Greetings, I am new to the forum so thanks in advance for any advice you all can give me (as this is driving me crazy).

I have a 1996M 525i SE Touring Auto that I bought just over three years ago, it had done over 90k miles but had full BMW history and was in pretty good condition. Shortly after buying it the battery died and when I checked it was not an OE BMW battery (and my local dealers wanted over £100 to replace it - plus they insisted that they needed to see the car in order to tell me the correct model) so I decided to fit a non-BMW replacement. I did go for the heaviest duty one I could get my hands on, the car has A/C as well as being an Auto and I can imagine it being a bit 'hungry' on the electrical side.

After about a year the battery died again. I would come out and the car was dead and despite an overnight bench charge the battery would die in a few days again. So, another new battery went in and all was well - or so I thought. The truth is that I am now onto my fourth battery in three years, although I admit they have all been non-BMW ones (but I can't see that making a huge difference). The most recent one was purchased in November last year and it has already started to play up. I have had the car checked over three times by various different garages (including Sewell) and all claim there is nothing wrong with it. Alternator is charging properly, no current drains that they can detect.

Does anyone have any suggestions? Does this ring any bells with anyone? Maybe it is just the duty cycle on the car which gets used for a lot of short runs and only goes out of town once a week (30-40 mins each way). Any comments would be helpful.

Thanks!

I've seen a similar problem on a diesel vw passat, it turned out to be a leaking diode on the alternator

good luck

Nigel,

I was thinking that throwing a new (or probably reconditioned) alternator onto the car might not be a bad idea. Sounds like another reason to give that a shot.

Thanks!