E39 M5 Batteries

[trooperiziz]

The recent cold weather seems to have sent the battery in my E39 M5 into a nosedive and I had a devil of a job getting her started today after leaving her a couple of days, so i've ordered a replacement. She kicked into life after a few very slow revs of the start motor, and started fine second time round. However I am assuming tomorrow morning to come down to a dead battery. (I don't think it's any more serious than that, as I haven't had a problem before and have left her 3-4 days without starting, and she is 9 years old now and probably still on the original battery)

Anything I need to know about replacing the battery? Any weird foibles I need to know about or is it just a straight pull out/drop in job?

IIRC on my Phaeton you had to do some weird electrical voodoo steps if you wanted to replace both the batteries at the same time, but i'm assuming the Beemer is much more sensible.

[rassi]

It is a simple job to replace it, but make sure you get a battery of a similar capacity (850 CCA IIRC) as the 5 litre V8 is fair old beast to get turning + the abundance of electrical gizzmos that needs sufficient juice.

I got mine at BMW for €200 but they can probably be had at half that if you go for a non BMW one.

[trooperiziz]

rassi said:

It is a simple job to replace it, but make sure you get a battery of a similar capacity (850 CCA IIRC) as the 5 litre V8 is fair old beast to get turning + the abundance of electrical gizzmos that needs sufficient juice.

I got mine at BMW for €200 but they can probably be had at half that if you go for a non BMW one.

I went for a S5015 Bosch with 110 Ah and 920 CCA, so it should be more than capable for the job
£120 including vat and delivery. BMW quoted me £160+vat for the OEM battery.

Edited by trooperiziz on Thursday 17th December 16:06

[DA75]

After 2 replacement BMW ones I gave up and bought the Halfords equivalent which has been fine - 5 minute job to replace

[oltarmac]

ive just fitted a varta silver oem spec,5 year guarantee, £85.
piece of cake to swop over.