bmw e30 battery dying problem any ideas

[beavere30]

hi anybody know what could be causing my battery to die on my e30, the alternator charges it fine just when left it dies,iv cleaned off all the earths. i then took to an auto electrician that didnt have a clue, he decided to charge me £33 for disconnecting the alarm which i didnt want doing and that didnt solve it. hes also trying to tell me that the battery is no good which is brand new and so were the previous 2 batteries, which it still had same problem with, anyone with any ideas would be much appreciated
many thanks brett

[dodgym3]

hi mate

as poor as the auto elec guy seems to have been my mate had the same problem on his 320 e36 and chopping out the alarm did the trick, if its the original bmw alarm they go funny after a while also check the start motor connections are not arcing out.

[beavere30]

ok thanks for ur reply mate it sounds quite interesting actually because it seems to either start or it doesnt if u know what i mean, it never tries to start and fails. its either all or nothing
ill check it out on a dry day
cheers brett

[E30M3SE]

Looking at your opther thread about CDL problems and locked boot I would be checking the CDL control unit, which can be found behind the drivers footwell speaker. Known for filling with water, corroding and causing problems.

Wire a ampmeter in series with the battery and check the current drain.

[beavere30]

ok mate cheers ill have a look at that, i have had an amp meter on the job but it shows very little drain basically nothing
cheers brett

[E30M3SE]

beavere30 said:

ok mate cheers ill have a look at that, i have had an amp meter on the job but it shows very little drain basically nothing
cheers brett

How much is very little?

What figure is it showing?

[beavere30]

well it was auto electrician that checked it and he said it was basically nothing, jus like standard for any car