were you having issues? what did the old one read? what does the new one read? what brand did you buy?
I replaced the OEM with another Toyota OEM battery. About two weeks ago I got a really strange code that didn't make sense, P0A7F. I have not seen any problems with my pack. The code has not come back so I'm pretty positive that it was the twelve volt that was pulling power off of the main pack causing the P0A7F code. I got 50-51 months out of the original 12V before it ended up dying. Let my add I'd pull the car into the garage at night with 7 or 8 bars and in the morning I would go to start the car and I would notice the main pack was down to 2 or or 3 bars. Since installing the new 12V, I park it after coming home from work with 8 bars and 12 hours later I still have 8 bars in the morning.
You're thinking the hybrid battery would attempt to charge the 12 volt overnight? I'm not sure, would it do that? Maybe, don't really know. How many miles on the car?
Some, certainly not all, ways a 12 volt battery fails it has very low voltage. The silly DC to DC converter will try to recharge it any time it is Ready. It can use up 5 MPG trying to charge a battery with a bad cell.
What do you think: would it also try to charge overnight, with the car off? @ALS mentions the hybrid battery state-of-charge dropping overnight. Maybe just an abberation??
Are we forgetting that relays disconnect both wires from the big battery every time we punch the POWER button off?
CR94, the big pack stopped dropping over night after I replaced the 12V. There were mornings when I would have one bar? That was freaking me out thinking the main pack had a problem.
