Battery drain...

[Leavon 0]

I've got a parasitic drain that empties the battery over 2 or 3 days. I know it's not the battery as I replaced it a few weeks ago thinking that was the problem and I know that the alternator is charging it as I had to bump start it the other day and after 40 mins of driving it was topped up again.

I've put a multimeter across the battery and it was showing a 60 ma draw which is nothing apparently and I've checked that none of the interior lights are staying on, boot, glove box etc.

It's booked in with a sparky on monday but I wondered if anyone had any ideas for other things I might check?

Cheers,

[Alex_G60_Fanatic 0]

I've got a parasitic drain that empties the battery over 2 or 3 days. I know it's not the battery as I replaced it a few weeks ago thinking that was the problem and I know that the alternator is charging it as I had to bump start it the other day and after 40 mins of driving it was topped up again.

I've put a multimeter across the battery and it was showing a 60 ma draw which is nothing apparently and I've checked that none of the interior lights are staying on, boot, glove box etc.

It's booked in with a sparky on monday but I wondered if anyone had any ideas for other things I might check?

Cheers,

could be as simple as a faulty battery? 60ma is expected i think. where did you measure it from?

[Leavon 0]

I don't think it is as the same thing happened with the battery I had before and that wasn't very old.

 

I measured it across the battery while a mate pulled fuses, 30ma was the clock and 15 was the stereo and I reckon the rest must be the ECU?

[Alex_G60_Fanatic 0]

Time = Battery capacity / Current drawn

 

60ma on a 60amh battery is 1000hrs.... thats 41days!

[Leavon 0]

Yeah I realise that the 60 ma draw is normal and isn't the problem.

I was wondering if something could come on after the car was left for a while?

Or could an earth fault drain a battery?

[Leavon 0]

Okay I'm gonna answer my own question, I've just been out to check the car after it's been stood for an hour and I'm now getting a reading of 345ma draw on the battery.

So something is turning itself on after the car has been stood for a while, any ideas what that might be?

[Kevin Bacon 5]

Aftermarket or factory alarm? Apparently the central locking / electric windows module behind the rear door card can sap power when faulty too.

 

Does your C/L work via the door handle? I have the same issue as you, battery death within 3 days, well, not completely dead but very slow cranking. I noticed this has happened since the c/l via the door stopped working (still works via the alarm fob) and before this, I could get 7 days standby from the battery easy.

 

How are you measuring the current draw by the way? Just red and black lead of the meter across the battery terminals and set to current on the meter? Tried that on mine and display just goes "----"

 

I'm really keen to know what's causing this as the car is always a pig to Start on Monday mornings if left all weekend....

[monzablau16v 0]

i know this may sounds really stupid - but try and take a look to see that the interior light in the boot is not staying on when boot is closed?

 

I was working on my car a few weekends ago and bar from playing with the electric windows for a few minutes at a time I found that at the end of the day my battery was drained. I put it down to maybe the interior light and the bootlight being on for over 12+ hours (as i had doors and boot open).

 

sorry if this is waaay off the mark but it may be worthwhile just disconnecting then and checking the draw again to rule them out...

[Kevin Bacon 5]

/\ No that is defo a likely culprit as the microswitch in the boot latch can stick on, but in my case, i have no boot light :D

[Leavon 0]

Well it's funny you mention the central locking Kev as I just went to open the car with the key and the central locking wouldn't work, it was pushing back down as I tried to turn the key. I had to get in through the passenger door, put the key in the ignition and the C/L worked again. Maybe that's the cuprit? Anyone know how I can check it?

 

I took the positive lead off the battery and measured the current between the lead and the battery terminal, get a reading of 60ma after turning the car off and then 345ma an hour later.

 

Alarm system was deleted when it went on the fritz last year.

And yeah I checked the boot light and glove box.

[Alex_G60_Fanatic 0]

/\ No that is defo a likely culprit as the microswitch in the boot latch can stick on, but in my case, i have no boot light :D

good idea, just close the boot with the rear seats forward to check though...

 

If its not that though then im with Kev, Check the central locking. Mine kept going off and causing a flat battery. I have to disconnect the battery to stop the car from unlocking and locking itself all the time! :?

 

 

(by the way kev... Your name has changed again! :lol: )

 

Edit: whoops didn't see that post above! You know what fuse the central locking is on?

[davidwort 0]

Okay I'm gonna answer my own question, I've just been out to check the car after it's been stood for an hour and I'm now getting a reading of 345ma draw on the battery.

So something is turning itself on after the car has been stood for a while, any ideas what that might be?

 

with the meter connected, start pulling fuses, should be able to narrow down the circuit pretty quickly, have you got extra aftermarket connections direct to the battery?

 

I forgot to disconnect my meter (in-line in current mode) and operated the central locking, took a couple of goes before I popped the internal fuse in the multimeter :lol: amazed it coped that well!

[Leavon 0]

I didn't realise there were 2 other fuses for the C/L and electric windows above the main bank of fuses, going to go and check them now, the car has locked me in a couple of times so this could be the problem. Finger crossed....

[leeeeshad 0]

How are you measuring the current draw by the way? Just red and black lead of the meter across the battery terminals and set to current on the meter? Tried that on mine and display just goes "----"

 

You need to use it in series rather than parallel

 

http://www.doctronics.co.uk/meter.htm

 

The way your using it (parrallel) is for voltage and resistance.

[big ben 10]

definately sound like alarm system to me, have seen this problem many times

[Kevin Bacon 5]

Defo sounds like the C/L interface then as I seem to remember it keeps power to the windows / door locks etc for an hour after shut down, or some such!

 

Sounds like we have the same problem then. As a test, pull off the driver's side rear door card and disconnect the box of tricks you see bolted to the panel and if the draw is still only 60ma after an hour, there's your problem!

[Kevin Bacon 5]

How are you measuring the current draw by the way? Just red and black lead of the meter across the battery terminals and set to current on the meter? Tried that on mine and display just goes "----"

 

You need to use it in series rather than parallel

 

http://www.doctronics.co.uk/meter.htm

 

The way your using it (parrallel) is for voltage and resistance.

 

That'll be why then, cheers! Electricity is not my strong point :lol:

[Leavon 0]

There isn't an alarm, it was removed last year.

[leeeeshad 0]

How are you measuring the current draw by the way? Just red and black lead of the meter across the battery terminals and set to current on the meter? Tried that on mine and display just goes "----"

 

You need to use it in series rather than parallel

 

http://www.doctronics.co.uk/meter.htm

 

The way your using it (parrallel) is for voltage and resistance.

 

That'll be why then, cheers! Electricity is not my strong point :lol:

 

Just dont try and start it like that, unless you want a melted meter :epicfail:

[Leavon 0]

Cheers Kev, I'll give that a go.

[Leavon 0]

Okay I disconnected the unit behind the rear seat panel on the drivers side and no change, is that the Electric window module or the central locking?

[Kevin Bacon 5]

You still have the 345ma drain with that box disconnected?

 

I'm not sure if that's the window or c/l box, or both. I hear relay pings from it when using the windows and also after a few minutes after closing the door, so I assumed it did both.

 

Maybe time to start pulling fuses one by one as David suggested? :?

 

As an aside, my mate had the same problem with his MK4 GTI. On his car it turned out to be a dodgy diode pack in his alternator allowing it to drain current.

[Leavon 0]

Fuse pulling was the first thing I tried :(

I just tried disconnecting the C/L at the pump end and still no joy.

Alternator diode was something I had heard of, but I guess that'll be something for the sparky to investigate on monday.

 

I'll be so glad when this gets sorted, it's a bit of nightmare not knowing if the car's gonna start.

[davidwort 0]

If the alternator is causing a problem, then you might find it's slightly warm when you come to it in the morning with the engine stone cold, that would suggest a current drain through it.

Disconnect it and see if the drain still exists too.

[Leavon 0]

Thanks David I'll give that try.