Battery drain and going flat.

[tim falce]

I have a 1999 3ltr diesel which has suffered with the battery going flat more than it should, this has been a problem all the 4 years I've owned it. It's now had two or three batteries. The problem seems mainly if I leave it parked up for more than a few days and It's worse in the winter. I parked it up on Monday evening and today the battery was quite low and it only just started although It's always a pig to start when cold. I've tested the battery and according to the test meter it's fubar. With the engine ticking over I'm getting 14 volts, 12.5 with the engine switched off and the drain with the alarm on is about 70ma. Has anyone got any experience of these or any ideas what the problem might be. It's an FX model with only one battery, when I bought it it was fitted with a 650 CCA which I have replaced with a larger 700CCA battery. Any help welcome.

 

[Euan McGilp]

Afraid I can't help with the cause - that should be picked up by the excellent & knowledgeable members on here. However, on a practical note, I use an 'Optimate' unit (check Ebay etc) which has tails permanently connected to the battery & a semi-sealed (rubber cover) socket to connect to the charger unit when leaving the truck for a while. Obviously this will only address the symptoms & not the cause - but mine only began to drop battery charge after I had an alarm fitted. Have had the truck since 2003 & only on 2nd battery...

Cheers,

Euan

 

[helen07]

Had this on a boat once and all attempts to cure it failed and so the problem was left and lived with for years . Until a deck light was smashed and replaced with a new unit . It was a while before we realized the battery problems went away when the light was changed . The electrician said it was probably because the old wiring was worn through in places and where it was touching bare metal it was leaking power away in tiny amounts . I personally would have thought this would just instantly short out the circuit but the electrician assured me it was a common enough problem . Hope this helps ?

 

[tim falce]

Thanks Helen, the problem is being lucky enough to find the fault if it's a broken wire. I had a similar problem on a Vauxhall Corsa, it bugged me for about 3 years until it happened when my daughter was driving it, she called the AA who eventually tracked it down to a £3 otter switch in the head not turning the glow plugs off.

 

[danial76]

the problem is being lucky enough to find the fault if it's a broken wire.

 

[Andrew T]

Get an ammeter / multimeter in line to see what your current drain is with the ignition switch off. It should be just a few milliamperes at most, for alarms, clocks, etc.

Once you get a reading you can systematically pull your fuses to see which circuit has the current draw on it and affects the reading.

If none of the fuses affect the current draw then the fault must be between the battery and the fuse box.

The trick is to be systematic so you are eliminating areas of fault

Good luck, but once you identify the faulty circuit you have a chance of tracking the fault

Cheers A

 

[SpinDrift]

You can get one of these leads for your multimeter from Maplin: http://www.maplin.co.uk/car-fuse-adaptor-lead-set-217881

You pull the fuses out of the fuse box one by one and plug this in instead to see what current is being drawn on each circuit. Process of elimination.