Are you guys experiencing this 12 volt battery failure problem after coasting in reboot mode frequently or for long distances and/or periods of time.

I have had near death 12 volt battery experiences several times in my HCH. When I coast with the engine off, it seems the IMA's battery back pack is not connected to the 12 volt, so the 12 volt is on its own to power the car's electrical and electronic equipment (the 12 volt seems connected and to benefit from the charge in the IMA battery back pack during normal driving, regenerative driving, and even during auto-stop mode). This problem is only made worse when I coast with the engine off at night, and the 12 volt has head and tail lights to deal with also. But I haven't replaced my 12 volt yet (15 months and 31,000 miles old).

When you get to the point that the lights are dimming and the electronics start to fail, and the IMA shuts down, even when the car is running, it seems that the 12 volt's charge is so low that it cannot maintain a connection with the IMA battery back pack. It is then only a matter of time before the battery gets so low that the car will not run, or start.

I have found that the simple solution is the good old fashioned jump start with jumper cables to another car. The other car's battery will provide enought juice to start, and to reconnect the IMA to the battery, and then the car runs fine and everything works. Of course, if the battery is that low, then my reboot coasting is done for the night, and I drive normally to give the ICE and IMA a chance to put a real recharge back into the 12 volt battery. I have even started plugging my 12 volt into a battery charger at night at home, to try to get the battery a chance to be up to snuff of rhte next day's workout.

In the end, I think the real solution is to replace the factory battery with something more powerful, maybe bigger, but hopefully not too much heavier.