E36 3i8i(A) 1997 Battery power discharged

[Buck7175]

Dear Sifus,Please help..The battery went flat after about a week lay off. I contacted AAM personel who checked and had the battery replaced.After about a week it happened again and i requested for the battery changed. I had my regular mechanic checked and replaced a recon alternator unit suspecting it could be the caused but same siituation faced. Recently bought a new Century battery( Dins 66) It only last for 2weeks. I have charged the new battery and have my mechanic check the wiring starting from the alternator. He suspected the wiring done at the audio system. He disconnect it from the radio. However, the battery lasted only about 10 days. Currently, my beemer is at rest in my home garage.I am at lost please help!

 

[jeffreyewe]

Try to observe if there are any lights on in the cockpit once you've locked the car, go to the back and see if the brakelights are still on once you've set the alarm. Sometimes, the brake switch could be the culprit as the plastic connectors gets brittle overtime thus sending the brake on signal.

 

[Buck7175]

Thank u for ur advice sir. I made it a practise to ensure that all lights in the cockpit switched off incl brake lights and main light are off too before leaving the car.However, my car main switch light is a bit loose but i revert it to '0' after using the lights. Not sure whether that is the culprit before i replaced it. Hope to get more lights on the issue appreciate it

 

[zbasheer]

Suggestion.....Your bootlight may be on when the bootlid is shut. So, why don't you try to dismantle the bulb for a week or so and observe...

 

[Buck7175]

Thank you bro will do that..I have charged the batt on thursday and was driving around on friday morning but by evening the batt failed me again.

 

[jarance]

Thank you bro will do that..I have charged the batt on thursday and was driving around on friday morning but by evening the batt failed me again.

Can you get a clamp-on meter and check what is the current when the ignition is off?

If the current is greater than 500 mA, there is a possibility that some of the equipment did not go on standby mode.

 

[aidilj]

Can you get a clamp-on meter and check what is the current when the ignition is off?

If the current is greater than 500 mA, there is a possibility that some of the equipment did not go on standby mode.

On top of that start removing fuse or component to nail down which is the current sucking component. See here : http://www.bmwclubmalaysia.com/forums/showthread.php?42221-Some-electrical-questions-for-my-E30

 

[megatniza]

another option .
had a similar problem ...
as our UDM ages , current will tend to leak at various areas .
what my mech did was to install extra grounding , one at the alternator & another one in the battery compartment .

 

[jarance]

another option .
had a similar problem ...
as our UDM ages , current will tend to leak at various areas .
what my mech did was to install extra grounding , one at the alternator & another one in the battery compartment .

megat, yes this might work but it is for the wrong reason.

If you have some leakage in some of the component in the car, extra grounding of the alternator and battery
will reduce the resistance to the body. This will in turn allow more leakage current to flow to the ground.

However, this solution will still worked because having less resistance between the alternator and the battery,
the charging current for the battery would also be increased. This will indirectly charged the battery more.
If the battery is charged more, then it will have more "reserved" power when the car is switch off.

 

[Galaxy7]

read this bro, hope it can help u.

http://forums.bimmerforums.com/forum/showthread.php?t=1067269