Intermittent Parasitic Drain

[bcredliner]

I read that the battery was checked but---how old is it and was it load tested? I have been mislead by battery tests more than once. Combined with how hard slow drain problems are to solve, I do a real world test of the battery. In your case I would disconnect the battery for 4 days and see if it will start you X when I hook it back up. If you can check the voltage it is holding you can eliminate the battery sooner than 4 days.

Again, because of the difficulty finding a slow drain and to prevent buying a part I don't need, I would rather disconnect the electrical connector(s) to a suspected cause of my frustration than remove the fuse so the wire(s) to that part is eliminated as a drain source at the same time.

[Aldous]

It was a load test, it passed but i didn't get any details. I've had the car for a year now and the shop said the battery wasn't the original (though it was BMW, not sure how they know its not original), so i'd guess the battery is 2-6 years old.

it's been run down so many times now though through this process i'm sure it's wrecked, it died the other day after 20 minutes with the door open while i was loading it up for the weekend (likely wasn't fully charged but still...)

so i'm going to get a new battery, i dont really want to spend big money on a BMW battery if the problem is still there and will lead to a short battery life, but dont really want a non OEM battery since it sits inside the vehicle cabin...

i'll try just checking the battery voltage, disconnecting it and seeing if it drains on its own, that should be quick enough, thanks

[bcredliner]

Aftermarket battery is fine as long as it is very close to the performance of the BMW battery and if and vents outside rather so the cabin is safe.

[JCL]

Originally Posted by Aldous

Time to try some different fuses I suppose

I suggest you do the current draw test properly, so that you identify which component is causing the residual current draw (and likely preventing the vehicle from going to sleep as it should. This is what actually flattens the battery most times).

Here are a few links. You need an ammeter, a small jumper cable so that you can keep the vehicle powered up while you disconnect the battery cable, and some time. It is a pain, but it feels good when you find the actual cause.

http://www.xoutpost.com/bmw-sav-foru...4-dead-x5.html

http://www.xoutpost.com/bmw-sav-foru...dies-fast.html

Post #42 in the second link contains a good link as well.

Jeff

[Aldous]

well the battery died after charging it overnight then driving it to work and parking it for 4 hours, so i took it into the shop.

battery failed the draw test this time, put a new one in, and no problems so far.

haven't left it long enough to see if there really is a parasitic draw or if the battery was bad all along, just not quite bad enough to fail the draw test the first time.

thanks for the help

[Doru]

If the battery dies like FSU draw, but not FSU - if you have the OEM CD changer, this is also known to do it.