Battery drain - Page 2

marinabrian · 15th December 2017, 07:07

One of the most common causes of current drain on R40 models is a defective LSM

The led backlighting for the light switch controls remains illuminated, which in turn does not allow the BCU to enter it's "sleep mode" where a quiescent current of 45 mA is to be expected, instead you will experience a current draw of between 2.5 and 3 amps.

The test for this is simple, look throught the window of a locked car after dark, if the light switch is lit, then the LSM must be replaced

Brian

mikeh · 15th December 2017, 11:00

Does the R40 only go into 'sleep mode' when locked? I always leave my car unlocked in the garage as I assumed without the alarm on there would be less battery drain.

Mike Noc · 16th December 2017, 08:14

No, you don't have to lock it for the ECU's to go into sleep mode - just turn the ignition off.

pugcrew · 16th December 2017, 19:22

Quote:

Originally Posted by marinabrian

One of the most common causes of current drain on R40 models is a defective LSM

The led backlighting for the light switch controls remains illuminated, which in turn does not allow the BCU to enter it's "sleep mode" where a quiescent current of 45 mA is to be expected, instead you will experience a current draw of between 2.5 and 3 amps.

The test for this is simple, look throught the window of a locked car after dark, if the light switch is lit, then the LSM must be replaced

Brian

Thanks for this suggestion. Tonight was the first opportunity I have had to look at the light switch in the dark. It was not illuminated so it doesn't appear to be the LSM.

I'm still open to suggestions!!

Synchromesh · 18th January 2018, 12:04

Hi Pugcrew,

Did you manage to resolve your current drain problem?

Regards,

Synchromesh.

pugcrew · 20th January 2018, 19:13

Quote:

Originally Posted by Synchromesh

Hi Pugcrew,

Did you manage to resolve your current drain problem?

Regards,

Synchromesh.

I think that it is down to the SatNav not shutting off. I've monitor the current flow with and without this connected and there is a difference. This was not easy as I found that it could take anything up to 20 minutes before everything shut down and any disturbance meant that that is took another 20 minutes to get into a fully sleep mode.

I'm still not convinced that it is only the SatNav but I have left it disconnected for about 10 days now and haven't had any flat battery problems.

Synchromesh · 29th January 2018, 11:35

Thank you for the feedback.

YHT · 11th March 2018, 09:55

Not sure that this is where my reply should be but here goes. Have a 51 reg diesel 75 with a battery drain. Have disconnected the alternator and fbh and the glow plug fuse link to no avail. It drains at 0.09A with fuse 5 in and 0.05A with fuse F5 in. When replacing F5 (with the door open) the ammeter rises to 2.05A (internal light on) for 20 seconds, and then drops to 1.75A with the internal light still on. Turn off the internal light and it drops to 0.39A for a while and then drops back to 0.09A after 3 mins or so. I have tried to reconnect the fbh and the current rises to 0.13A and then drops back to 0.09A. I understand form the threads that the drain should be 0.05A so believe something somewhere is "leaking"! Thoughts please? (There is no sat nav and the aftermarket CD player don't seem to be the problem). Normal daily use shouldn't be a problem but leaving it at an airport for a week means coming back to a flat battery which has been renewed in the recent past.

marinabrian · 11th March 2018, 10:04

Quote:

Originally Posted by YHT

Not sure that this is where my reply should be but here goes. Have a 51 reg diesel 75 with a battery drain. Have disconnected the alternator and fbh and the glow plug fuse link to no avail. It drains at 0.09A with fuse 5 in and 0.05A with fuse F5 in. When replacing F5 (with the door open) the ammeter rises to 2.05A (internal light on) for 20 seconds, and then drops to 1.75A with the internal light still on. Turn off the internal light and it drops to 0.39A for a while and then drops back to 0.09A after 3 mins or so. I have tried to reconnect the fbh and the current rises to 0.13A and then drops back to 0.09A. I understand form the threads that the drain should be 0.05A so believe something somewhere is "leaking"! Thoughts please? (There is no sat nav and the aftermarket CD player don't seem to be the problem). Normal daily use shouldn't be a problem but leaving it at an airport for a week means coming back to a flat battery which has been renewed in the recent past.

Check your background illumination on the light switch fascia isn't remaining on with the car locked

Brian

YHT · 12th March 2018, 10:57

Thanks for the suggestion Brian. Have tried what you suggested (after having adjusted the brightness to full) but still 0.09A after it settled down. Looking at earlier threads I have checked the plenum, chamber and its dry (the car has been in a barn this past couple of weeks and a garage before that so no moisture).

11th March 2018, 09:55	#18
YHT Loves to post Rover 75 Saloon Join Date: Jun 2017 Location: suffolk Posts: 261 Thanks: 46 Thanked 25 Times in 23 Posts	battery drain Not sure that this is where my reply should be but here goes. Have a 51 reg diesel 75 with a battery drain. Have disconnected the alternator and fbh and the glow plug fuse link to no avail. It drains at 0.09A with fuse 5 in and 0.05A with fuse F5 in. When replacing F5 (with the door open) the ammeter rises to 2.05A (internal light on) for 20 seconds, and then drops to 1.75A with the internal light still on. Turn off the internal light and it drops to 0.39A for a while and then drops back to 0.09A after 3 mins or so. I have tried to reconnect the fbh and the current rises to 0.13A and then drops back to 0.09A. I understand form the threads that the drain should be 0.05A so believe something somewhere is "leaking"! Thoughts please? (There is no sat nav and the aftermarket CD player don't seem to be the problem). Normal daily use shouldn't be a problem but leaving it at an airport for a week means coming back to a flat battery which has been renewed in the recent past.

12th March 2018, 10:57	#20
YHT Loves to post Rover 75 Saloon Join Date: Jun 2017 Location: suffolk Posts: 261 Thanks: 46 Thanked 25 Times in 23 Posts	Battery drain Thanks for the suggestion Brian. Have tried what you suggested (after having adjusted the brightness to full) but still 0.09A after it settled down. Looking at earlier threads I have checked the plenum, chamber and its dry (the car has been in a barn this past couple of weeks and a garage before that so no moisture).

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

15th December 2017, 07:07	#11
marinabrian MG ZT Join Date: Jan 2011 Location: Newcastle Upon Tyne Posts: 20,151 Thanks: 3,565 Thanked 10,837 Times in 5,718 Posts	One of the most common causes of current drain on R40 models is a defective LSM The led backlighting for the light switch controls remains illuminated, which in turn does not allow the BCU to enter it's "sleep mode" where a quiescent current of 45 mA is to be expected, instead you will experience a current draw of between 2.5 and 3 amps. The test for this is simple, look throught the window of a locked car after dark, if the light switch is lit, then the LSM must be replaced Brian

15th December 2017, 11:00	#12
mikeh Regular poster Rover 75 Saloon Join Date: Nov 2006 Location: South Croydon Posts: 71 Thanks: 25 Thanked 2 Times in 2 Posts	Does the R40 only go into 'sleep mode' when locked? I always leave my car unlocked in the garage as I assumed without the alarm on there would be less battery drain.

16th December 2017, 08:14	#13
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,547 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	No, you don't have to lock it for the ECU's to go into sleep mode - just turn the ignition off.

18th January 2018, 12:04	#15
Synchromesh Gets stuck in Rover 75 Saloon Join Date: Jan 2010 Location: Preston Posts: 624 Thanks: 50 Thanked 44 Times in 32 Posts	Hi Pugcrew, Did you manage to resolve your current drain problem? Regards, Synchromesh.

29th January 2018, 11:35	#17
Synchromesh Gets stuck in Rover 75 Saloon Join Date: Jan 2010 Location: Preston Posts: 624 Thanks: 50 Thanked 44 Times in 32 Posts	Thank you for the feedback.