E30 CAR BATTERY KEEPS DYING ON ME:s

[j4ttluv]

HI got a e30 bmw and ive had to change the battery like 3 times in 1 month because it keeps dying on me if i dont start it for 2-3 days and it shouldnt die just because i havnt driven it for 2-3 days its mainly been happening since i removed my headunit from da car and disconnected the wires from the head unit but could that be the problem? if any one knows on what it could be please let me kno..also does any one hav a diagram or picture of where the alternator is located so i can check that cuz i cnt seem to find it..thanx!

[smithy318i]

Check the obvious things like the boot light and glovebox light.


then.

First measure the voltage across the battery with the engine running, then stop the engine and loosen but do not remove the battery negative connector.
Put your meter on to a current range of about 2A, connect the black lead to the earthing terminal on the RH suspension turret, and push the red probe down through the middle of the battery clamp into the middle of the top of the battery terminal pole. The meter will still read zero. Now lift the battery connector up off the pole, and the meter will give a reading. Switch the meter to a more sensitive range, and measure the current. Lower the battery clamp back onto the pole and remove the meter.
Before you do this, make sure that a window is fully open, as some cars have long abandoned alarms which can activate if the battery is disconnected and reconnected, and activate the central locking.

the reading should be more like 30 - 50mA. Anything more than 90mA needs to be investigated by pulling fuses.
If the reading is normal, then the alternator diode might be duff.

[Speedtouch]

Could be the cold weather - batteries hate it! Alternator is mounted down by the front of the engine, driven by a belt so you can't really miss it (large cylindrical thing with cables coming out the back.)

May be that your battery is on its way out. Unlikely that removing the head unit would cause problems unless you've left a wire bare and it's shorting out on something but the car would probably have gone up in smoke by now if that were the case

[tomze30]

Read this through carefully, it should get you closer to solving the problem:-

http://www.e30zone.net/modules.php?name ... highlight=