Re: I just drained my battery :( (archive)

How old are the batteries? Were they both replaced last time or just one of them? It's really important with our cars to replace BOTH batteries at the same time. If one is going sideways it will take the other (stronger) battery with it (don't ask me how I know this!). The batteries can't be isolated (although that would be a great feature). The complexity of the the 8's onboard electronics makes it very battery dependent so it's critical to keep them in top condition and to replace them sooner rather than later when they start to fade.

You can check the specific gravty or (probably easier) take the car in to a shop and have them load test the batteries. That will tell you quickly what's going on.

Sounds like you're familiar with the OBC unlock feature - what does test #9 give you for a voltage reading first thing in the morning before you try to fire the car up? Once you're started check again under way to see if the batteries are charging up. Again, using OBC test #9 and with the engine off load up the system with headlights, foglights, rear window defroster, fans, and so on and see how fast the voltage drops to 11.5 to 11.8 and how fast it rebounds once you shut down all the accessories.

Sounds like you retained enough juice to run your computers. Be sure you dump all your fault codes before disconnecting both batteries together or you'll lose any stored info.

Re the oil thing - not sure if you mean 20% left on the dipstick or on the interval lights - if it's the dipstick I sure wouldn't let mine run that low.

Derek
'93 850Ci - L/G

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