X3 battery recommendations

[ashori]

I left my x3 parked for 3 weeks, and came back to a completely dead battery. I jumped started it, and drove around for 20 minutes, and found that I could start it up, but after driving around some more, it would not start up again . I've managed to jump start it again, drive it around, and then was able to start it up again... but I'm guessing that the battery is on its last legs.

Unless someone has some suggestions on my prolonging the life of the battery, I'm wondering if anyone could recommend a good replacement (I've got the '04 2.5i).

[OldHotliner]

I have now 90Amp AGM battery (black one).
I use parking heater everyday and everything is ok.

Dealer has this size for e70(for example)

[ashori]

Thanks for the info. I ended up getting the diehard battery (size 49), from Sears, and almost everything works (side mirror keeps moving around for no apparent reason; but I've heard that the X3s tend to act a little funny for a few days after replacing the battery, so I'm keeping my fingers crossed).

As for the heater, I live in Texas, so I'm guessing I won't need that. I did order a smart charger from Amazon, and will try that when not using the vehicle. The reviews online claim it can double the life of your battery, but the proof of the pudding is in the eating.

[Flyer1]

Be sure the float voltage of the charger you bought meets the battery manufacturers reccommendations.

I kept a small Battery Minder (model # 12117) on an AGM (absorbed glass matt) battery that I didn't use that often and the battery had to be replaced in a couple years. The charger's float voltage was ~13.4 volts and I found out the manufacturer recommended 13.05 volts. Others were getting 5 or more years out of their battery. At $225 for the battery, It was an expensive lesson.

I keep a Battery Tender on my motorcycle battery. Its a standard flooded lead acid battery which can handle a higher float voltage. The motorcycle battery is several years old and so far I have not had any problem with it.

If the float voltage of your charger is higher than what is recommended, you might consider putting the charger on a timer, like what is used to turn a light on and off. If the battery is fully charged, you probably don't need to run the charger for more than a couple hours a day.

The TX heat is hard on batteries. Also, lack of use results in slow discharging and sulfation. This will shorten a batteries life because when the plates sulfate you lose battery capacity. That is what the smart chargers should prevent and thus extend the life of the battery.