Mystery Battery Drainage

[OLLIE 26]

like the title says my battery is being drained mysteriously when the keys are out of the car and nothing is on ... what could it be? i need to fix it or i'll ruin my battery

[cainchapman 0]

Car alarm?

[M3 Cab 0]

Had the same problem and it turned out that the boot light was staying on. Just adjusted the boot latch so it pulled the boot back down. Ernst also suggested that it could be the power windows or central lock auxiliarys not shutting off.

[QuickSilver 0]

if you have an amp the remote cable could have come loose and may not be turning it off?

[SA Motorsport 0]

Hi, there are a number of circuits that could be causing drainage.I recommend that you check the voltage being drawn from the battery, at the same time, remove one fuse at a time and then you could possibly pin point the circuit that it causing the drainage.

another suggestion, this happened to me....

the Front doors have a little plastic bung that protrudes about 5mm for the door light switch. if they are missing

you will find that the power window button lights are always on and with the key removed you can wind the windows with the doors shut.

this takes approx. 2 days to drain the battery.

Good luck

[BM WORLD 1264]

try glove box light , common for switch to move .

i had a casstte radio once that had a bent ejection arm and was activating the eject solinoid and that causing the prob .

[phil millar 0]

Hi, alternators always have a slight drain on your battery,thats why you disconnect the leads if you are not using the car for a long period.

[hotwire 352]

Hi, alternators always have a slight drain on your battery,thats why you disconnect the leads if you are not using the car for a long period.

Not correct. A "correct" fitment alternator does NOT draw current at rest (assumming no fault in it) they can do with a fault or if an incorrect unit is fitted for a specfic wiring set-up - Depending on whether a vehicle is wired for ign or battery sense.

A fault in an alternator to create draw at rest (short in a diode or stator) would usually draw more than this - about 1.5 amps or so & will quite quickly flatten a battery while at rest.

Without an alarm fitted, a vehicle will draw up to about .06 milli amps at rest -max (usually less) this being the the memory for electronics/clock/radio etc.

With an alarm this can vary but sometimes up to .25 amp (usually less) which will accelerate discharge over time.

As already said - with ammeter in line -remove each battery fuse at a time to confirm which circuit the draw is in.

Glovebox light is the only bulb likely to cause this as the rest will all draw more current.