Quote Originally Posted by DamienOS
So Iam gonna buy a new battery for the M5 as I've noticed the battery currently in the car looks like a cheap piece of crap

Having done a load of looking about no one seems to have the proper spec for the battery

Main dealer want 303e plus vat for the standard one which as far as I know is made by Exide

There seems to be a S5 series battery from Bosch that's the dogs bits for them

Anyone in the higher engine 5s or even 3s gotten. A battery replaced recently and how much and where ?

The battery in her is on 720cold and Iam told it should have a 900 in her ...
I presume you are talking e39?
I had a 720 in the 540i before, car was struggling a bit to start. So I can imagine a M5.
Halfords does the excellent Yuasa battery brand for about 115 euros with the Axa card discount or so.
900amps/100ah
Have it in the 540i, works very well and 5 years warranty.

http://www.halfords.ie/webapp/wcs/stores/servlet/product_storeId_11101_catalogId_15551_productId_73 4844
_langId_-1_categoryId_212578