Greetings, Not sure if this has been considered elsewhere, but figured I'd share a random thought. I was thinking about the Model S's 12V system and I'm curious: Does anyone have any data on how much power is used by the 12V components of the car while driving? I know the instrument cluster, the 17" screen, fan blower, lights, sound, windows, etc all use the 12V system. Based on some of the vampire drain numbers people have seen (easily > 100 watts) I'd be willing to bet the 12V portion of the car uses a decent amount of power while driving, and I'd say something like 200W wouldn't be too crazy and probably a low estimate. So, driving for 3 hours would be 600Wh used by the 12V systems. That's two miles of rated range. It doesn't seem like it'd be difficult to throw together a ~1kWh lithium-ion pack that would be used to offset this 12V power drain while driving so some or all of that the power didn't come from the DC-DC converter. I would think that if you keep the voltage of the 12V system high enough so that the DC-DC thinks no power is needed, then it wouldn't push any power. So the DC-DC from my aux 1kWh battery would need to just be a hair higher than the output of the car's DC-DC I'd think. In any case, probably not worth it, but I could see it adding something like 1% range with somewhat minimal effort if it actually worked and the 12V system uses as much power as I figure it does while driving. It could also probably be done without the car getting angry, too, since I doubt it keeps tabs on the 12V loads in detail and just would welcome the reduction in load on the DC-DC. Unlike some power augmentation on the HV side, where the car would likely get pretty mad when things didn't add up as expected, I think we could get away with this one. If this is something Tesla implemented themselves by replacing the 12V with say, a 1kWh lithium battery, then they could charge this battery when the car charges, then utilize it for 12V loads while the car is in use (falling back to the DC-DC if needed) and just charge it up again using the existing DC-DC when the car is charging for a ~1% range boost at a minimal cost. *shrugs* Random thought. Edit: er, title fail. Should be "Potential avenue for"