely checking and verifying the coolant levels, MOST of Volt’s cooling systems have ZERO scheduled maintenance. However the ICE coolant has a flush/fill recommendation after 5 years/100K miles. The A/C refrigerant and POE oils have a 10 year life-cycle in hybrids (due mostly to R134a loss and moisture intrusion) so the recommendation is to recover, flush,evacuate and recharge the Volt’s air-conditioning system every 10 years.

    As far a you comments regarding Dexcool, most of these “claims” have long sincebeen proven as being totally unfounded, however ANY contamination of the Dexcool coolant can contribute to corrosion, hence the warnings to prevent tap water, non Dexcool coolants or ANY aftermarket additives from being introduced into the system.

    And YES, the only recommended method for refilling a drained coolant system (fr whatever reason) on the Volt is via a vacuum fill tool that all GM dealers are equipped with.

    HTH
    WopOnTour


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    john1701a

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    Dec 10th, 2010 (12:58 pm)

    DonC: One reason the Prius MPG greatly suffers in cold weather is that the engine has to heat the cat converter and keep it heated whenever the car is turned on. In winter that means the engine can run continuously if you’re only going on a short trip. In these cases you’ll get single digit MPG. Reset the fuel economy gauge and check it out for yourself.

    Twisting the information in the Volt Owner’s Guide and now intentionally misleading about Prius. Stop wasting our time.

    I start out each morning pressing reset. The trip to the grocery store is just under 3 miles, resulting in MPG in the 30′s during the winter extremes… not even close to that claim. My latest tank with a variety of driving and temperatures into the single digits °F, the average measured at the pump was still 45 MPG.

    By the way, the reason for heating the cat is to achieve the PZEV emission-rating. For Volt to be that clean, it too will need heat for cleansing.


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    Evil Conservative

     

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    Dec 10th, 2010 (1:06 pm)

    Dave: fascinating?  (Quote)  (Reply)

    Come on guys ….. What do you need? A refresher course? It’s all ball bearings these days.
    -Gordon Liddy, Fletch


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    edvard

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    Dec 10th, 2010 (1:28 pm)

    WopOnTour,
    Given that I once used Dexcool in my Tacoma 10 years ago and seeing what it did to the innards of my coolant system- which was to basically leave coagulated crud all over the surfaces of the system- Yes, I can personally attest to the supporting stories around the “myth” that Dexcool is problematic. I’ve never had this problem with any other coolant in any of my other vehicles.

    Secondly, perhaps coolants are rated for 100k, but there’s no way I will ever leave coolant in my system for that long. Its cheap enough to change. Coolant does deteriorate and become more acidic with age.


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    WopOnTour

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    Dec 10th, 2010 (5:02 pm)

    edvard: WopOnTour,Given that I once used Dexcool in my Tacoma 10 years ago and seeing what it did to the innards of my coolant system- which was to basically leave coagulated crud all over the surfaces of the system- Yes, I can personally attest to the supporting stories around the “myth” that Dexcool is problematic. I’ve never had this problem with any other coolant in any of my other vehicles. Secondly, perhaps coolants are rated for 100k, but there’s no way I will ever leave coolant in my system for that long. Its cheap enough to change. Coolant does deteriorate and become more acidic with age.  (Quote)  (Reply)

    Edvard. Why would you use GM DexCool in a Toyota? GM has long attested that Dexcool is designed to function ONLY with a brand new internal cooling environment. Even on a GM vehicle that has had Dexcool since new, If the Dexcool has accidentally been replaced with traditional “green” coolant, you cannot return to Dexcool. So whomever switched you to it, did not follow recommended practice as per numerous GM TSBs.

    It’s all just chemistry exercise of course. All coolants will “react” with the metals, plastics, rubbers and various other materials they come into contact with. (and yes including oxygen and any other liquid ever added accidentally or intentionally to the system)
    GM validates these materials and chemistry to insure compatibility with Dexcool.
    Furthermore, suppliers of cooling system components for GM product must comply with various material standards and commit to chemical studies to confirm these components are complimentary to the use of Dexcool.

    This is the “price” of getting the benefits of a long life coolant, but it comes with numerous conditions and caveats, which are easy to control when selling a vehicle as “new” (and of course having it serviced by someone that is aware of the requirements and limitation)

    Rarely a GM vehicle is determined to be incompatible (for whatever reason) and regular coolant would need to be used (a case in point might be the Chevy Aveo) resulting in a more traditional coolant change interval.

    So despite some well documented and publicized incompatabilities that might have appeared back when Dexcool was first implemented (eg, rubber seals on intake gaskets on the old 3.4L 60 degree V6) Dexcool when properly implemented, continues to be the standard in long-life coolants to which others are compared and is factory fill in most every GM vehicle, including the Volt.

    WOT


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    Dan Petit

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    Dec 11th, 2010 (11:55 am)

    Excellent scholarship WOT.

    I’d like to see an additional datastream item for the ICE thermostat assembly if it has not already been incorporated: A thermostat position sensor.
    Also, I’d like to see some smart relays for the cooling fans that, at de-energize, automatically feed back to the ECM these several values: Fan motor slow down rate (bearing lubrication), resistance inconsistency pulses (circuit integrity), and harmonics present.
    thanks for the great article.


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    WopOnTour

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    Dec 11th, 2010 (1:09 pm)

    Dan Petit: Excellent scholarship WOT.I’d like to see an additional datastream item for the ICE thermostat assembly if it has not already been incorporated: A thermostat position sensor.Also, I’d like to see some smart relays for the cooling fans that, at de-energize, automatically feed back to the ECM these several values: Fan motor slow down rate (bearing lubrication), resistance inconsistency pulses (circuit integrity), and harmonics present.thanks for the great article.  (Quote)  (Reply)

    Thanks Dan.
    The thermostat on the Volt is capable of being electrically heated to facilitate electronic flow control, however it’s travel/position is based on a model that depicts current flow to its temperature. It is controlled by the ECM.
    Also, there are no relays used to control the engine cooling fans on the Volt, as they are electronically controlled for the most part. The ECM uses a pulse width modulation control signal wired directly to the control electronics which are integral to the motor itself.

    WopOnTour


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    Shaft

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    Dec 11th, 2010 (2:19 pm)

    DonC: The battery is kept between 0F and 80F for all SOC when the car is operating.

    My question is for the Volt off, not on.
    Also 0F seems pretty low for operating. I think it is 32F.


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    Steve Orr

     

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    Dec 11th, 2010 (2:35 pm)

    I am non-technical but what is the freezing point of DexCool ?

    I am concerned given that some days around where I live the wind blows terribly generating a significant windchill factor + I park my vehicles in a windy, cold parking lot… all day and sometimes do not go home from the office until 9pm. The vehicle will remain there from 6:30 am until 8:30 in the cold… I have measured -10.0 F on this parking lot – without windchill taking into effect. Will the Volt work after exposure to such an extreme outdoor cold exposure?

    Other days (same parking lot) the measured temperature I have seen in my vehicle has been 120 degrees! Likewise, can the Volt’s batteries and complicated systems handle extreme heat exposure day after day and still function ?

    Thank you


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    NJank

     

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    Dec 15th, 2010 (8:34 am)

    Matthew_B,

    The battery an electronics will have different operating temperature requirements. Silicon power electronics can generally run hotter than the battery, and can tolerate a higher inlet coolant temperature. You also rarely need to warm up the power electronics.


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    Chip Liland

     

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    Dec 15th, 2010 (10:22 am)

    Rashiid Amul,

    Todays ‘antifreezes’ are sophisticated coolents and are usually premixed, so the volt is no different from ant other modern auto.