Alternator issue?

[imi7]

Lent my 4.6is to a mate whilst I'm away. He called me today to let me know that the car struggled to start initially, and warning lights flickered briefly - problem now is the damn battery light stays on, even though the car drives fine. He drove the car for 20mins - turned off for 30 mins then restarted - all good except the battery light remains on !!!

Since then he left the car for 2 days and he told me it started ok 1st time of asking, but battery light is still on.

Weird thing is that 3 weeks ago I turned the car off but the Auto headlights stayed on, until I had to restart/switch off the car a 2nd time.
I can't sort out this issue until I return at the end of Feb, so 2 questions:-
- Is it safe to drive the car?
- does this sound a battery/alternator/some other issue?
Cheers

[imi7]

HI. Just to add, if it is not an alternator issue and all seems well, is there any way to reset the red battery light?

Thanks.

[imi7]

An update - after 1 week the car does not start, but the lights seem to be working ok (for now). Decided to replace the alternator and saw the folowing on Ebay - which one would you choose? Thanks.

BMW X5 4.6is E53 £220 WATER-COOLED ALTERNATOR Bosch OE 150amp 2A167 ABBCO Luton | eBay

or

RTX Alternator For BMW 5 & 7 Series & X5 | eBay

[Drkenigma1]

I have had this problem for the past year. I had the alternator rebuilt and every 2-3 months I either have the battery light, and/or the deadly triangle (abs/red brake light/dsc). It is the alternator. New alt is about $900 for the part or 450 for a rebuilt from a auto store that they have to order. At this is for a 2001 e53 water cooled. Easy to replace but extremely expensive.

[imi7]

Thanks Drkenigma1. Would you recommend buying a new alternator in this case or to buy a rebulit one? - the Ebay links above show sellers that have 100% +ve feedback in the 100's so I'm thinking of buying a Reman alternator.

You mentioned that your bettery light came on every 2 months - how did you get rid of the light?

Thanks.

[Drkenigma1]

Well funny that you should mention that. I now have the battery light on, which means a charging problem. I called several BMW dismantlers and local shops. They told me that this cannot be rebuilt. I am like you and have to buy one from somewhere else. The only way out of this pickle is replace it from a dismantler or retailer. I am going to buy on from Ebay. My light when out when the alternator is replaced and battery is charged. I think that my coolant leaking problem (valley pan) may have something to do with it because it is water cooled.

[imi7]

So will you be buying a new one or still sticking with a reman, as you had problem with your rebuild? I am tempted to buy new one, but the price tag is very steep - not sure yet!