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Old 10-04-2012, 02:50 PM
avoiceoreason avoiceoreason is offline
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Location: PA
Join Date: May 2010
Posts: 64
Mein Auto: '07 650i convertible
A couple of battery questions

I am getting an "increased battery discharge" warning.

I have gotten this a couple of times in the past. Once it was something electrical not letting the car sleep properly, another time they told me not to use bluetooth, the last time they told me my driving patterns were the problem but then discovered some issue with the battery itself (can't remember what) and they replaced it under warranty.

So that was about a year ago. Had no problems until the other day. So a couple of questions.

1) I know the alternator doesn't engage (and therefore charge the battery) under a certain speed. What is that speed?

I have a short commute and touch maybe 45 for a few minutes at best. Of course I wasn't commuting at all prior to the last month and the car would go days at a time without being driven (which you would think would be the problem) - no problems - then when I start driving more regularly I get the error.

2) How far away from the car should the key fobs be? And is this a real issue or tilting at windmills? Mine are generally tossed in a bowl about 20 feet away.

3) After the issues the first time around, I have never again used the key to put the top down since this puts strain on the battery. But if the battery doesn't get charged even with the engine on unless it is travelling at a certain speed, is there any difference in battery strain putting the top down with the key vs. when the car is idling?

I have been charging the battery every other night since getting error, but the charge doesn't seem to hold for more than a day or so.
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