BMW: 735i 1998 BMW, cable connectors, electrical problems

Question
Josh

You seem to be going along the same lines as my father suggested.Initially I noticed that the cable connectors at the battery were loose on the posotive end. My father seemed to think that this may mean that the alternator would not see a full load and would try to overcharge the battery but perhaps become faulty itself which would then start to affect future batteries.

The alternator has not been replaced but the engineers (not BMW engineers) have checked that the battery is charging ok. The thing is that the situation seems to have got worse even with a new battery being fitted where a charged battery only lasts a day (sitting outside my place of work).

As i said , my friend has exactly the same problem and has had his car in a workshop for 8 weeks; also I have heard of another person who simply gave up and swapped the car.

I have remnoved the bulbs in the glove box and the boot to see if these are drianing but in all honesty the situation seems to have got worse rather than better.

I will see if my garage can test the alternator and follow that route at this stage.

Thanks for your help.

Mike




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Followup To



Question -
Josh

Apreciate that you may not know this car as well as the earlier models.

I have a problem with the electrics of my car.

Initially the battery went flat when I left it for a couple of days. Since then the battery keeps going flat - I am on my third battery now. My friend has the same problem and a main dealer has had his car for 8 weeks.

Have you heard of electrical problems like this. The battery only lasts a day now.

Mike
Answer -
Mike,
 This sounds really odd, I first suspected that something was draining the battery even though the car was off.  But since you have been driving the car, the alternator should be recharging the battery even if there is something draining it.  Usually a glovebox light will stay on and over a few days it can drain the battery, especially if it was already week.  But if you drive the car regularly then the alternator should replenish the spent charge.
 Since you have replaced 3 batteries that makes me think it's something else.

 Have you checked the alternator?  If the alternator is not working 100%, then it will eventually drain the system.  So after you placed the battery with a new one, how long before the battery went dead?

 Thanks,
 Josh

Answer
Mike,
That's what I would do.  Make sure the CHECK THE ALTERNATOR, and NOT the battery.  Most places will look at the battery and if it's charged they think everything is in working order.  If your garage doesn't have a machine that checks alternators, take it to Autozone or something they usually will do this for free.
 Make sure that you are getting MORE than 12Volts from the Alternator.

 I think that's the problem...or something is SERIOUSLY draining the battery.

 Good Luck,
 Josh