Excessive current draw?

[Norbie]

I've been having problems with the battery in the Century going flat after a week or so. It's a giant truck battery and only about a year old so it shouldn't be dead already.

Anyway I just checked the current draw with everything supposedly switched off, and according to my multimeter it's a bit under 2 amps. Sounds a bit high to me - or is this normal?

[wilbo666]

Sounds too high.

Pull all the fuses and put them in one by one to see if you can narrow down the circuit pulling the current would be my suggestion

Cheers
Wilbo

[willwal98]

Do you have any amps in it?

[oldcorollas]

no info in engine or wiring book as to static draw, but 2amps is stupid high.

pull fuses one by one and note drop in current until you find the culprit.
perhaps disconnect alt first, see if it is leaky diodes

[oldcorollas]

relevant?
http://www.toymods.org.au/forums/sho...66#post1212766

[JZA70 R]

may be a silly question, but how do you actually measure current draw?

is it by simply switching your MM to amps and putting it inline between your positive or negative battery pole and its respective terminal?

[roadsailing]

may be a silly question, but how do you actually measure current draw?

is it by simply switching your MM to amps and putting it inline between your positive or negative battery pole and its respective terminal?

yep. just don't try to start it hooked up like that

[willwal98]

yep. just don't try to start it hooked up like that

Or you can use a clamp meter without disconnecting anything, good for seeing how much current something draws when it going.

Clamp Meter Example

[big_zop]

Not quite roadsailing.

Apart from using something similar to what willwal has posted, to measure current you will need to break the circuit and put the multimeter in series (in-line) so it becomes part of the circuit - ala click. So the easiest way would be to remove the fuse and measure it from there, PROVIDED you know there isn't a known issue with the fuse blowing.

To measure voltage, you are connecting up the multimeter in parallel so the original circuit remains unbroken - ala click

[roadsailing]

Not quite roadsailing.

Apart from using something similar to what willwal has posted, to measure current you will need to break the circuit and put the multimeter in series (in-line) so it becomes part of the circuit - ala click. So the easiest way would be to remove the fuse and measure it from there, PROVIDED you know there isn't a known issue with the fuse blowing.

Yes quite big_zop, there are unfused connections to the positive terminal and it will work if you put the meter between the positive terminal and the positive clamp (or negative) i'd suggest using a cheap meter for it, and most of them go up to 10 amps (from memory), and if you have a 10 amp current draw your battery will be going flat stupidly fast.

that way you will be checking every single wire, and not just the ones that are fused, for example a 6 ohm resistor might have somehow stabbed into the started motor cable and touched ground.

anyway i got as far as peasuring what the current drain was on my car, but never found out what the cause was, I just unhooked the negative terminal every night and put it back on in the morning while i was putting half a litre of water into the radiator.

[big_zop]

Ok, I did misread the way Todd put it as putting the two probes of the multimeter between the positive and negative terminals.

But I suspect that is how Norbie got his 2A figure but now needs to determine where the draw is coming from, and with something as complex as the Century, its going to be quite a task.

[2jzhilux]

Around 2 amps is definately way to high, you would be expecting to have around 0.05amps
Measure the current draw and pull the fuses to find the circuit at fault.
Once you have found the circuit with the current draw put your multimeter across the fuse and start disconnnecting plugs in that circuit to narrow it down further.

[MWP]

First thing to check for is any lights/globes being left on.
Glovebox, boot, etc switches fail leaving the globes turned on which you dont notice as the compartments are closed.