Battery drain

[Omega man 1969]

My CSi has always had an issue with the batteries going flat after a few weeks of standing. I decided to check out how many milliamperes were being pulled with the ignition off.

With the boot open I was seeing about 610 ma dropping to 95 ma after 16 minutes. Pulling fuse 43 dropped it to 86ma. Removing k72 and k73 made no difference, still 86ma.

Trunk lights turned off after 16 minutes. I have pulled every fuse and every relay and it still sits at 86 ma.

Any ideas ?

[taylorpatterson]

My CSi has always had an issue with the batteries going flat after a few weeks of standing. I decided to check out how many milliamperes were being pulled with the ignition off.

With the boot open I was seeing about 610 ma dropping to 95 ma after 16 minutes. Pulling fuse 43 dropped it to 86ma. Removing k72 and k73 made no difference, still 86ma.

Trunk lights turned off after 16 minutes. I have pulled every fuse and every relay and it still sits at 86 ma.

Any ideas ?

Are your throttle bodies continuing to spin after engine shut down?

http://workshop-manuals.com/bmw/8_se...)_with_ews_ii/

Need these two parts:
12514013174
61361393412

I think it was like $50 bucks for both the kit and the new relay.

This will prevent the throttle bodies from staying in a spinning state after engine shutdown, and save your batteries!

[Omega man 1969]

Thanks for thr info. No problems with the DKs, I pulled the relay and fuses for the EML ...no change still 86ma.

[Kimolaoha]

My CSi has always had an issue with the batteries going flat after a few weeks of standing. I decided to check out how many milliamperes were being pulled with the ignition off.

With the boot open I was seeing about 610 ma dropping to 95 ma after 16 minutes. Pulling fuse 43 dropped it to 86ma. Removing k72 and k73 made no difference, still 86ma.

Trunk lights turned off after 16 minutes. I have pulled every fuse and every relay and it still sits at 86 ma.

Any ideas ?

Was the stock phone removed from your car?
If so, was it properly removed, or was the cabling just cut enough to pull the phone?
If not done correctly, this could be part of your problem?

I just finished correctly disconnecting the phone electronics in the trunk - maybe it would be worth taking a peek at this thread - http://forums.bimmerforums.com/forum...ock-Cell-Phone

Also, for me, the improper disconnection of the phone had been for many years causing my ANTI-THEFT light on the radio head unit to NOT flash. Once the phone was properly disconnected, the light began flashing as it was supposed to - because the radio was no longer receiving constant power from the old phone muting circuitry.

Is your radio light flashing? If not, you may want to check your legacy phone wiring.

I've also had the "discharge in less than two weeks" issue for many years, and simply used a BandAid approach by keeping the car constantly charged with smart Deltran battery tenders. It may be that my phone issue was the problem all along - but I have not verified this as the car is a garage queen and would be on tenders anyway.

[Omega man 1969]

Interesting but there is no phone in my car or any sign there ever was. Yes my radio anti theft light blinks. I think normal load is 50ma so something is taking an extra 36ma somewhere.

[revtor]

I do recall that you already pulled some aftermarket alarm stuff from the car... Are you sure nothing is left? Like a GPS tracker for example.

[Omega man 1969]

Definitely nothing left. I do have a GPS tracker which I disconnected for the test. It pulls 5ma when connected.

I've removed the GM in the past and checked the capacitors were good, all checked out fine. I do have a problem with my windscreen wipers. If you turn the ignition off whilst they are running they don't park just stop in the middle of the screen.

[Kimolaoha]

Interesting but there is no phone in my car or any sign there ever was. Yes my radio anti theft light blinks. I think normal load is 50ma so something is taking an extra 36ma somewhere.

I thought all e31s 'back in the day' were fitted with those new-fangled phones (but may be wrong) - and there's no longer any sign in my car of a phone having ever been installed either.

Have you pulled down the trunk/boot carpeted and hinged amplifier enclosure to confirm? If there's a smaller box next to the amplifier, it's a phone module. I acknowledge that you have a non-US CSi version and that absolutely none of this may apply in your case, but maybe worth a look to rule it out?

[Omega man 1969]

Yes when I purchased the car all of that was removed and a Huge completion amplifier was fitted. I removed all of that and installed the Becker professional C RDS and Amplifier back where it should be. Luckily all the wiring was still in place. Definitely no phone system though.

[Kimolaoha]

Gotcha. Hope you track it down.
In the meantime, and in light of the fact that sulfation is irreversible, are your batteries on Deltrans?
www.batterytender.com

[Omega man 1969]

I charged them up last week, for now I have both ground connections disconnected in the trunk. Hopefully I will get to the bottom of it tomorrow. I think the next thing to do is pull all the fuses rather than one at time. I have Bluetooth multimeter that connects to my iphone, it has voice readout so I can listen as I pull the fuses.

[radlaw]

Need these two parts:
12514013174
61361393412

I think it was like $50 bucks for both the kit and the new relay.

This will prevent the throttle bodies from staying in a spinning state after engine shutdown, and save your batteries!

Does any of this apply to 840's?

[Omega man 1969]

No it's just for the v12 with electronic throttles.

[amhosib]

My CSi has always had an issue with the batteries going flat after a few weeks of standing. I decided to check out how many milliamperes were being pulled with the ignition off.

With the boot open I was seeing about 610 ma dropping to 95 ma after 16 minutes. Pulling fuse 43 dropped it to 86ma. Removing k72 and k73 made no difference, still 86ma.

Trunk lights turned off after 16 minutes. I have pulled every fuse and every relay and it still sits at 86 ma.

Any ideas ?

Every E31 that I have owned over the last 10/12 years have suffered battery drain if left over a 3/4 week period unused.(both 840and 850 cars).
I treat it as a "fact of life", and its equally valid on the larger Mercs and affects my Sl and s600.All my cars are >15 year old"future classics" as the trade likes to say, and I cant use trickle chargers for every car, so I simply use battery disconnect switches hidden somewhere on the cars.Come home after 3 months and all batteries have retained sufficient charge to start.
If I feel generous, I will use a fully charged cheapo battery as a top-up when starting.
Loosing the alarms does'nt bother me since the cars are locked and disconnect switches hidden.

- - - Updated - - -

My CSi has always had an issue with the batteries going flat after a few weeks of standing. I decided to check out how many milliamperes were being pulled with the ignition off.

With the boot open I was seeing about 610 ma dropping to 95 ma after 16 minutes. Pulling fuse 43 dropped it to 86ma. Removing k72 and k73 made no difference, still 86ma.

Trunk lights turned off after 16 minutes. I have pulled every fuse and every relay and it still sits at 86 ma.

Any ideas ?

Every E31 that I have owned over the last 10/12 years have suffered battery drain if left over a 3/4 week period unused.(both 840and 850 cars).
I treat it as a "fact of life", and its equally valid on the larger Mercs and affects my Sl and s600.All my cars are >15 year old"future classics" as the trade likes to say, and I cant use trickle chargers for every car, so I simply use battery disconnect switches hidden somewhere on the cars.Come home after 3 months and all batteries have retained sufficient charge to start.
If I feel generous, I will use a fully charged cheapo battery as a top-up when starting.
Loosing the alarms does'nt bother me since the cars are locked and disconnect switches hidden.

[Timm]

Less than 100mA is too high - but it shouldn't be discharging your batteries at any speed - it should take 1,400 hours to fully discharge the batteries. So, I would guess that the batteries have reached the end of their useful life, or, there was a measurement error.

[Omega man 1969]

Batteries are under a year old so I highly doubt there is a problem with them. I'd say 4 weeks and they are flat.

- - - Updated - - -

Both batteries are rated at 75amps so let's say 150amps and about 70% of that useable. So 105a/hr (fully charged) gives us about 43 days with 100ma drain(2.4amps/day). I would say unable to turn the engine around 30 days.

Odd thing is looking at the car right now, if I hook
up the battery with fuse 43 out I get 200ma dropping to 35ma within a minute (guessing initial surge as units power up)

I then fitted fuse 43 back in and it jumped to 500ma as expected, 16 mins later it's now at 43 ma.

Very strange

- - - Updated - - -

As I sit here watching it I see it jump to 174 ma then back to 43 as if something is switching itself on and off

[Kimolaoha]

Having just been crawling around back there in my USA version (so not sure if it's the same in your version), I know that Fuse 43 is associated with (a) the central locking system, (b) the cockpit and trunk lighting, and (c) the sunroof.
Each of these three systems also has at least one other fuse associated with it, i.e. central locking is 43 AND 42 AND 33, cockpit and trunk lighting is 43 AND 33, and Sun Roof is 43 AND 42.
You might want to sequentially pull the associated fuses and see what happens in hope of isolating the cycler.

[Omega man 1969]

Yes I think its the same setup. As far as I can tell, pulling fuse 43 seems to be like pulling the consumer relay out, which is why it drops to standby current. The same procedure yesterday was giving 85ma so I'm not sure quite what is going on. Right now its stable at 43ma which is what it should be.

I'm going to charge the batteries fully before testing again. I had a car once that had a leaky regulator pack on the alternator, that might be worth checking.

[Omega man 1969]

A bit of an update. I charged the batteries for 6 hours or so and after parking the car up I disconnected the grounds to make sure they didn't drain again. Before connecting them back up today I thought id check the voltages. One was 12.6v and the other 10.5v hmmmm looks like being completely flat for a few weeks has killed a cell. I've removed it from the car and put it on an overnight charge.

[Kimolaoha]

A bit of an update. I charged the batteries for 6 hours or so and after parking the car up I disconnected the grounds to make sure they didn't drain again. Before connecting them back up today I thought id check the voltages. One was 12.6v and the other 10.5v hmmmm looks like being completely flat for a few weeks has killed a cell. I've removed it from the car and put it on an overnight charge.

Once you get this all sorted out, you should really consider the $50 Deltran I mentioned in post 10 above. Pigtailed to one battery, it 'tends' both since they are connected in parallel, and has really kept my batteries 'as new' for years.

[Omega man 1969]

I don't have power where the car is parked. Possibly a solar solution would be an idea .

[Timm]

I don't have power where the car is parked. Possibly a solar solution would be an idea .

Fat chance in the UK! To be serious, this has been tried so many times and always with abject failure in the UK.

[Omega man 1969]

really? only needs to be 100ma to cover the drain......Even with our poor levels of sun that is possible.

- - - Updated - - -

Tim I'm not talking about those silly solar panels that plug into the cigarette lighter socket and sit on the dash. I was thinking of a 20w panel to put on the barn roof with a charge controller like this

http://www.ebay.co.uk/itm/20w-Solar-...item4ad1d66aae

[Timm]

You've got a much better chance with an external panel, stuck somewhere suitable where it faces the correct direction. My comment is more aimed at any panel that is interior to the car - they never work, not big enough, facing the wrong way and obscured by a laminate tinted window. Even one as big as the parcel shelf is not up to the job.

[Omega man 1969]

Well the battery seems to be faulty....after 24 hours of charging its still pulling 5 amps from the charger. I disconnected the charger and it sat at 12.8 volts.....2 hours later with no load connected and its at 12.1 volts.