I am one of the Volt CAB drivers and thought I could answer a question that has come up a few times on this website. The Volt does not tell you how many kWh are used in the EV mode, but I have a dedicated TOU meter for the Volt charger so I can measure the amount of kWh’s used to charge the vehicle. As an example, during my trip to the electric car meet up in Montclair, NJ yesterday, I drove 110.2 miles total and 44.5 were in EV mode and 65.7 using the gas generator. I burned 1.6 gallons of gas during the trip. But, to answer the kWh question, when I charged the car at home in the evening, the car took 12 kWh of electricty to charge the depleted battery.

It looks like it would have cost me $0.72 to fill your tank that night.

In the last twelve months I spent an average of $68 per month of fuel for the Prius. Seems like it will be hard to spend that much on electricity for the Volt.

Now I have to figure out whether it would make more sense to route my solar generation through the EV meter rather than the house meter (both TOU).

I drove 110.2 miles total and 44.5 were in EV mode and 65.7 using the gas generator. I burned 1.6 gallons of gas during the trip. the car took 12 kWh of electricty to charge the depleted battery.

Assuming the national average of $0.12 per kWh electricity and $3.00/gallon of premium gas, you went 13.7 miles per dollar of gas and 30.9 miles per dollar of electricity.

(I pay $0.0986 per kWh, so I would have gone 37.7 miles per dollar of electricity)

Your charging efficiency of ~86% perhaps is a bit lower than expected but not excessively so.
Your TOU device, is it a smart meter or some sort of accessory at the breaker?
What is its resolution? (ie was it 12, 12.0, 12.00 kwh? )
WopOnTour

Your charging efficiency of ~86% perhaps is a bit lower than expected but not excessively so.


Very typical of chargers and power supplies.

Robert Becker: Can you please report what the temperature was on the night that it took 12 kWh to charge the battery? Just wondering if there was much battery conditioning going on. Also, did you pre-condition the cabin temp on grid power before you unplugged? These things could explain some of the power draw, which would indicate a higher than ~86% charging efficiency.

....which would indicate a higher than ~68% charging efficiency.

~86% was stated

Oops, good catch. I edited my post to say 86%.

Robert Becker: Can you please report what the temperature was on the night that it took 12 kWh to charge the battery? Just wondering if there was much battery conditioning going on. Also, did you pre-condition the cabin temp on grid power before you unplugged? These things could explain some of the power draw, which would indicate a higher than ~68% charging efficiency.

The car was parked in my garage all night while it was charged. The garage is probably around 50 degrees although I did not measure the temperature. I did not precondition the cabin temperature on grid power before unplugging.

Robert,
It would be interesting to know how efficient the 110V charger is. Maybe you could use it one night as a comparison.

Robert,
It would be interesting to know how efficient the 110V charger is. Maybe you could use it one night as a comparison.

Only my 240v Volt charger is hooked up to the dedicated TOU meter. My 110v outlet in my garage is hooked up to my regular house meter, so I couldn't give you an accurate kWh read if I charged with the 110v outlet.

I am one of the Volt CAB drivers and thought I could answer a question that has come up a few times on this website. The Volt does not tell you how many kWh are used in the EV mode, but I have a dedicated TOU meter for the Volt charger so I can measure the amount of kWh’s used to charge the vehicle. As an example, during my trip to the electric car meet up in Montclair, NJ yesterday, I drove 110.2 miles total and 44.5 were in EV mode and 65.7 using the gas generator. I burned 1.6 gallons of gas during the trip. But, to answer the kWh question, when I charged the car at home in the evening, the car took 12 kWh of electricty to charge the depleted battery.

You've helped answer another good question here too... You got 41MPG over your 65.7 miles on the generator. Not too shabby.

This is great info. Can you post the information for a few days? Perhaps even with preconditioning? Thanks

Your charging efficiency of ~86% perhaps is a bit lower than expected but not excessively so.
Your TOU device, is it a smart meter or some sort of accessory at the breaker?
What is its resolution? (ie was it 12, 12.0, 12.00 kwh? )
WopOnTour

I think you all got the charging efficiency wrong, or perhaps some new information that I didn't know about.
It has been published that the Volt will maintain State Of Charges so that it depletes its battery by 50%, ie, between 30% and 80% SOC. And it has been known that the battery is 16 kWH and so we replenish 8 kWH.

Now if you used 12 kWH of energy to store a usable energy of 8 kWH, then the charging efficieny is way horrible than what all of you have implied!

Simple math: Efficiency = 8 kWH/ 12 kWH = 66.67%!!!

This is one bad battery and battery charging technology!

Anyone else noticed this?

Are we actually refilling 10.32 kWH (~86% efficiency) or 8 kWH of battery energy?

I think you all got the charging efficiency wrong, or perhaps some new information that I didn't know about.
It has been published that the Volt will maintain State Of Charges so that it depletes its battery by 50%, ie, between 30% and 80% SOC. And it has been known that the battery is 16 kWH and so we replenish 8 kWH.

Now if you used 12 kWH of energy to store a usable energy of 8 kWH, then the charging efficieny is way horrible than what all of you have implied!

Simple math: Efficiency = 8 kWH/ 12 kWH = 66.67%!!!

This is one bad battery and battery charging technology!

Anyone else noticed this?

Are we actually refilling 10.32 kWH (~86% efficiency) or 8 kWH of battery energy?It was revealed a few weeks ago that the Volt utilizes 65% (~10.4 kWh) of it's 16kWh capacity.
HTH
WOT

Thanks WOT. I somehow missed this very important info. So what SOC are they using as default for the 10.4 kWH depletion?

I thought that 10.4kWH was before the ICE kicked in. I expect that you can run the battery way, way down if you work at it. I wish the charging message from OnStar told me how many kWH the charge took when it completed. Then I could compare to the meter to find out what percentage is charger inefficiency, conditioning the battery and conditioning the cabin.

I thought that 10.4kWH was before the ICE kicked in. I expect that you can run the battery way, way down if you work at it. I wish the charging message from OnStar told me how many kWH the charge took when it completed. Then I could compare to the meter to find out what percentage is charger inefficiency, conditioning the battery and conditioning the cabin.

To the best of my knowledge, you can't run the battery down further than the ~30% state of charge after that 10.4kWh has been depleted. The generator will turn on, and the car will limit power output; you'll even get a reduced power message on your screen if you're demanding more power than the generator can provide.

Then again, I'm just book smart, unlike some others who already have a Volt (points at Colin) ;)

A Kill-A-Watt meter will measure exactly how many kwh you are putting into the volt when plugged into a 110v.... In the aforementioned scenario, you have to remember that after it's charged the vampire power still draws an unknown amount. The engineer told me that this vampire power is the same as 3 glade plug-ins.....this means nothing because we don't know which type of glade plug ins are being referred to.....

A Kill-A-Watt meter will measure exactly how many kwh you are putting into the volt when plugged into a 110v.... In the aforementioned scenario, you have to remember that after it's charged the vampire power still draws an unknown amount. The engineer told me that this vampire power is the same as 3 glade plug-ins.....this means nothing because we don't know which type of glade plug ins are being referred to.....

I'll unplug a few night lights and call it even:-)

...unless it's NOT parked in a climate controlled garage and it's very cold. Hopefully, I'll find out firsthand how much power overnight battery conditioning is used...this winter! (early this winter?)

#105 from todays blog.
Lyle Says
Nov 19th, 2010 (12:10 pm)Jackson: Lyle, is your 220V charger on a separate meter?

No.
For those who ask about electric energy use, I am told OnStar will issue a monthly report showing exactly all the energy the car consumed from the grid in kwh. I will post it here immediately for all to see.
I charge every night at home at 240-v (usually about 7.5kwh I’d estimate) and as much as I can during the day at 120-v ( from 4 – 8 kwh).
The Volt’s dash does NOT show kwh consumption.

This is great info. Can you post the information for a few days? Perhaps even with preconditioning? Thanks

Here is some more data on how many kWh the battery takes:

column 1: date
column 2: miles left unused
column 3: kWh drawn
column 4: miles noted after charge

Nov-9 8 10 38
Nov-10 8 9 37
Nov-11 14 7 35
Nov-12 16 7 35
Nov-13 0 12 38
Nov-13 22 6 37
Nov-14 27 3 37
Nov-17 23 5 37
Nov-19 23 6 38
Nov-20 0 12 42

Sorry, I don't know how to post an excel chart on this website without the spacing being altered.


The "miles noted after charge" is not the same as how many miles I actually go on a full charge. The furthest I have been able to on battery mode with one full charge was 53.8 miles (it was 53 degrees outside).

It should be noted that HTML (and this forum) sucks for space aligned tables by default. Let's try this:



date miles left unused kWh drawn miles noted after charge
11/9 8 10 38
11/10 8 9 37
11/11 14 7 35
11/12 16 7 35
11/13 0 12 38
11/13 22 6 37
11/14 27 3 37
11/17 23 5 37
11/19 23 6 38
11/20 0 12 42

I tried using the HTML tag and either PRE or TABLE. But that didn't work so well. Even doing this with the CODE tag was rather a PITA.

I have now had the opportunity to fully charge the battery multiple times. I have found that the Volt continues to require 12 kWh to fully charge the battery. My TOU meter does not get any more exact then whole numbers unfortunately. My car is parked in my garage so it doesn't require preconditioning. Only once it took 13 kWh.

I think it was Motor Trend that said that they filled the Volt completely from a fully depleted state and it took 12.9 kwh. Since your charger only reads whole numbers, do you think it might read 12 kwh up until the meter clicks over for a full 13 with no rounding up or down? That may be why the 13 popped up once when conditions were just a bit less that optimal for recharging.

It looks like it would have cost me $0.72 to fill your tank that night.

In the last twelve months I spent an average of $68 per month of fuel for the Prius. Seems like it will be hard to spend that much on electricity for the Volt.

Now I have to figure out whether it would make more sense to route my solar generation through the EV meter rather than the house meter (both TOU).

How did you get the 72cents to charge 12kwh?
I am in CA on SCE and the lowest rate they have for dedicated meter tou is 11 cents. Your numbers would be 6 cents.

Thank you for posting the charging information. I have one more question. Did it take more tha 8 hours to charge it when fully depleted? I'm trying to decide whether I will spend the money on a 220 charger. It would also be interesting to see what the efficiency difference is between the 220 and 110 chargers.

My rate on my TOU-EV meter from midnight to 6am is 0.068 per kilowatt. The Volt is smart and only charges in that window, unless I get crazy and charge after my school pickup. That's usually only an hour or so of charging, but I think my rate is bumped to 0.18 at that point.

I am pretty sure it has yet to take more than 4.5hrs to charge.

My rate on my TOU-EV meter from midnight to 6am is 0.068 per kilowatt. The Volt is smart and only charges in that window, unless I get crazy and charge after my school pickup. That's usually only an hour or so of charging, but I think my rate is bumped to 0.18 at that point.

I am pretty sure it has yet to take more than 4.5hrs to charge.

What Electric company are you with? I met with SCE and their best deal for an EV is a second dedicated meter for the EV (called TOU EV-1). The rate is 11c winter and 12c summer when you charge between 9pm and noon. I would love to have your rate available. They also have a rate for TOU but you use the same meter that all the other home use is on. When I read the tariff there is 2 portions of the billing --delivery and Generation and the total of the 2 comes to either 11c or 12 c depending on time of year. The generation is a blended rate as they have 2 sources and it depends on the percent they get from each. Any more info you can give would be appreciated.

If you are with SCE is it possible you have a old rate that is Grandfathered in and not avalible currently?

What Electric company are you with? I met with SCE and their best deal for an EV is a second dedicated meter for the EV. The rate is 11c winter and 12c summer when you charge between 9pm and noon. I would love to have your rate avalible.

Sounds like LA Dept of Water & Power. Their rates are way cheaper than SCE or PG&E.

Sounds like LA Dept of Water & Power. Their rates are way cheaper than SCE or PG&E.

Yes LADWP has great rates. And, on top of the already reduced base Time-Of-Use rate, there is a discount for EV use. My effective base rate, between 8PM and 10AM weekdays and all weekend is 0.02155 from June to Sept and .028900 from Oct to May. With my 5 day work week, that is going to average about $6 for the whole month of commuting.

Peak charging from the wall is about 12.6 KW and on average normal use I see 11.6 KW average daily.

I just received my first full month electric bill with the Volt, I paid $26 for 29 days. Almost every day I charged from a depleted battery. I think that is very impressive.

Robert,
It would be interesting to know how efficient the 110V charger is. Maybe you could use it one night as a comparison.
I recently checked how much electric energy it takes to recharge my brand new 2012 VOLT at 110V. The result 12.0kwhr.

This is how I made measurement.
I drove 40.1 miles, and cars indicator showed I had 1 mile left. I started charging at 11pm and immediately turned off all lights and other loads and recorded kwhr meter reading. Just before 8:30 am the dashboard indicator started flashing indicating charging completed. The car indicator showed 41 miles available. The electric meter reading indicated that a total of 13.7kwhr had been used.
The following night with no vehicle charging I repeated the electric meter measurements to find out what energy my base load used - refrigerator (door not opened during period), computer and TV in standby mode, electric water heater maintaining temperature (no hot water used). The total energy used over the same time period was 1.7kwhr. Therefore I conclude that charging the VOLT used 13.7-1.7=12.0kwhr. The outside temperature reached a low of 68F both nights, home heating and cooling were turned off.
Admitted that this was not a very scientific measurement, but I think it gives a reasonably close indication

If you look at my signature you can see the usage on out volt from our TED system.

select History and MTU #4. It is a direct measurement of the line to the Volt Charger. There is a monthly, daily and hourly summary with costs as well. The costs are a bit deceiving as the MTU #2 is the solar feed in! ;)

I recently checked how much electric energy it takes to recharge my brand new 2012 VOLT at 110V. The result 12.0kwhr.

This is how I made measurement.[...]

Get a $20 Kill-a-watt meter, it's easier & more precise. I think the amount to charge will vary a bit depending on the temperature, how much the various cooling systems have to run. The most I've measured so far is 13.53 kw-hr from totally empty.

The number is in myvolt.com now. How about using that? Would be interesting to compare it to your guys methods.


See: Calculating-your-EVSEs-efficiency-using-MyVolt.COM-data
http://gm-volt.com/forum/showthread.php?9136-Calculating-your-EVSEs-efficiency-using-MyVolt.COM-data

P.S. I have a TED5000 but it is on my whole house. I do have a Kill-A-Watt but I use the 220v SPX charger. I could try the 110v one tho.

Yes LADWP has great rates. And, on top of the already reduced base Time-Of-Use rate, there is a discount for EV use. My effective base rate, between 8PM and 10AM weekdays and all weekend is 0.02155 from June to Sept and .028900 from Oct to May. With my 5 day work week, that is going to average about $6 for the whole month of commuting.

Please help me to compare MY cost of electricity to what others are posting on this forum. My Volt charged 217.34 Kwh for the 30 day period between 8/18 and 9/18. Con Edison, my local electricity extorter charges as follows: supply charges of $0.088 per kwh, plus delivery charges of $0.1098 per kwh, plus $0.0498 kwh (system benefits charge) plus $0.0467kwh new york temporary surcharge, plus 3% sales tax on all of this. So...best as i can figure my 217.34kwh cost me just about $66 or $0.3036/kwh.

Obviously, there are lots of municipalities and utilities who seem to be charging alot less, offering time of day billing, separate meters, fixed rate plans for EV's and more. Do the rates that you folks are taking about include the cost or the electricity, the delivery and all the other charges I listed. You are talking about an' effective base rate of 2.1cents and 2.89cents. If this is your base rate before all the add in costs, please tell me what your bottom line kwh cost is. If this is your bottom line cost, then the screwing that we here in NY are getting is completely insane.
a penny for your thoughts
STuart B2209

Please help me to compare MY cost of electricity to what others are posting on this forum. STuart ... B2209
New topic so please start another thread. Good for many reason but you'll get more lookers/responders too.

is there a way to edit my post and turn it into a new thread? or do i need to start over and post it as a new thread?
Stuart B2209

is there a way to edit my post and turn it into a new thread? or do i need to start over and post it as a new thread? Stuart B2209
Start over as far as I know but this is trivial. As the author of a post you can can just edit the existing one using "Edit Post" at the bottom of your post. In a Windows environment just put your cursor in the text and press CNTL+A to highlight all then CNTL+C to copy it to your windows clipboard. Then go create the thread and do CNTL+V to paste it. Or use right-click and use the context sensitive menus that pop up when you are hovering over the text. I'll delete these post when you are done.

Stuart, I agree with Scott. A new thread would be great. FYI, in CA the transmission and distribution charges are separated out from the power cost. And generally CA is on a tier rate structure, where the baseline costs less and the more you use the more you pay. However, your charges are high by CA standards and CA electrical rates are higher than the national average. The most EVs would pay in CA would be $.14 if you charges at night. That would be a total per kWh price.

Charging my Volt with 110 V averages about 12.5 kWh. However, when the battery is depleted, the energy information screen indicates that an average of 10.5 kWh has been used. Thus, I assume my charging efficiency is (10.5/12.5) x 100% = 84%. Is this correct? What accounts for the losses? Thanks.

Charging my Volt with 110 V averages about 12.5 kWh. However, when the battery is depleted, the energy information screen indicates that an average of 10.5 kWh has been used. Thus, I assume my charging efficiency is (10.5/12.5) x 100% = 84%. Is this correct? What accounts for the losses? Thanks.

Batteries are never 100% efficient it takes more input energy to charge the battery than the battery can hold or return.

Lithium batteries themselves are typically extremely efficient at around 99% efficiency DC In to DC Out. The main losses are in the power electronics conversion from AC to DC power + wire losses.

Please don't forget cooling. I have a Volt on order, and I'm not as familiar with it as with the Leaf, but it has been established on the MNL forum that 240V charging is about 85% and 120V charging is about 70% efficient. The main suspect for the low efficiency are the parasitic losses from the cooling pump. The charger itself is probably 90 or 92% efficient, but if you add all the losses together, a disappointing amount of energy is lost. From the opinions and observations voiced in this thread, it looks like the Volt is getting similar numbers.

Lithium batteries themselves are typically extremely efficient at around 99% efficiency DC In to DC Out. The main losses are in the power electronics conversion from AC to DC power + wire losses.More like 90% for the recharge. Other losses would be additional.


Please don't forget cooling. I have a Volt on order, and I'm not as familiar with it as with the Leaf, but it has been established on the MNL forum that 240V charging is about 85% and 120V charging is about 70% efficient.The Volt is more like 87% and 86%. 70% seems shockingly low. I doubt it -- the losses would be constant and they're very small so the numbers wouldn't seem to add up -- but I guess anything is possible.

And congrats on your Volt. You'll love it. There are a few people here who have both. They make a nice combination.

Charging my Volt with 110 V averages about 12.5 kWh. However, when the battery is depleted, the energy information screen indicates that an average of 10.5 kWh has been used. Thus, I assume my charging efficiency is (10.5/12.5) x 100% = 84%. Is this correct? What accounts for the losses? Thanks.

Most energy losses ultimately end up in some form of absorbed/unused/waste heat.

Charging my Volt with 110 V averages about 12.5 kWh. However, when the battery is depleted, the energy information screen indicates that an average of 10.5 kWh has been used. Thus, I assume my charging efficiency is (10.5/12.5) x 100% = 84%. Is this correct? What accounts for the losses? Thanks.

Most energy losses ultimately end up in some form of absorbed/unused/waste heat.

The battery *and* its charger are also kept at an optimal tempature to accept the charge.

Most energy losses ultimately end up in some form of absorbed/unused/waste heat.

Actually, all of them do. Tis impossible to be sure of any thing but Death and Taxes -- and Entropy.

I have to disagree and say that it is a scientific measurement, given that you've even taken the ambient temperature, refrigerator conditions etc. into account. Sure, it won't be as precise as a dedicated meter (like the Kill-a-Watt meter), but this is quite an effort. Thanks for the report!

-Venky
2011, Viridian Joule #3490, Rear Camera, Premium Trim, Leased 7/5/11, Odo: 1550miles (> 1400 on Electric)
1999 Chrysler 300M

Hi. I have a Volt and I charge it on 110v and measure the draw from the grid with a Kill-a-Watt meter. Generally takes 12.25 kWh to restore the 10 kWh the Volt says it used, so 81.6% efficiency.

I'm thinking fo getting a 220v Blink charger. From this thread, sounds like the efficiency is the same regardless of whether I'm charging from 110v or 220v, but just hoping someone can confirm that. Thanks

please forgive me posting to an old thread, but I would like to know why the available hours after charging seems to vary. Mine seems to always be 36 hours, while many of you report 40 hours or more. Is this a re-set based on my driving style (yeah still a leadfoot) or is it due to the amount of hours used prior to charging ?

Full charge (totally depleted usage wise) battery for me on 110v charging has never gone over 10hrs. So in usage terms, full 10hrs (~10K usable for driving) charge takes me ~40miles (less in the winter where I live) or what most peeps here report as about 4mi/kw depending on climate.

Take that 4mi x my cost per kwh (in my case it's nite rated @ 4.5 cents kw/h but after all the bs taxes, line charges, drop fees etc I figure closer to 11.5 cents per kw/h) or $1.15 per charge. So I can drive ~40 miles on (is a tad more b/c a minor part of the energy in the overall charge that doesn't go directly to the pavement). So for me about $1.15 of non-exaggerated e-fuel costs will complete a full tank of electrons.

A fully depleted charge here runs right at 4 hours with a SPX 240 Level 2 charger. Mostly we charge on demand immediate. The TED shows the charger actually draws 3.4 kw. So 3.4 kw X 4 hours = 13.6 kWh. I suspect is is slight less, more like 13.3 kWh as the last 15 to 20 minutes the draw drops down gradually. There are some losses in charging to get 10.4 kWh in the battery.

Fortunately the solar does it for mostly no charge from the power company. We are definitely net zero 8-10 months out of the year, and soon with a 3.9 kw solar add coming we will be net positive. The way the power company accounts it it will be next Jan. to see the effect

Actually scrubbag, kilowatt is expressed as kW. But otherwise, you are correct.