M5 Battery Replacement

[delussional77]

Dad's got a 2001 M5 and lives in CT. This means extended periods of removing the battery during the winters because snow + m5 = bad news. Anyway. He has lost 2 batteries and is probably going to lose the one he currently he has now. When he removes the battery for the winter he keeps the battery normally stored and then before it goes back into the car he puts it on a 12v trickel charger. Something doesn't seem to be working because the batteries constantly die. He's tired of paying the $200 for the new Interstate batteries. I compete in car audio so I'm very familiar with sealed batteries. Does anyone know any batteries that will make a good replacement for the stock battery? Or at least one that will fit and won't give him too much grief trying to put it in. Thanks.

[FREDPLT]

In my family and in my garage there have been 12 BMWs in the last 15 years. I have always replaced the stock batteries when they go with a DieHard international. Make sure he isn't putting the battery on a cemet floor, that will kill it, make sure it is on wood when he takes it out elevated a few feet from the floor. Sorry to hear about the trouble, but that car is worth some trouble!

[delussional77]

thanks, but we actually do that....we have a battery rack where my dad stores all of the batts from his cars that he can't drive in the winter. Only happens to the BMW batt (can't figure out why). Thanks for the tips, but what can he replace the battery with instead of getting the $200 BMW Interstate battery?

[kassper]

do not trickle charge your batteries. That will overcharge them and kill it. What you need to invest in is a new battery (obviously) and either a three-stage microprocessor-controlled temperature compensating charger...or a volt regulated float charger. Keep the battery on it during the winter and you will be good to go come nice weather. The three-stages can be had for about 60-70 bucks, and the float chargers can be had for less. Pretty much, the three-stages are better because they automatically switch between bulk, absorption, and float. Depending on the batterey, you may be able to go four-stage and also get the power of equalizing as well.

[Bret]

Hello to the fellow M5 owner in CT. Can't help with what battery to use as a replacement, as I've not had to replace mine. I leave my battery in over winter and drive the car occasionally.

Perhaps the guy talking about the type of charger is on the right track.

The drastically overbudget situation with our new house is forcing me to put my M5 up for sale. It's a 2001 CPO car with 52K on it and 18 months left on factory warrany. Titanium Silver with black interior. This car has 2 of the 3 options that exist on these cars, those being upgraded stereo and fold down rear seats. The car is in exceptional condition and I'm looking to get $43K.

Good luck with your battery situation and please email me if you know of anyone interested in an M5.

[FREDPLT]

man 43K, If I could get 24 for my M3 (E36) I'd probably contact you!