when parked, the car must/should be connected to battery charger that NOT only trickle charges but provides full power (ie 13.6-14.4v), as if an alternator/battery system would when driving. If your batt craps out during coding/software updating, it could "brick" your car.

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I swear, my cars are like a girlfriend.
Sometimes its a rough ride, sometimes its smooth motorin'.
Sometimes she doesnt like how i treat her and sometimes i dont like how she behaves.
BUT at the end of the day, she loves it when I am inside her.

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'91 850i
'05 X5 4.4i
'09 Clubman S