Battery Discharging

[kingfu]

I only drive my Golf once every week or fortnight and the battery has started dying. Charged it up a few times and the same thing. I've hooked up a voltmeter and with the engine off it reads 12v, with it on 14v, so would I be right in saying the alternator is fine?

I then tried to test if there's any parasitic draw. I put the voltmeter into 10amps setting, disconnected the negative cable and connected the voltmeter between the batteries negative terminal and negative cable. Gave me a reading of 0.08a. Is this a normal drain with everything off? If so I'm guessing the battery is duff and needs replacing?

[itavaltalainen]

80mA seems a bit high for a mk3 golf.... but give it another go....

this time disconnect battery, connect amp meter, close all doors, push in the bonnet switch and stick it down with tape if you have alarm and lock the car. then wait for a while for car to settle down and read how many mA it draws. A stock mk3 with a correctly wired radio should not draw a lot more than 10-20mA.

If it does unplug radio and repeat test. Should it then come down check the radio is wired in correctly (i.e. ignition and permanent 12 are correct way round and not both connected to perm 12).

[kingfu]

thanks itavaltalaine. When you mentioned the radio I thought that must be it, because the wiring is a complete bodge job where someones connected a different radio adapter.

I set the voltmeter back up and followed your instructions, pulled the radio fuse though and it made no difference, the reading held at 0.08. I then pulled the "interior and luggage compartment lights, cig lighter" fuse and it immediately dropped to 0.02. I'm guessing we have a winner? The thing is everything works as expected on that list?