I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?

I have a BMW 535i and it has the problem of killing its battery mysteriously, I was wondering if people had the same issues with their e34's. Its not the question of a bad battery because this is the second battery that i have installed in the car. The car charges the battery i believe because it runs and drives and if i let it sit for a day after driving it still starts, after that it dies. HELP ME!I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?Hi from France ?



Perhaps it's your clock inside and / or some other little '' machines '' like that, which emptied your battery ? It's just an idea ...



Have a nice day,



Cat.I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?
battery cables or the alternator or the voltage regulatorI have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?you have an amp. draw coming from something. You can remove fuses to try to isolate were its coming from.I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?
My son has exactly the same car with exactly the same problem.



I have tried fully charging the battery (off the car) and there is no problem with the battery.



I have monitored the electrical circuits with the battery connected and there is a constant 300mA drain on the battery. This doesn't sound like much but, even with a 100AH battery, the battery is discharged within two weeks. The only remedy I have found is to disconnect the battery when the car is not in use, very inconvenient because of the location of the battery.



A thought has just struck me. Is that you J?I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?Even when you buy a brand new battery for your car, if the place you bought it from doesn't regularly make sales of batteries then the batteries they sell go flat as they've been on the shelf for too long, and once they go down to 0 volts they're never efficient again.

I had battery problems with my old E36. It sat on the drive for most of the week and then sometimes when it came to starting it, it would be completely dead. I then had to jump start it from my other car.

It was dead because the alarm was draining the battery through the week and nothing was charging the battery.

Car batteries only last 4 to 5 years depending on how often they're used. This is because a chocolaty residue builds up in the battery and kills off the charge.

I think your car will benefit from more requent and longer use and so give the battery more chance to charge.

You could try charging the battery up, as I did, and checking its normal voltage which should be 12V and when the engine is running it should reach about 13.8V.

Check the voltage of the battery using a fluke.I have a 89 BMW 535i and the Battery dies mysteriously. Any suggestions for areas where faults would be?
try the interior and boot light,central locking and the general module is a common power drainer if at fault.