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Old 12-05-2011, 01:43 PM
sunny5280 sunny5280 is offline
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Location: Denver, CO
 
Join Date: Feb 2010
Posts: 3,608
Mein Auto: 2007 X5 4.8i
Quote:
Originally Posted by terri_atl View Post
sunny: so you are saying if I get it fully charged, and I run it on weekends, with a good battery it should recover itself say by end of Sunday? What would your extended periods likely be? Surely I don't want to wander on the highways for hours. An idea just came to me, perhaps I should start planning saying a 1-2 months period, document the battery voltage during various times, and this can serve as a documentation if I need the dealer to replace it for free. But of cos it is going to be a fight that I am not sure if it is worth. Then again no harm trying.
When you took your car in for the battery issue BMW noted you were making many short trips. They're claiming these short trips are insufficient to restore the energy consumed from starting the car as well as when the car is at rest. In order to fully restore the battery to full capacity they perform a complimentary charge. Assuming the battery was still good a fully charged batter should have given you approximately seven more months of operation before the warning reappeared. However that was not the case...you received a months operation before the warning reappeared. This to me indicates either the battery wasn't fully recharged or the battery is no longer capable of holding a charge to the degree it once was.

My recommendation to recharge the battery is to bring it up to its maximum remaining capacity. Once the battery is fully charged you can then "properly" (according to BMW's guidance) charge the battery through a combination of every day driving (the short distances which they claim are insufficient to recharge the lost energy) and longer weekend driving (which they claim is sufficient to recharge the lost energy). If you do this weekly and the battery is good you should no longer see the warning. However if you do that to me is a sure sign the battery needs replacing.
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