Wayne Smith

Batteries use chemical reactions to create current. These reactions slow down when the battery is cold. Therefore a cold battery drops a % of its cranking power. So you were already down 25% due to drainage ... Battery at 75%. Drop another 20% of that and you are at 60%. With the cold your starter motor isn't as efficient. So now maybe you are at 50%. Do you have a new alternator cable with better connections or the older cable? Maybe you are down to 40%, or even 30.

It doesn't take much to get into trouble. By four years, any battery is due to fail. The chemical reactions are one way, forming a precipitate that will not return to solution. The constant daily 1 amp hour drain destroys these batteries over time.

Technology has improved so the plates don't warp (as badly) and short, and the precipitate is less likely to contact the plates, but the chemistry remains the same!

7391420

Had a similar issue with my 08 c2

Ended up being the alternator. The PO didnt use the car much and essentially flat Spotted the alternator. It was a total intermittent problem, and replacing the cable and battery didn't correct it.

Interesting conversation on locking vs locked car storage. what I understand from talking to a few Indy wrenches is that after a few hrs, it makes no difference, ie- the car keeps several systems active for several hours when the car is unlocked , but then puts them to sleep.
Incidentally- over the past 2 weeks while we had salty roads in the northeast I didn't use my car. Today roads are dry and it started right up

PRM97401

My car is 100% stock... no toys, no gizmos, no aftermarket add ons. She is my daily driver and the battery is 10 months old.

Chaos

The starter battery alternator harness guaranteed

PRM97401

The dealer isolated the fault/drain to the PCM and it was replaced under warranty. Only time will tell if the issue is really resolved.