How big of an A123 cell would it take to start a car?

[bruce750i]

I remember having one of those wire chargers, it would heat up and cut through anything plastic it was laying on.
I had a 12v lead acid battery blow up in one of our work vans this year. It went Boom after a one hour trip of 15 to 16 volts charging it the whole time. Funny tho the battery still started the van one more time to go get another one. We changed the alternator only to have the same problem. After doing some reading the voltage was being controlled by some CPU. I guess thats where they get the voltage cut-off.