jsal

I replaced my battery with the correct model (hard to find) but not from BMW.

After replacing the battery, you have to tell the computer that you replaced the battery as it flags low battery problems and can shutdown systems if needed.

However, when it is cold out (I know, California does not get cold), but if it is down in the 40's in the early morning or late at night, and the car is cold, for the first few minutes, when I shift and the RPM's drop, my radio cuts out for a brief second. An even more rare situation is getting a dynamic drive error.

When it is cold, I am doing very slow accelerations.

We do not get conditions such that it is an everyday occurance and once the car starts to warm up, the problem does not exist.

I talked to my BMW SA, and he did not have any knowledge of such a problem besides resetting the system to tell it a new battery was installed. It is very hard to duplicate, so I am hesitant of having them spend a lot of time and money trying to trouble shoot.

Even though the battery is the correct model and has plenty of power, I am thinking of buying a BMW battery and trying it.

Any input/advice would be much appreciated.

luigi524td

I suspect you have a charging or electrical problem that contributed to or caused your battery failure. Failing to correct the root cause may have resulted in your new battery also going dead.

jsal

Sorry, may not have been clear on that. My new battery is fine. Plenty of power. Leave it for a week or more when I am traveling and no problems and no noticeable effort in starting after that period of time.

The old battery was definately a tired battery. Starting about 6 months prior, I had left it for 2.5 weeks during a trip and it was almost dead. It would charge up fine, but as time went on, it would be almost dead after 3-4 days.

But your electrical suggestion is my other thought in that the alternator/regulator, when cold, maybe flaky.

EuroCarFan

Hey jsal! Where have you been buddy? Glad to see you're still active.

Coincidentally I just got a lightweight racing battery to replace my stock one. It arrived today. Hopefully I won't have any problems with it.

When you say you have to reset iDrive, can that be done by anyone through iDrive or do you mean BMW has to do it with some kind of update?

jsal

Just been way busy with work and have not had the time to be to active.

Has to be done by a dealer. Don't think you have to do it by just changing the battery, only when you had a weak battery.

I guess when you start getting low battery issues, the computer starts shutting down aux systems to make sure the engine, suspension, steering and braking have power. It remembers when this condition happens, so you have to tell the computer you have a new battery and erase it's memory.

PM me if you have any weird issues.

BTW - NICE ride. Like the wheels and upgrades.