My 2011 Volt has an "Energy Efficient Green Bose Radio" in it, and the first week I had the car I listened to it for 3 hours in my garage. The car suddenly went dead when the 12 volt battery was depleted. I had to get out my ancient heathkit battery charger and find a place in the engine compartment to charge it back up before the car sprung back to life. Maybe sprung is the wrong word. The engine started immediately even though my highvoltage battery was near full, and it took 50 minutes of driving to get the rest of the computer systems back to life.

My grandparents used to say the radio drained the battery, but that was with all those tubes and a vibrator supply making 300 volts out of 6. I never thought I'd see what they were talking about.

@Modern Marvel Fan

Initial Conditions: Both HV and LV batteries fully charged.

After 3 hours: HV fully charged, LV totally dead.

Indication: Plugging in charger dock did no good since the only working video screen states "car unable to charge".

I tried to talk to engineering about it but they would only talk to the dealer, not the know-nothing schmuck who put up $46,000.

GM's official response was: "DON'T LISTEN TO THE RADIO IN THE GARAGE" (!)

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So, I never did find out what the problem was until I just thought about it myself.

The Bose radio may be 'efficient', but turning on the accessories turns on 27 microcomputer systems (apparently all old fashioned nmos and not cmos, or else they turn on plenty of other crap needlessly that drains the battery)..

The thing i've learned to do is not turn the car on in mtc mode for more than a few minutes.

Would be nice if someone at GM knew something about electricity. hehehe. Then they could give a half-brain-dead answer to the next person who experienced the same thing.