How does IMA handle dead battery

[Rusttree]

I recently came back to my Insight after parking for three days to a dead battery (don't know if I left my headlights on or if the alarm went off). After getting the AAA guy to give me a jump, I noticed weird behavoir with the IMA. When I got in the car, naturally the SOC indicator was at zero. So I started driving and within a couple of minutes, it jumped all the way up to full (or close to it). Does anyone know exactly how the car manages power flow while parked? Did the power not actually flow out of the 144V'er, but rather the 12V'er?

Thanks.

[Yves M.]

I suppose that you forgot the dome light or something (or our 12v battery is dead). While parked, only the 12V can be active.

If the 12V is not present, the IMA also closes. Then the SOC is unknown. While driving, the IMA computes the SOC (actually it is the BCM) and then the SOC is displayed as you wrote (from nothing to something).

The 144v battery was not used while parked (unless you park in auto-stop and leave the car with the keys in)

[Rusttree]

Ah, excellent. It's good to know the circuitry is smart enough not to suck the 144V dry when the car is off.

[james]

Well, we have a different idea of what's smart The problem is, if the 12 volt battery is drained (and that's easily done since it's so small), you can't start the car, even with a push. All that energy locked in the 144 volt battery, and you're still stranded

[Rusttree]

Yeah, come to think of it, it would be nice to be able to override the BCM and let you tap some of the 144V when you run your battery dry.

Hm, maybe someone at Honda will get smart and make that feature in one of the new hybrids. It has the potential of putting AAA out of business.