[estankov]

I have a 2009 E91 (328xi) 110K miles auto in decent shape. I installed a new battery about a year and a half ago (old original was getting sluggish). Interstate H7 registered when installed. No issues. About a week ago, I sat in the car for 1 hr on a call, key in ignition, car started for a few minutes to warm up, then turned off. By the end of the hour I got a low battery warning and could not start. I am not 100% sure but I MAY have had the AC on low, while in the call (without the car running). This is the beginning of the drain issues I have been having, no drain before that.

I got a jump from a friend (pretty quick as soon as we connected the jumper cables) and drove for a few days with no issues. Then the car died again in a parking lot after a 10-15 min short drive. Jumped again, got a NOCO charger at home and charged the battery full. After that I left the car sitting for 5 days went on vacation, and when I came back it was still fully charged and started no problem. Looks like if I charge the battery and lock the car, car goes to sleep, there is no slow drain overnight etc.
It seems like the problem is when I plug the key in the ignition but dont start the car right away, something drains the battery pretty fast. Within minutes it drops to around 10V and not enough juice to start. Error code CC-ID 229 Battery Charge Low

Things I have checked:
- Battery. Autozone guy checked it with his tool, showed up Normal. It charges pretty quick once low (within 15 min) and holds charge around 12.5-12.7. Its registered by the mechanic that installed it. In warranty 30mth. Battery compartment is dry, everything looks like new
- Car does go to sleep in 15 min. Not a Comfort Access, Base model
- Alternator (original 110K miles) with car running shows 14.9/15 volts consistently. Maybe a bit high compared to others on forums. I disconnected the power and used diode meter on positive terminal and alt casing it showed 584 in one direction and "1" in the other, which I think means that the diodes are ok. Original alternator, so I assume voltage regulator is old.
- Unplugged fuses 06,77,88 (AC symbol) all together and individually, no change still drain.
- Unplugged fuse 14 for stereo. No change still drains.
- Replaced the climate control unit with another used one I had. No change, still drains
- Unplugged climate control, unplugged the FSR on the blower fan. No change. By the way my climate control on the fan acts normal, all the levels work. Doesn’t exhibit FSR issues.
- Ground cables. Some weeks before the battery drain issues started, my ground cables were pretty much rotted through, fell apart as I touched them. Car would intermittently not start. I replaced both cables with aftermarket heavy duty rubber coated cables (in engine compartment and under the driver side). I also changed the starter (unnecessary - before I figured the problem was the ground cables) I drove the car for a while after that with no issues.

Other notes
- Car has dash warning on the Angel Halo lights - both bulbs are gone, Has been like this for a long time before the battery issues started.
- Occasionally when I don’t drive often I get the key fob low battery warning, goes away after I drive for a longer period and the key gets charged.

Any advice to narrow down next steps would be appreciated.