Battery Going FLAT - Page 2

raykay · 22nd November 2020, 19:18

Quote:

Originally Posted by macafee2

is a saloon what about boot light?
macafee2

It's on the same circuit as the interior lights, if they are off, so is the boot light.

steve-45 · 22nd November 2020, 19:29

Quote:

Originally Posted by macafee2

is a saloon what about boot light?

macafee2

I’ll fold a rear seat down so I can see in the boot when the car is locked up.

Thank you all for your suggestions.

T-Cut · 22nd November 2020, 19:56

Is there an OEM SatNav or a FBH?
TC

steve-45 · 22nd November 2020, 20:12

No OEM satnav and I have unplugged the 2 plugs from the FBH

COLVERT · 23rd November 2020, 16:13

Quote:

Originally Posted by steve-45

No OEM satnav and I have unplugged the 2 plugs from the FBH

No doubt you will eventually find the problem.---When you do could you tell us curious lot what it was please ??---

steve-45 · 23rd November 2020, 18:01

I did check and the boot light does go off.

Not much progress today, seemed to be one conference call after another.

As and when I find the problem I will post up my findings - nothing I find more annoying than when people don’t post up the solution.

steve-45 · 24th November 2020, 14:27

OK, some more investigation. After reading HarryM1BYT's excellent how to on measuring battery discharge I disconnected the main battery feed into the under bonnet fuse box with the following results.

Ammeter connected between disconnected main feed and fuse box connection resulted in about 45mA which is about right as I did not wait too long.

Leaving the feed to the fuse box disconnected I then connected the ammeter between the battery -ve pole and earth. According to Harry's write up the only 2 items not connected via the fuse box are the alternator and starter motor.

I got a current reading of 400mA ( previously with every thing connected I was getting about 450mA ------- 400 + 45 = about 450mA)

I am beginning to suspect that there maybe a leakage problem with the alternator diode pack - but having large hands I can't get down there to pull the plug off the back of the alternator, and if I could I doubt very much I could get it back on again.

Does 400mA (0.4A) drain sound possible for a faulty diode pack?

I shall be releived and annoyed if it is the alternator as a reconditioned unit was only fitted 18 months ago.

COLVERT · 24th November 2020, 15:18

Yes, it is possible and the diode pack could be the culprit.---

I'm not sure but could it be possible to disconnect the cable to the alternator at the battery end ??---

steve-45 · 2nd December 2020, 15:35

OK, an update on what I found.

Not looked at problem for a couple of weeks, luckily its a second car, repeated previous tests and with the fuse box supply disconnected it was still drawing 450mA.
Pulled the squarish plug out the back of the alternator still 450mA current draw.

Disconnected the heavy bolted on wire from the back of the alternator and current draw drops to ZERO! Cleaned all the connections and re-bolted the wire into place - current draw back to 450mA.

Conclusion it must be the alternator, which I will get replaced in a week or two's time.

Thanks everybody for your help in fault finding this one.

FrattonEnder · 2nd December 2020, 15:52

Wonder if that's why my battery was going flat if the car wasn't used for around 10 days. She's been OK for the last 3 weeks now that I've been running her a couple of times a week.
Don't fancy rummaging around in the engine bay now it's getting colder so that'll be one added to my springtime check and fix list - which is getting longer!

24th November 2020, 15:18	#18
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	Yes, it is possible and the diode pack could be the culprit.--- I'm not sure but could it be possible to disconnect the cable to the alternator at the battery end ??--- Last edited by COLVERT; 24th November 2020 at 15:20..

2nd December 2020, 15:52	#20
FrattonEnder Avid contributor MG ZT Join Date: May 2020 Location: Gloucester Posts: 233 Thanks: 40 Thanked 47 Times in 28 Posts	Wonder if that's why my battery was going flat if the car wasn't used for around 10 days. She's been OK for the last 3 weeks now that I've been running her a couple of times a week. Don't fancy rummaging around in the engine bay now it's getting colder so that'll be one added to my springtime check and fix list - which is getting longer! __________________ Serial Longbridge owner - Rover 213SE, Rover 216GTi, Rover 416 SLi, MG ZS 120+, MG ZT CDTi, MG ZT-T 190. Flies in the ointment - Ford Mondeo Mk4 CDTi Zetec, MINI Cooper 1.6

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22nd November 2020, 19:56	#13
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,751 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	Is there an OEM SatNav or a FBH? TC

22nd November 2020, 20:12	#14
steve-45 This is my second home Rover 75 Saloon CDTi Join Date: Oct 2015 Location: Belvedere Posts: 4,076 Thanks: 108 Thanked 1,089 Times in 774 Posts	No OEM satnav and I have unplugged the 2 plugs from the FBH

23rd November 2020, 18:01	#16
steve-45 This is my second home Rover 75 Saloon CDTi Join Date: Oct 2015 Location: Belvedere Posts: 4,076 Thanks: 108 Thanked 1,089 Times in 774 Posts	I did check and the boot light does go off. Not much progress today, seemed to be one conference call after another. As and when I find the problem I will post up my findings - nothing I find more annoying than when people don’t post up the solution.

24th November 2020, 14:27	#17
steve-45 This is my second home Rover 75 Saloon CDTi Join Date: Oct 2015 Location: Belvedere Posts: 4,076 Thanks: 108 Thanked 1,089 Times in 774 Posts	OK, some more investigation. After reading HarryM1BYT's excellent how to on measuring battery discharge I disconnected the main battery feed into the under bonnet fuse box with the following results. Ammeter connected between disconnected main feed and fuse box connection resulted in about 45mA which is about right as I did not wait too long. Leaving the feed to the fuse box disconnected I then connected the ammeter between the battery -ve pole and earth. According to Harry's write up the only 2 items not connected via the fuse box are the alternator and starter motor. I got a current reading of 400mA ( previously with every thing connected I was getting about 450mA ------- 400 + 45 = about 450mA) I am beginning to suspect that there maybe a leakage problem with the alternator diode pack - but having large hands I can't get down there to pull the plug off the back of the alternator, and if I could I doubt very much I could get it back on again. Does 400mA (0.4A) drain sound possible for a faulty diode pack? I shall be releived and annoyed if it is the alternator as a reconditioned unit was only fitted 18 months ago.

2nd December 2020, 15:35	#19
steve-45 This is my second home Rover 75 Saloon CDTi Join Date: Oct 2015 Location: Belvedere Posts: 4,076 Thanks: 108 Thanked 1,089 Times in 774 Posts	OK, an update on what I found. Not looked at problem for a couple of weeks, luckily its a second car, repeated previous tests and with the fuse box supply disconnected it was still drawing 450mA. Pulled the squarish plug out the back of the alternator still 450mA current draw. Disconnected the heavy bolted on wire from the back of the alternator and current draw drops to ZERO! Cleaned all the connections and re-bolted the wire into place - current draw back to 450mA. Conclusion it must be the alternator, which I will get replaced in a week or two's time. Thanks everybody for your help in fault finding this one.