BAHH. battery drain.

Just had halfords give my battery a thumbs up. This saves me £100 but gives me the task of finding whats killing the battery if I leave it for more than 3 days. Ive tested the drain and it seems to be 0.3 Amps. Ive only pulled fuses from under bonnet so I guess its all the others to try next. Did end up spending the £100 in Halfords on a replacement for the alpine radio cassette though so wasn't a wasted journey

£100? I didn't know Halfords take deposits

spalding1968 said:

Just had halfords give my battery a thumbs up. This saves me £100 but gives me the task of finding whats killing the battery if I leave it for more than 3 days. Ive tested the drain and it seems to be 0.3 Amps. Ive only pulled fuses from under bonnet so I guess its all the others to try next. Did end up spending the £100 in Halfords on a replacement for the alpine radio cassette though so wasn't a wasted journey

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That's the same as my 300tdi drew when locked (bonnet switch pressed down), never had an issue with anything even after it was sat for a while.

If I remember this correctly, I think after you lock it and leave it for a while the 300mA drops off to something even lower.

must be a constant drain to kill the battery within 4 days with no use. Would be a great result if the drain was from the radio cassette I replaced. But im not that lucky

1. which AH battery you have?
2. pull the fusible links in engine bay fusebox one by one while a-meter is connected and watch the drain...if no drop of drain start with the fuses..if the drain will not drop much(cos it will drop with the normal drain at a time, around 50mA) then 99% the problem is within the diode pack of the alternator cos there are at least 56 different ways(others than a "serious/total" failure) for a diode pack 'failure' without even notice a big difference in the charging voltage but inducing an up to 1A drain into the system

and in this case the only certain method to find out is by using an oscilloscope Testing an Alternator With an Oscilloscope | Circuit Specialists Blog , it's one thing o be ruled out


....if you find a drop of the drain in one FL or fuse report back which one and i'll tell you more

tried with my tester this morning and following the initial start of about .5Amps it dropped to nearly nothing. I did notice that the quiet space invaders sound from the abs module (think that's what it is) wasn't there. Ive pulled all the fuses in the engine area before and didn't get below .3Amps so will just have to try again when the space invaders are back. Other than that I still cant get my courtesy lights to work with the fob or open door. maybe this signal is shorting out as the connectors under passanger footwell seem ok. Don't see why this should flatten the battery though as I don't get a beep when I alarm with the fob suggesting all the doors are shut therefore no power to the lights. Still not ruling out replacing the radio fixing the problem considering how many wires the guy pulled out.
many thanks for your help. will update if the problem hasn't gone for good.