Battery Drain

MrBIW · 24th April 2019, 20:17

I have a problem that if i can't resolve may lead to the demise of my beloved MG ztt cdti. I cannot find the cause of 2.5 amps of battery drain which is killing a full battery overnight. Having removed the sat nav unit completely ( known previous cause) i am still annoying my neighbours with alarm sounding in early hours.
I know from previous experience that with all doors closed etc the alarm usually shows 3 to 4 amps for approximately 2 minutes and then drops to 50 milliamps. Currently my car has over 4 amps for 2 minutes and then drops to 2.5Amps as the cabin lights extinguish and alarm sets.
2.5A is killing the battery.
As my car has 210k miles on it I am struggling to justify hours / cost of extensive investigation / repair.
Removing fuse 33 ( audio) makes no difference.

Sad but the end may be nigh !

trikey · 24th April 2019, 20:30

Don't give up!

Have you put a multimeter on each fuse to see if any are drawing current?

macafee2 · 24th April 2019, 20:33

I have absolutely no idea what the problem is but what about pulling a fuse at a time to see when the drain drops and go from there or have you done that?

macafee2

HarryM1BYT · 24th April 2019, 20:42

Quote:

Originally Posted by MrBIW

As my car has 210k miles on it I am struggling to justify hours / cost of extensive investigation / repair.
Removing fuse 33 ( audio) makes no difference.

Sad but the end may be nigh !

Try this way - https://the75andztclub.co.uk/forum/s...d.php?t=167111

You can begin by pulling the main fuses in the under bonnet main fuse panel, then move to pulling fuses if necessary behind the glove box.

MrBIW · 24th April 2019, 21:20

Removed Sat nav unit.( had no disc anyway !)

checked for current drain across engine bay fuse box except for the pattern of 6 square shaped fuses which I have been unable to extract. None of the Larger fuses appeared to carry the current being drained.

removed fuse 33 ( audio)

Recent faults have been the external air temp sensor which turned out to be harness break. Currently the aircon is not working, worked fine last summer but have recently tried and comressor is not kicking in but haven't had chance to investigate.

Thanks for speedy response folks

MrBIW · 24th April 2019, 21:46

Having been a lifelong Rover fan / employee ( 28 years at Longbridge) and have never owned any car not built at Longbridge or Cowley I have to say even I can't support the logic of locating the cabin fuse box up behind the glovebox!!!! as someone with two knee replacements and rapidly advancing years it is all but impossible !!! Did think if I had a sunroof I could hang by toes upside down !!

cb750chris · 24th April 2019, 22:58

Another way of checking for which circuit is responsible for the current drain is to use a multimeter and measure the (small) voltage drop across each of the fuses, and then using the tables here
https://www.powerprobe.com/fuse-voltage-drop-charts
To look up the current drawn.

Something else to check, when the car is locked, does the background lighting on the light switch go out? If not, the light switch could be doing the rest of the car going to sleep properly.
Also, check the glow plugs are not staying enabled (especially if the relay has been wet)

Good luck
Chris

Dallas · 24th April 2019, 23:02

Battery going flat that quick could be the alternator at fault which is draining the battery, use your multimeter to check the alternator output.

Also, have you done any audio mods recently such has upgrading stereo or fitting a dash cam, if so disconnect or pull the fuse and take another reading.

Blackrose · 24th April 2019, 23:19

would one of these be of any help

https://www.ebay.co.uk/itm/Automotiv...cAAOSwS~FaXd5V

My aircon wasn't working due to compressor clutch not pulling in. A re-gas fixed it. (for now anyway) Hopefully there is not a leak.

Blackrose

HarryM1BYT · 25th April 2019, 07:27

Quote:

Originally Posted by MrBIW

Removed Sat nav unit.( had no disc anyway !)

checked for current drain across engine bay fuse box except for the pattern of 6 square shaped fuses which I have been unable to extract. None of the Larger fuses appeared to carry the current being drained.

removed fuse 33 ( audio)

You cannot have it both ways, if you haven't managed to remove the large fuses, you cannot be certain which circuit is any is causing the discharge. There is also a possibility that the starter motor or alternator might be the source of the issue. 2.5amp is a substantial discharge, so should be an obvious and easy source to locate.

24th April 2019, 20:17	#1
MrBIW Newbie MG ZT-T 2.0 Diesel Join Date: Aug 2009 Location: Tamworth Posts: 18 Thanks: 9 Thanked 1 Time in 1 Post	Battery Drain I have a problem that if i can't resolve may lead to the demise of my beloved MG ztt cdti. I cannot find the cause of 2.5 amps of battery drain which is killing a full battery overnight. Having removed the sat nav unit completely ( known previous cause) i am still annoying my neighbours with alarm sounding in early hours. I know from previous experience that with all doors closed etc the alarm usually shows 3 to 4 amps for approximately 2 minutes and then drops to 50 milliamps. Currently my car has over 4 amps for 2 minutes and then drops to 2.5Amps as the cabin lights extinguish and alarm sets. 2.5A is killing the battery. As my car has 210k miles on it I am struggling to justify hours / cost of extensive investigation / repair. Removing fuse 33 ( audio) makes no difference. Sad but the end may be nigh !

24th April 2019, 20:30	#2
trikey Premium Trader Rover 75 Join Date: Nov 2010 Location: Devon Posts: 33,765 Thanks: 8,837 Thanked 14,831 Times in 8,030 Posts	Don't give up! Have you put a multimeter on each fuse to see if any are drawing current? __________________ Lest we forget..

24th April 2019, 21:20	#5
MrBIW Newbie MG ZT-T 2.0 Diesel Join Date: Aug 2009 Location: Tamworth Posts: 18 Thanks: 9 Thanked 1 Time in 1 Post	Tried so far ....... Removed Sat nav unit.( had no disc anyway !) checked for current drain across engine bay fuse box except for the pattern of 6 square shaped fuses which I have been unable to extract. None of the Larger fuses appeared to carry the current being drained. removed fuse 33 ( audio) Recent faults have been the external air temp sensor which turned out to be harness break. Currently the aircon is not working, worked fine last summer but have recently tried and comressor is not kicking in but haven't had chance to investigate. Thanks for speedy response folks

24th April 2019, 21:46	#6
MrBIW Newbie MG ZT-T 2.0 Diesel Join Date: Aug 2009 Location: Tamworth Posts: 18 Thanks: 9 Thanked 1 Time in 1 Post	Tried so far 2 ....... Having been a lifelong Rover fan / employee ( 28 years at Longbridge) and have never owned any car not built at Longbridge or Cowley I have to say even I can't support the logic of locating the cabin fuse box up behind the glovebox!!!! as someone with two knee replacements and rapidly advancing years it is all but impossible !!! Did think if I had a sunroof I could hang by toes upside down !!

24th April 2019, 22:58	#7
cb750chris Trader Rover 75 Tourer Join Date: Apr 2011 Location: Portsmouth Posts: 849 Thanks: 201 Thanked 292 Times in 200 Posts	Another way of checking for which circuit is responsible for the current drain is to use a multimeter and measure the (small) voltage drop across each of the fuses, and then using the tables here https://www.powerprobe.com/fuse-voltage-drop-charts To look up the current drawn. Something else to check, when the car is locked, does the background lighting on the light switch go out? If not, the light switch could be doing the rest of the car going to sleep properly. Also, check the glow plugs are not staying enabled (especially if the relay has been wet) Good luck Chris __________________ Now offering T4 services in the Fareham area Replacement keys programmed / supplied / cut Diesel 135 upgrade available IPK virginisation and T4 matching available Sorry, due to a big change in home circumstances, I am unable to do any large jobs at present, but can still offer evening time diagnostics. Last edited by cb750chris; 24th April 2019 at 23:00..

24th April 2019, 20:33	#3
macafee2 This is my second home Rover 75 Saloon & Tourer Join Date: Sep 2012 Location: Lincoln Posts: 14,912 Thanks: 1,630 Thanked 3,032 Times in 2,181 Posts	I have absolutely no idea what the problem is but what about pulling a fuse at a time to see when the drain drops and go from there or have you done that? macafee2

24th April 2019, 23:02	#8
Dallas This is my second home 1979 Capri 1.6L, 1982 Capri 1.6L, 2016 Dacia Stepway Join Date: Jun 2009 Location: Dorset Posts: 8,595 Thanks: 3,496 Thanked 3,397 Times in 2,218 Posts	Battery going flat that quick could be the alternator at fault which is draining the battery, use your multimeter to check the alternator output. Also, have you done any audio mods recently such has upgrading stereo or fitting a dash cam, if so disconnect or pull the fuse and take another reading.

24th April 2019, 23:19	#9
Blackrose Loves to post Rover 75 Saloon Join Date: Apr 2015 Location: Stockton - On - Tees Posts: 367 Thanks: 55 Thanked 119 Times in 88 Posts	would one of these be of any help https://www.ebay.co.uk/itm/Automotiv...cAAOSwS~FaXd5V My aircon wasn't working due to compressor clutch not pulling in. A re-gas fixed it. (for now anyway) Hopefully there is not a leak. Blackrose Last edited by Blackrose; 24th April 2019 at 23:23..