Electrical: - Battery being drained while stationary

Jungle_Jim · Jan 15th, 2014, 14:54

Hi All,
It might be because of the wet weather, and the inside of the car is humid at the moment, but it seems that the battery is draining while the car is not being used. Leaving it for more than 12 hours seems to be enough to drain the battery.

The battery has been checked OK, and the alternator is working fine because the car runs well otherwise. I notice immediately after switching the engine off today I put a multimeter across the battery and it was dropping appreciably at 0.01Volt per second, and when I took a terminal off to isolate the battery the drop was much much slower.

So - from experience of 240s is there a typical culprit for this battery drain?

And - what would be the first port of call regarding testing? How about I put a multimeter across the battery and see if the drain stops when I remove individual fuses, to find out if it's one of those circuits? Or is the drain likely to be happening from a circuit that doesn't run through the fusebox?

Thanks for reading this and any suggestions much appreciated.
John H

1992 240SE B200F Manual

Mike_Brace · Jan 15th, 2014, 15:16

Pulling the fuses out one at a time is the best route. However, do not put them back as you go. When you find the circuit that appears to be the culprit leave the fuse out and start replacing the other fuses one at a time and rechecking. By leaving out the one where there is a load and checking the others as you reinsert them you eliminate the possibility off more circuits draining as well.

Hopefully it will be just the one circuit. Then it will be a case of working out what causes the drain. A common one on saloons is the boot light left on.

jjcymru · Jan 15th, 2014, 15:20

measure current draw between live and earth on the body. get an assistant to pull fuses one at a time. if the draw drops you know which circuit is at fault and then have a better starting point.

Yaxley · Jan 15th, 2014, 21:15

Try the suggestions for localisation above, also check for any random or odd behaviour of lights etc, frayed cables to doors/tailgate/boot, any wiring near the engine that chafes as it vibrates (protected by plastic sleeves that wear eventually), and the 240 disintegrating door lock switches on the drivers door (that can energise the locks while you sleep).

Jungle_Jim · Jan 15th, 2014, 23:16

Thanks Yaxley
That could be a top tip because as it happens the driver's door central locking went kaput a few weeks ago - I assumed because it got wet during the heavy rain over Xmas.

Tomorrow I'll do the fusebox test as suggested and see which circuit is shorted, though that driver's door lock could well be the problem.

Cheers
John H

bongodave · Jan 16th, 2014, 03:12

Basics first. Ensure glovebox, bonnet and any other lights aren't sticking on.

Do checks the guys above said, then be thinking about alternator. Certain diodes and resistors go which can cause over-charging and sometimes others go which causes a drain on battery.

Before being alarmist, in the dark, turn off ignition on car, wait for courtesy light goes out and inspect carefully for any signs of glimmers of light in cab with att to glove box, radio, dash illum'.

The alternator drain is rare and most common causes are sticking switches and faulty earths.

Keep me posted pls.

Bongo.

CaptainAhab · Jan 16th, 2014, 12:28

Immobiliser / alarm fitted?

Derek UK · Jan 16th, 2014, 13:16

"when I took a terminal off to isolate the battery the drop was much much slower."

So are you saying that the battery is still discharging at a measureable level, noticeable on a meter, when it's isolated by removing one of the cables?

If so there is an internal short and the battery is kaput.

bongodave · Jan 16th, 2014, 13:18

Quote:

Originally Posted by Derek UK

"when I took a terminal off to isolate the battery the drop was much much slower."

So are you saying that the battery is still discharging at a measureable level, noticeable on a meter, when it's isolated by removing one of the cables?

If so there is an internal short and the battery is kaput.

Didn't see that bit. Cell shorted as said. New battery.

Stephen Edwin · Jan 16th, 2014, 21:15

I was wondering how the battery has been tested. Is it fully sealed or can the electrolyte water be hydrometer tested cell by cell? You might find one cell is, er, yuk.

And as a fundamental test, if you charge the battery and keep it totally disconnected, does it hold its charge?

Jan 15th, 2014, 14:54	#1
Jungle_Jim VOC Member Last Online: Jun 19th, 2024 13:06 Join Date: Sep 2009 Location: Brighton	Battery being drained while stationary Hi All, It might be because of the wet weather, and the inside of the car is humid at the moment, but it seems that the battery is draining while the car is not being used. Leaving it for more than 12 hours seems to be enough to drain the battery. The battery has been checked OK, and the alternator is working fine because the car runs well otherwise. I notice immediately after switching the engine off today I put a multimeter across the battery and it was dropping appreciably at 0.01Volt per second, and when I took a terminal off to isolate the battery the drop was much much slower. So - from experience of 240s is there a typical culprit for this battery drain? And - what would be the first port of call regarding testing? How about I put a multimeter across the battery and see if the drain stops when I remove individual fuses, to find out if it's one of those circuits? Or is the drain likely to be happening from a circuit that doesn't run through the fusebox? Thanks for reading this and any suggestions much appreciated. John H 1992 240SE B200F Manual

Jan 15th, 2014, 15:16	#2
Mike_Brace Former contributor Last Online: May 15th, 2024 09:52 Join Date: Dec 2004 Location: Rhosgoch, Anglesey	Pulling the fuses out one at a time is the best route. However, do not put them back as you go. When you find the circuit that appears to be the culprit leave the fuse out and start replacing the other fuses one at a time and rechecking. By leaving out the one where there is a load and checking the others as you reinsert them you eliminate the possibility off more circuits draining as well. Hopefully it will be just the one circuit. Then it will be a case of working out what causes the drain. A common one on saloons is the boot light left on. __________________ A Volvo is for life not just for Christmas!

Jan 16th, 2014, 03:12	#6
bongodave I've Been Banned Last Online: Feb 17th, 2014 01:36 Join Date: Dec 2013 Location: coventry	Basics first. Ensure glovebox, bonnet and any other lights aren't sticking on. Do checks the guys above said, then be thinking about alternator. Certain diodes and resistors go which can cause over-charging and sometimes others go which causes a drain on battery. Before being alarmist, in the dark, turn off ignition on car, wait for courtesy light goes out and inspect carefully for any signs of glimmers of light in cab with att to glove box, radio, dash illum'. The alternator drain is rare and most common causes are sticking switches and faulty earths. Keep me posted pls. Bongo. Last edited by bongodave; Jan 16th, 2014 at 03:23.

Jan 16th, 2014, 12:28	#7
CaptainAhab Spanner ex machina Last Online: Sep 24th, 2020 17:43 Join Date: Oct 2012 Location: Bangor	Immobiliser / alarm fitted? __________________ 1988 240DL B230K AKA: Moby

Jan 15th, 2014, 15:20	#3
jjcymru Junior Member Last Online: Oct 15th, 2018 13:54 Join Date: May 2013 Location: swansea	measure current draw between live and earth on the body. get an assistant to pull fuses one at a time. if the draw drops you know which circuit is at fault and then have a better starting point.

Jan 15th, 2014, 21:15	#4
Yaxley Member Last Online: Oct 1st, 2019 20:08 Join Date: Jun 2009 Location: London	Try the suggestions for localisation above, also check for any random or odd behaviour of lights etc, frayed cables to doors/tailgate/boot, any wiring near the engine that chafes as it vibrates (protected by plastic sleeves that wear eventually), and the 240 disintegrating door lock switches on the drivers door (that can energise the locks while you sleep).

Jan 15th, 2014, 23:16	#5
Jungle_Jim VOC Member Last Online: Jun 19th, 2024 13:06 Join Date: Sep 2009 Location: Brighton	Thanks Yaxley That could be a top tip because as it happens the driver's door central locking went kaput a few weeks ago - I assumed because it got wet during the heavy rain over Xmas. Tomorrow I'll do the fusebox test as suggested and see which circuit is shorted, though that driver's door lock could well be the problem. Cheers John H

Jan 16th, 2014, 13:16	#8
Derek UK VOC Member Last Online: Yesterday 16:45 Join Date: Jul 2006 Location: Chatham	"when I took a terminal off to isolate the battery the drop was much much slower." So are you saying that the battery is still discharging at a measureable level, noticeable on a meter, when it's isolated by removing one of the cables? If so there is an internal short and the battery is kaput.

Jan 16th, 2014, 21:15	#10
Stephen Edwin Premier Member Last Online: Oct 26th, 2023 20:42 Join Date: Jun 2010 Location: Thurrock	I was wondering how the battery has been tested. Is it fully sealed or can the electrolyte water be hydrometer tested cell by cell? You might find one cell is, er, yuk. And as a fundamental test, if you charge the battery and keep it totally disconnected, does it hold its charge?

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