Volusiano said:
One question I asked them about the battery pack is how does the thermal blanket for the battery in the 2012 weather package affect the hot battery in AZ weather. Doesn't it trap the heat in and not allow it to dissipate more quickly? They said the thermal blanket keeps the heat in the battery in colder weather, but keeps the heat out in hotter AZ weather. OK, I buy that if the internal battery temperature is lower than outdoors temperature. But once the battery heats up above outdoors summer temperature (>110F, for example), then I still think it's gonna take the battery longer to cool down. So I still think that the thermal blanket is still more hurtful than helpful for hot weather areas like AZ.
I was able to compute the battery internal resistance to be only 70 mOHms from my data logs. At that level, there really isn't a lot of heat being generated by the battery. I remember reading that the battery chemistry is endothermic during discharge so it is quite possible that the battery
doesn't heat up during driving. In fact, being an engineer for another large company that tends to over-engineer everything, I would be surprised if the battery internal resistance wasn't deliberatly tuned to to keep the temperature constant during heavy use (I know
we would). If so, the insulation makes a lot of sense for both AZ and VT.