Thread: mystery current leakage

You need a multi meter. Start pulling fuses and find were the power is being drawn.
I cant imagine this sort of power is being drawn and you are not blowing fuses, is battery ok?
What voltage have you got connected?...........disconnected?

An auto electrician will find it pretty quickly this way.

If you disconnect the battery and it still drops voltage then your battery is stuffed. A load big enough to drag a healthy battery down that fast would create heat and smoke, in short order.

Originally Posted by RR P38

You need a multi meter. Start pulling fuses and find were the power is being drawn.
I cant imagine this sort of power is being drawn and you are not blowing fuses, is battery ok?
What voltage have you got connected?...........disconnected?

An auto electrician will find it pretty quickly this way.

I've been using a multimeter. I have checked across the fuses for voltage in parallel. None indicated any voltage and no fuses blown. RACQ came out for a look but couldn't pick the problem. He used a current clamp meter which showed it was losing 4 amps.

When I found the battery dead I tried charging it and it wouldn't accept charge. I assumed it was dead and removed it. Tonight I put it back on the charger (on the work bench) and it is accepting charge. Another mystery. I will see what its like tomorrow after a night in the charger. Currently, its holding about 12.2 volts.

I have another battery and have been using that. I only connect it when I am trying to work out the problem, and then top it up with a charger. Otherwise its disconnected to avoid killing that battery.

Originally Posted by bee utey

If you disconnect the battery and it still drops voltage then your battery is stuffed. A load big enough to drag a healthy battery down that fast would create heat and smoke, in short order.

Its only dropping voltage when connected.

There is no heat or smoke.

Well, at 4 amps there wouldn't be any smoke! You could have killed the original battery though. Totally dead flattened batteries usually don't come good.

Anyway, I'd fit your multimeter set on 10 amps between the positive terminal and the battery cable, as well as a 15A fuse to protect the meter, then disconnect things one at a time, starting with the alternator output cable, the starter motor, radio, headlamp switch etc. Basically any accessory that is unfused as you've checked the fuses already.

Originally Posted by bee utey

Well, at 4 amps there wouldn't be any smoke! You could have killed the original battery though. Totally dead flattened batteries usually don't come good.

Anyway, I'd fit your multimeter set on 10 amps between the positive terminal and the battery cable, as well as a 15A fuse to protect the meter, then disconnect things one at a time, starting with the alternator output cable, the starter motor, radio, headlamp switch etc. Basically any accessory that is unfused as you've checked the fuses already.

Good idea, thanks. I don't hold much hope for the original battery.

well I think I am going crazy. The voltage drop has stopped. I hooked up the multimeter to measure amps and its showing a drain of 0.01 amps. Which is nothing.

The second hand battery is only showing 12.15 volts after being on charge all night. It didn't have enough charge to start the motor (clicking sound). So its probably dead.

The original calcium battery (thought to be dead) is holding 13 volts after being on the charger all night. So it might have some life in it. I don't know why it wasn't charging before.

I tried to jump start the second hand battery using the calcium battery. The starter turned slowly but not enough to kick it to life. I know my jumper leads are pretty useless (more insulation that wire on the cables) but I thought it would be enough to start the motor.

So tomorrow I will try fitting the calcium battery see if it will start.

i've had a similar problem before - there was a relay that was not fused, or through the ignition switch that was always on when the battery was on and it pulled about 200mA - enough to flatten the battery. This was compounded by an insufficiently sized alternator that could not keep up when driving at night with either the spots on, or the AC on. These two things were the actual problems..

But the symptom was the battery seemed like it wouldn't charge, and if it was already down it would be flat quite quickly... which did actually cause the battery to fail.

I guess that is a long way of saying its possible after you get the new battery you will quickly have to continue the detective work

Do you still get the drain after removing all fuses? (take a photo before so you can easily put them back). I 110 should go battery -> starter -> Alt & loom. With the fuses out disconnect the alt (and check for the drain), then the stater (check for the drain). and just work forward through the loom checking at each point. If you have a light with a needle point you will be able to trace the live wire by giving it a tiny *****.

It is tedious for sure.. 4amps should be enough to swing a compass, i've heard of people tracing faults with that too.