Very Strange:
Started car in 4deg temperature (sitting a couple days) and it started. I flipped on the Defroster and waited five minutes for it to warm up.
Came back to drive it and it was running-BUT no power to the radio, dash lamp flickering, EPS lamp lit, and couldn't rev engine.
I turned it off. Jumped with Marine battery and started fine. I waited a few minutes-disconnected cables and still running fine. Everything has been fine since. (2 days now)
I measured the battery on the next COLD start (now 17degs out) and there was no drop below 12vt-in fact it instantly jumped to 13+ charging voltage.

Is it possible the alternator was frozen? Computer/temperature issue? Battery connections bad?

For now I'm keeping that marine battery in the car. Thanks

ps. Battery has been replaced but now is 6 yrs old

Look in there and tell us if you find an alternator.
Was it doing all this at the time you stepped away from the car?

The cars can do some awfully weird stuff when the 12v battery is weak or dead and the car is jumped while the key was left on.

If you have a good battery in there now, just see how it rolls now. If the problem doesn't come back then you might assume the battery was the problem.

Thanks for the quick response. Not sure what you meant by looking for an alternator?? I haven't been under a hood since my 1970 Chevelle SS 454. Giving away my age here.

Best answer I can give (since the Hybrid starts almost with a hush) is that once it turned over I probably jetted out of the vehicle. I may have flipped the defrost (adding a load) on before my exit. I wasn't in the vehicle long enough to notice anything. Don't mind the 4degrees but hate the wind.

Upon my return the idle seemed unusual and the dash barely visible while flickering. No readout on the radio/clock either. I think I'd best grab a new battery and like you say if the problem doesn't return it probably was the issue. Just weird to see the vehicle running. I'd be keenly interested what will happen if the temperature drops to '0'. Given that opportunity
I suppose I could also move a cable or two with the lights on (which they weren't at the time) as a dead give-away it's a connection. If that occurs, or anything worse-I'll get back with a report Thanks again.

There is no alternator.

Charging of the 12v battery is handled by the IMA motor and the myriad of electronics behind the rear seat.

The 12v battery is mostly present to get all the control units operating when you turn the key on. If it's weak, the electronics can 'go nuts'...... and voltage spikes from a "hot jump start" can cause all sorts of weird issues and a ton of fault codes.


Another possibility might be a flaky ignition switch, but I'd expect that to show up again in the future as another very similar event.
If it happens, take notes of what all items and systems are affected and see if they all might share a common circuit.


Just guessing here.
Ok

Cold temps shouldn't present anything out of the ordinary for the car other than the usual extra demand on the batteries, but be aware that with very cold temperatures and/or low state of charge of the IMA battery you might get to hear the conventional 12v starter operate instead of the usual instant engine operation (hushed, or whatever you called it).

HTH

Won't bother you with quotes but you've given me some valuable insight. I had no idea the IMA did anything but assist with horsepower. Almost makes me wonder if a weak 12vt battery could create a false IMA failure (code) in reverse. My indicator comes and goes. I loved this car from day one for all the feedback (and stats on the dash) while driving. Be tough to get rid of it. So far 81,000 in my ten years on the original IMA battery. Appreciate all. Tnx

That's what it's there for, it is a battery pack and motor-generator to assist the "smaller than usual" gas engine.
(Much higher tech that that of course.)




You'd need to know what IMA fault codes it is setting, and then decide if your theory was correct.

The IMA battery is NiCd, and it will wear out like any other rechargeable NiCd battery.

At 10 years, it could be nearing the end of its life expectancy so don't be surprised if it does.


HTH