why my new battery draining

[rdarvish]

My 2003 530i did not start a week ago after sitting in parking lot for a day. I jumped it and took it home. the next day the battery was drained agian. So I bought a new battery and the car started without any problem. I checked the alternatore and it was charging 13.8V. But over night the new battey was drained agian.

Any ideas why this is happening?

Thanks

[witeshark]

Possibly a bad relay is keeping something connected to power even after the key is off. A check of the trunk and interior light switches may help.

[bimmernut]

Originally Posted by rdarvish

My 2003 530i did not start a week ago after sitting in parking lot for a day. I jumped it and took it home. the next day the battery was drained agian. So I bought a new battery and the car started without any problem. I checked the alternatore and it was charging 13.8V. But over night the new battey was drained agian.

Any ideas why this is happening?

Thanks

I have an 06 525xi (58,000) with the same problem. I bought a new battery and the battery was draining out after 4 or 5 days. I tested the alternator and was also giving me a good read. I am taking the car in this weekend to have it checked out. Stay tuned I will let you know what they say.

[H2SNOW]

staying tuned ...might be my issue aswell

[rdarvish]

Did you find out why your battery draining.

Thanks

[vmag83@windstream.net]

I had the same problem with my 528 last month. However, mine was draining within a couple of hours. It ended up being the trunk lock actuator which was getting stuck in the open position and allowing current to keep flowing through. You can identify which fuse circuit is causing the problem by disconnecting the battery and placing an ammeter in series from the battery terminal to the cable connector and then removing one fuse at a time until you find the one drawing the substantial amps. Before you disconnect the battery leave the passenger door open until the interior lights go off so that the amperage on the lighting circuit doesn't cause you to identify the wrong circuit as the culprit. There is a more detailed procedure somewhere on the forum. Just search for 'battery drain' and you should be able to find it. Once you identify the circuit causing the issue you will need an electrical diagram to pinpoint the issue further.

[bimmernut]

Originally Posted by H2SNOW

staying tuned ...might be my issue aswell

Ok guys. I finally got my car back. It turns out that my alternator was not charging the battery. I orginally took it to Auto Zone to have them check if my alternator was working and the machine said it was charging fine. I finally took it to a Mech to have him figure out why and he said that my alternator was going bad. He said it should be charging at 13 something. Anyway he replaced it (thank god for Third party waranties) Now my car is running well and no longer having any issues with my battery draining. He also said other BMW batteries just run out of juice around 55,000 and some last a little longer. But he said in my case I got a bad alternator and still a good battery. Good luck guys.