Battery Drain Readings

[PG325]

For the last couple of years I've always suffered with a battery drainage problem, the car doesn't get used that much throughout summer and not at all in Winter, its not usually an issue as I use a CTEK trickle charger when not using the car.

I did the amp drainage test today, multimeter in series between the negative battery terminal and earth lead. With nothing switched on and doors closed I got this reading, I had the meter on the 10A setting so I think this is reading 200ma. Removing fuse 28 dropped the reading to 00.9 which I believe is 90ma. Running off fuse 28 is the stereo, removing the stereo again dropped in to 0.09, so I'm assuming this is all that's running through fuse 28 whilst the ignition is off.

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I know 200ma or 90ma is excessive (assuming I'm reading the meter correctly), but I also checked my daily drive Astra and found that the reading with nothing on and all doors closed was also 02.0

Can someone confirm the readings are actually 200ma and 90ma, plus I'm now thinking it could be a dud battery an the Astra is taking the same current but doesn't go flat.

[Brianmoooore]

That's 2000mA not 200mA, so it's not surprising your battery's going flat! 00.9 is 900mA, so still about 20 X what the everything off drain should be.
Is there an auxiliary amplifier running from the stereo? That's more likely to be faulty than the stereo itself.

[PG325]

That's 2000mA not 200mA, so it's not surprising your battery's going flat! 00.9 is 900mA, so still about 20 X what the everything off drain should be.
Is there an auxiliary amplifier running from the stereo? That's more likely to be faulty than the stereo itself.

The stereo does have a small amp but I disconnected it then reconnected the stereo, it made no difference to the reading, still read 02.0

I've pulled every fuse and relay and nothing made a big difference, in fact by pulling fuse 27 the reading to 01.8 and pulling fuse 21 only dropped it to 01.9.

It's odd that the Astra gave a similar reading but the battery is fine.

Out of interest I removed the black fusebox wire from the battery and it dropped to 0.01, is there anything that could pull power through the battery to fusebox cable but not have a fuse?

[Brianmoooore]

Black fusebox cable? The only black wire is the big thick one to the starter motor, and then on to the alternator. The wires to the engine loom, fusebox, and ABS pump are all red.
A duff alternator diode will give a drain of the order of a couple of amps.

[PG325]

Black fusebox cable? The only black wire is the big thick one to the starter motor, and then on to the alternator. The wires to the engine loom, fusebox, and ABS pump are all red.
A duff alternator diode will give a drain of the order of a couple of amps.

This is how the positive terminal looks, forget the 2 reds on the right of the picture, they are the amp and CTEK charger port, neither are draining. There is the three red wires at the top of the pic and two larger black cables on the left, both black cables appear to go into the fuse box base, if these black cables are removed, thats when the reading drops to 0.01

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[DanThe]

The 2 black cables are actually red, they just have black insulation covering them, one is power to the fusebox (why the reading drops to naff all when disconnected) and the other is for the ABS

[Speedtouch]

A reading of 2.0 on the 10A range indicates a drain of 2 Amps - quite alot!

[PG325]

A reading of 2.0 on the 10A range indicates a drain of 2 Amps - quite alot!

I know, it drops by 1.1 amp when the stereo is disconnected but that still leaves 0.9 amps feeding other things. 0.3 amps to fuses 21 and 27 combined but still 0.6 amps that doesn't reduce when removing any fuses. There is an alarm which I believe was connected into the existing alarm loom, the LED remains powered so I assume this is taking some of the drain.

Although 1.1 amps for stereo which isn't switched on is high.

Any ideas anyone.

[Speedtouch]

An LED will only consume around 20mA at most. Have you checked to ensure the boot light isn't staying on - a common cause of mysterious battery drain.

[PG325]

An LED will only consume around 20mA at most. Have you checked to ensure the boot light isn't staying on - a common cause of mysterious battery drain.

That would have highlighted itself by removing the fuses, but no the light isn't staying on.

[Quaser]

I had this issue - but after loads of trouble shooting and unable to find the source, it disappeared when I changed my electric ariel

[Speedtouch]

A sticking electric aerial relay would indeed cause this sort of issue, as it would be constantly powering the motor, which probably draws about 2A.

[Brianmoooore]

Electric aerial should be wired through fuse 28, but after the efforts of the average ICE installer, who knows.
A drain of 2A will be producing about 25W of heat, which is the same as my general purpose soldering iron, so there should be some significant warming somewhere.

[ranxerox]

delete

[broadie]

Try pulling some relays Im sure they won't all be fused (but I don't have a diagram)

[ranxerox]

delete

[PG325]

Electric aerial should be wired through fuse 28, but after the efforts of the average ICE installer, who knows.
A drain of 2A will be producing about 25W of heat, which is the same as my general purpose soldering iron, so there should be some significant warming somewhere.

I've unplugged the red aerial cable which plugs into the accessory panel and no difference to the reading. There is another white cable which goes to the power on supply from the rear of the stereo. As mentioned before unplugging the stereo reduces it from 02.0 to 00.9, assuming we're reading the meter correctly that mean the stereo when switched off is drawing 1.1 amps.

Just out of interest I also unplugged the 6 button OBC and the reading dropped from 00.9 to 00.8 which I assume is 100ma, even the OBC is high when I think I should only have 50ma maximum drain.

Am I definitely reading the meter correctly?

[Speedtouch]

I'm wondering if your multimeter is giving incorrect readings; I have a very similar model of DMM (with the same '830' in the model number), and on the 10A range, mine displays "0.00", i.e., if you were to feed 2A into it, it would display "2.00".

Yours seems to have the decimal point in the wrong place!

So, theoretically, yours is actually reading 200mA, or 0.2A.

[PG325]

I'm wondering if your multimeter is giving incorrect readings; I have a very similar model of DMM (with the same '830' in the model number), and on the 10A range, mine displays "0.00", i.e., if you were to feed 2A into it, it would display "2.00".

Yours seems to have the decimal point in the wrong place!

So, theoretically, yours is actually reading 200mA, or 0.2A.

This could be right, as a test I just switched the headlights on and the reading jumped from 02.0 to 135.20, if we follow the same logic that's 135 amps, whereas the front and rear lights, plus licence plate and dash lights would probably draw something like 13 amps, I did a simple watts divided by volt calculation

Also I think a drain of 2 amps would flatten a 70AH battery in 35 hours, mine lasts for at least a week and that with the alarm set.

Do you think the lights on test has demonstrated that it really is 200mA?

[Speedtouch]

Yes, I would think so; 135A would be a ridiculous drain to power the lights!

The way to confirm this would be to get it back to the reading of "02.0" on the 10A range, then switch over to the 200mA range, whereupon you should get a full scale deflection reading, i.e., 199.9 or thereabouts.

Don't forget, you'll need to move the + red lead to the V/mA socket to do this.