Weber says 12v battery can't start the ICE

[WopOnTour]

Originally Posted by Texas

How Ironic. It's you, you silly dude, who are not thinking ahead. You are talking about the tiny power loads used by cars today when they are not running. Simple loads because only 12V batteries (or other small electrical energy storage system) are available.

If you were to read my past posts on SOTS you would understand that I'm talking about much greater functionality. That functionality requires more power. Things like advanced security (how about video surveillance and downloads to the Internet, video monitoring, calls to 911 after you approve it via your phone, etc.) What about advanced battery management in the hot sun? If you had a way to get power into the vehicle (solar system) then you could actually run cooling or heating systems if say the temperatures get dangerously low or high. What about preparing the vehicle as you approach? You could heat the battery on a -20 degree day, for example. Perhaps ventilate the cab and then run the A/C a bit so your wife doesn't burn her butt on the hot seats.

So, perhaps you should worry your tiny head a bit more before you further expose your lack of vision or understanding. Don't worry, just leave the real work to more competent people. You will see what car 2.0 can do soon enough.

OK, So perhaps I misunderstood what you were saying and didnt read any previous thread you are referring to- I only responded to what you said here, which in the context of the thread title... well, never-mind

So are you talking about the Volt? or some other pipe-dream vehicle that you invision? (can you provide a good external link that documents SOTS?)

FYI for safety's sake, the Volt's HV battery is completly isolated from the rest of the vehicle by the battery managment system, through a pair of HV isolation contactors (one on the HV+ rail, the other HV-) once the vehicle has achieved it's "at-rest" power mode. (these contactors are closed by the system once station charging is detected)But if you're attempting to create some sort of aftermarket charging accessory, you obviously plan to obtain a connection SOMEWHERE to the HV source in order to use your so-callled SOTS features. I guess you could always just tap into the battery inside the box prior to the isolation contactors OR perhaps tap into the CAN bus command structure to create your desired event triggered power modes. The problem is GM has never been known to be very "open-source" when it comes to their proprietary CAN bus commands., standards be dammed. Also keep in mind the vast majority of the Volt's body electrical, lighting, and accessory systems will still operate off the 12V source, so you'll have to charge that too if you plan to suck off it for any function. If that's dead you're going nowhere even if the HV source is at full 80% SOC (no "junp assist" feature is being implemented AFAIK)
WOT

[Andy0x1]

Originally Posted by Texas

If you had a way to get power into the vehicle (solar system) then you could actually run cooling or heating systems if say the temperatures get dangerously low or high. What about preparing the vehicle as you approach? You could heat the battery on a -20 degree day, for example. Perhaps ventilate the cab and then run the A/C a bit so your wife doesn't burn her butt on the hot seats.

I live in a cold climate, and trust me... The amount of solar energy you could extract assuming your vehicle somehow (magically?) wasn't covered in frost / ice / snow / road salt / dirt / etc... (esp at off angles to the sun) wouldn't even be enough to provide even a 1 degree rise in cabin temperature not to mention the sun isn't shining on it at night.

On a side (supportive) note; I just installed a brand new OPTIMA Yellowtop Deep cycle battery into my summer car (which I haven't been driving) and that thing is always completely dead within says of providing it with a full charge.

This is even without arming the Alarm (apparently even disarmed it puts a heavy drain on the electrical system?)

I plan to put a multimeter on the car tonight to get an idea as to how many watts the battery is pumping out to maintain my radio's clock! I can't imagine the audio amplifiers in the trunk consume much of anything without the rem wire being attached. Maybe I'll be surprised! It just amazes me as to how quickly that battery goes dead parked.

[Matthew_B]

Originally Posted by Cab Driver

The 12 volt battery is already there and it wouldn't be necessary to add a 12 volt starter motor. What would be needed would be some power electronics to feed the inverter for the generator from the 12 volt battery. I'm guessing they didn't want to take the time to design it in and / or they didn't want to pay the cost to get the limp home ability.

That converter exists in the Prius. It allows "jumping" the car using another car's 12V.

It also happens to be one of the most common ways to kill a Prius power electronics block if someone reverses the jumper cables. The HV to 12V inverter/converter isn't polarity protected. The power electronics box isn't component repairable and then you're buying a whole new power electronics box.

[Cab Driver]

Originally Posted by Matthew_B

That converter exists in the Prius. It allows "jumping" the car using another car's 12V.

It also happens to be one of the most common ways to kill a Prius power electronics block if someone reverses the jumper cables. The HV to 12V inverter/converter isn't polarity protected. The power electronics box isn't component repairable and then you're buying a whole new power electronics box.

That's interesting. Perhaps this is a bigger reason to not design in starting from 12 volts than the time or cost issues I suggested.

[Altazi]

Originally Posted by Cab Driver

That's interesting. Perhaps this is a bigger reason to not design in starting from 12 volts than the time or cost issues I suggested.

It is difficult and expensive to protect a high-current circuit against reverse polarity faults.

[WopOnTour]

Originally Posted by Matthew_B

That converter exists in the Prius. It allows "jumping" the car using another car's 12V.

It also happens to be one of the most common ways to kill a Prius power electronics block if someone reverses the jumper cables. The HV to 12V inverter/converter isn't polarity protected. The power electronics box isn't component repairable and then you're buying a whole new power electronics box.

AFAIK only the fist gen (NHW10) Prius has the "jump assist" feature.However the current Ford Escape and the GM 2-mode hybrids still have this capability. (not 100% sure if the Volt will however it is likely) This permits a conventional 12V charger or running boost vehicle to charge the HV battery in a controlled fashion for a time-limited period.

When engaged by a technician, the inveter/converter takes the 12V (charging likely at 13-15V) and using a bank of step-up transfomers and capacitors is able to create a charging current into the HV source. On the GMs (of which I am quite familiar- I drive one) you will need to use a Tech2 scan tool to initiate "jump assist" so it's considered a field service procedure only, and used only if some sort of system issue, results in a badly discharged HV battery (i.e. <25% SOC)

Keep in mind as is the case with all "strong" hybrids (Prius, Escape, 2-mode GMs) the 12V is not required for actually providing any "cranking" power, as the ICE is spun by one of the motor/generator units. It's just that 12V rail is neccessary for ALL of the system managment electronics and in vehicle networking. So lose your 12V source and you're SOL and walking, but it of course CAN still be charged or boosted in a conventional fashion much like any other vehicle.

*and much like any other vehicle accidentally reversing the polarity while boosting/charging can damage numerous sensitive electronic packages within the vehicle.

HTH
WopOnTour

[jscott1000]

If my Volt didn't "start" for some reason I think I would call AAA before I messed around with jump starting it.

It is entirely likely that if you parked your Volt at the airport for several weeks that your 12V battery could be dead. It's happened to me before and a jump start later I was on my way. But with a Volt you are risking some very high priced electronics if some garage monkey reverses the polarity.

[Altazi]

Originally Posted by jscott1000

If my Volt didn't "start" for some reason I think I would call AAA before I messed around with jump starting it.

It is entirely likely that if you parked your Volt at the airport for several weeks that your 12V battery could be dead. It's happened to me before and a jump start later I was on my way. But with a Volt you are risking some very high priced electronics if some garage monkey reverses the polarity.

This is where the solar panel option for the roof could make sense, keeping the main battery topped-off, or slowly trickling its way to a full charge. That is, of course, unless you park inside the parking garage. Hopefully there would be charging receptacles available in the garage.

[hermperez]

The 12v battery wont have any huge loads on it, just housekeeping functions.. it probably will be good for the life of the car.

There is an issue with long term storage of any electric car and it will have to be kept in mind. High temperatures greatly increase the self discharge rate. Lets say you arrive at the Phoenix airport with your Volt at the 30% point.. you better make some long term charging arrangements while parked or you will face a $12k repair bill in a couple of months... better off taking a taxi.

[nater]

My EV has a 12v Aux battery. It is used to engage the contactor. Without a 12v battery, you can't "start" any car, including the Volt. Forget turning over the ICE, the car won't move, even with the big battery full.

Nate