320i Convertible Battery Drain

[M3KUK]

As above, the battery keeps going flat on my Convertible.
There is an alarm fitted, but even if I leave it off it drains flat if not used for 3-4 days. Any tips?

[Stefan on probation]

I ripped out the after market alarm and it cured the problem, it was draining the battery even if it wasn't in use.

You can test the circuits and see which one is draining the battery with one of theses,

http://www.ebay.co.uk/itm/Automotive-Ca ... 2548.l4275

[Brianmoooore]

Get a meter, measuring current, in series with the negative battery lead, and measure the current drain. If it's excessive (above around 60mA), pull out fuses 21 to 28 inclusive, and replace them, one at a time, and record what effect this has on the drain. If that doesn't produce useful results, disconnect the two or three smaller wires connected to the battery + terminal one at a time.
Open a window before you start - some remote locking systems (one you may not even know about), lock the doors when power is reapplied after the battery has been disconnected.

[M3KUK]

Thanks, I have ordered the tester, will let you know how I get on.

[mikemike]

I have the same problem so I fitted a battery master switch , sorted the problem out for me