850i - Batteries

I just saw another 850 today and the owner said that the batteries die if you let it sit for about a week? Is this a common issue plaguing the 850i? Thanks

Originally Posted by cmellios16

I just saw another 850 today and the owner said that the batteries die if you let it sit for about a week? Is this a common issue plaguing the 850i? Thanks

No,
My batteries stay charged for quite a bit - the car sat for almost 6 weeks at one time and the batteries were just fine. Now, if you have crappy batteries (mismatched,old, worn out, won't hold a charge), then yes, they will NOT last more than a few days....

Yeah that's what I'm guessing. Now, since were on the topic. How much money is it going to cost if I buy two brand new ones? And along with that, the owner says he has the BMW chip installed. What does that do? Is it like a performance chip?

Here are some choices:
AutoZone Duralast 49DL: Those should run you around $95-$110 each
INTERSTATE MTP-93: Those are a little bit more, but are a very good battery (depending where you go, figure around $135-$150 each)
BOSCH and SEARS make the same size battery at a higher price.