What is the exact group size/battery size of the 12v Lead Acid battery?

Interesting idea. I don't know the answer at all here, but with the brain trust behind JB and crew, you'd think they would have thought of this already.

I suspect there's some underlying performance adv. with the battery in place now. (Old school jump starting, etc.)?

This is interesting and I would also be interested to know why they chose to go with the traditional PbA 12 V battery. Perhaps they didn't want to introduce more "first time ever" features than necessary on a car that already has so much new and partly untested technology? A regular 12V battery can be replaced anywhere in the world and is at least a very proven and well developed technology. Also, some of the peripherals/electronics/lights/fluid pumps/locks etc. etc. that draw from the 12V battery are not designed in-house by Tesla and have been developed for use with lead-acid 12V batteries. However, I wouldn't think that for example the rear tailgate motor or the windows washerfluid pump would be able to tell if the power came from a 12V LiIon battery instead? Maybe it's just that if Tesla had trouble with any of these parts the supplier would complain that the problem was because the battery was not a "regular one"?

The Model S has been observed to charge its PbA battery at well over 15 V, perhaps to "condition" the battery. See the 12 V issues thread. I don't think that other cars do this. I would try out the Li starter battery on a conventional car until more is known about compatibility with the Model S unique charging algorithms.

GSP

did you ever figure out the battery size?

How will a lithium ion battery cope with being charged by a lead-acid charger? I suspect the MS will keep the battery float charged at about 13.8V continuously, it won't behave like a CC/CV charger like a li-ion cell expects.

Plus, presumably, the accessory battery is kept at a 100% SOC as much as possible by the car and this is very bad for Lithium-Ion batteries.

gavine said:

Plus, presumably, the accessory battery is kept at a 100% SOC as much as possible by the car and this is very bad for Lithium-Ion batteries.

Click to expand...

That's easy to fix... Use four cells at well under 4v each to make 12.7v static / 14 volts charging.