Hello:

Thanks again for all your comment. First I bought a Schumacher 50-10-6<>2 AMPS charger (SE 5212A-CA). I tried to charge my old battery unfortunately the battery is no longer able to hold electricity. After it is fully charged, few mins later the voltage keeps dropping to around 11 Volts. After several attempts, i conclude the battery is dead. As for the charger, i will keep it for future use. It has a jump start feature so i will need it someday.

So i decided to get an Interstate battery which has a slightly higher CCA then the standard battery from BMW. There is an interstate battery dealer in my area so i only paid $191.95. The battery is slightly wider than the original one but it fits in the battery compartment. Looks like the battery compartment is designed to accommodate 3 different battery sizes and this interstate battery fits the medium size.


Here is the spec of the battery (Interstate Batteries | Every Battery for Every Need)

Retail*: $191.95
List: $218.95

Mega-Tron Plus
Mega-Tron Plus 49/H8 Automotive Battery Six-Year Performance 730 CCA
30 Month
Free Replacement
Six Year
Performance Warranty
730 CCA (Cold Cranking Amps)
Part # MTP-49/H8