Originally Posted by
rebel.ranter
You could get an "Energy Diagnosis" done on the battery which would give you a good view of the battery condition. A good independent would be able to do this for you. What year is the car? The batteries in these cars seem to last 6-7 years before giving out, the e6x & e9x models seem to be load heavy when it comes to the batteries & the ideal batteries for these cars are the AGM type, the deep cycle battery. The OEM BMW AGM battery is black & the OEM BMW lead acid battery is white.
The lead acid version will give up sooner.