Originally Posted by swamp2
Just to close the loop here - a brief update. I finally went back to my stock battery. I had a low voltage warning until my first long-ish drive. Since then it has been gone and there are NO problems with CA nor with the date/time memory. Problem cured as I much suspected it would be.
Does anyone know of a battery by BWM or their battery supplier that is lighter, the same form factor and about 60 Ah or so. This would be a great replacement for those of us in warmer climates looking to save weight without any reliability problems.
The OE supplier for BMW automotive batteries is Exide
I would suggest a battery used in the MINI COOPER. (BMW satellite brand)
It's rated at 55Ah's, weighs approx. 35 lbs., and it's BMW OE quality.
You are looking at approx $190 /w/ tax depending on where you buy it.
Here is the factory part# for the MINI COOPER (Exide) 55Ah battery:
$176.25 list price as of 1/09
I suggest this for quality (proven OE performance), convenience (available at any mini dealership in the country), and the light weight package.
I used this battery with great results in my E46 M3 for nearly 3yrs. without any memory/charging issues.
I strongly recommend that you consider this route, as you won't find many other viable alternatives. (despite all the marketing claims out there from a variety of aftermarket lightweight battery companies)