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Parasitic drain
Posted: Tue Aug 24, 2021 6:39 pm
by e30-wheels
Parasitic Drain 325 e30
Over the last couple of years my battery when connected goes flat after about two week of not starting the car, finally got round to try and find the problem.
I'm getting a drain of 90.20mA done all the fuse meter checks and isolating of various components to no avail except for fues 21, although i was not having a problem with the instrument cluster i disconnected the blue plug and the 90ma drain reduced to 2.2mA.(Central locking) checked the batteries which were low and had them replaced, reconnected the cluster now i'm getting a drain of 70.2mA removing the fuse for central locking lowers the drain to 68mA, if im correct im looking for 35 to 40 mA dont know what else to check help badly needed
Many thanks in advance
Re: Parasitic drain
Posted: Tue Aug 24, 2021 9:59 pm
by Contours
Maybe you have an accessory or something connected directly to the battery and not going through the fusebox.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 7:55 am
by paultv
Do you have an alarm system? Or even the remains of one? You don't say if you've got an audio system...
It's not enough current for a bulb, except electric window switch lamps which pull 60mA each.
Paul
Re: Parasitic drain
Posted: Wed Aug 25, 2021 9:47 am
by e30-wheels
Contours wrote: ↑Tue Aug 24, 2021 9:59 pm
Maybe you have an accessory or something connected directly to the battery and not going through the fusebox.
I have no accessorys on the car only what it was built with like the radio which i disconnected along with the antenna, it all seems to be leading back to the instrument cluster and that along with the service indicator works fine. Thanks for your input
Re: Parasitic drain
Posted: Wed Aug 25, 2021 10:58 am
by e30-wheels
paultv wrote: ↑Wed Aug 25, 2021 7:55 am
Do you have an alarm system? Or even the remains of one? You don't say if you've got an audio system...
It's not enough current for a bulb, except electric window switch lamps which pull 60mA each.
Paul
Hello Paul
I don't have an alarm system or any related wiring, the audio system is the original Becker Mexico fitted by BMW when i got the car new, this was disconnected when doing tests, all the bulbs in the window switches are U/S I have now go new bulbs another job as and when, all seems to go back to the cluster SI board, i will swap this as i have a spare with good batteries. Many thanks
Re: Parasitic drain
Posted: Wed Aug 25, 2021 11:45 am
by biffer
I had a 60ma drain ,which i tracked down to the instrument blue connector/SI board- removing the board ( which had already had the batteries replaced) reduced the drain to a more normal 25ma.
Taking a chance on a second-hand board from Ebay cured it.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 12:17 pm
by Blanca
Sorry, batteries in the instrument cluster? I have had mine apart (to repair speedo gears) and a bulb problem but didn't see any batteries!
1987 E30 320i saloon
My battery last about 10 days to a fortnight unused and I mean dead flat, takes two days on a 0 .5A charger to recharge, lucky I keep a starter booster in the boot.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 1:50 pm
by paultv
Sounds like your glove box light is not switching off!
Paul
Re: Parasitic drain
Posted: Wed Aug 25, 2021 1:56 pm
by paultv
Fuse 21 feeds:
Boot/trunk light
Radio
Chime module
Instrument cluster
Active Check control
Dome light
Self Charging Flashlight in Glove box
Paul
Re: Parasitic drain
Posted: Wed Aug 25, 2021 2:23 pm
by e30-wheels
Blanca wrote: ↑Wed Aug 25, 2021 12:17 pm
Sorry, batteries in the instrument cluster? I have had mine apart (to repair speedo gears) and a bulb problem but didn't see any batteries!
1987 E30 320i saloon
My battery last about 10 days to a fortnight unused and I mean dead flat, takes two days on a 0 .5A charger to recharge, lucky I keep a starter booster in the boot.
Did you remove the SI board from the cluster housing you need to to see the batteries. also if you have not aready done it do a parasitic drain test on the car battery.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 2:28 pm
by e30-wheels
paultv wrote: ↑Wed Aug 25, 2021 1:50 pm
Sounds like your glove box light is not switching off!
Paul
Hello Paul
For testing a disconnected the glove box light,boot light
Re: Parasitic drain
Posted: Wed Aug 25, 2021 3:03 pm
by e30-wheels
paultv wrote: ↑Wed Aug 25, 2021 1:56 pm
Fuse 21 feeds:
Boot/trunk light
Radio
Chime module
Instrument cluster
Active Check control
Dome light
Self Charging Flashlight in Glove box
Paul
Hello Paul
All the above as listed have been isolated for testing except the chime module ( dont have one) test 2.2 mA, reconnected test 70.2 mA isolate cluster test 2.2mA unless there is something else on that circuit that i dont know about im thinking it must be a fault in the cluster even though it works perfectly.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 5:39 pm
by paultv
I'm going to measure mine.... all off current drain that is !!!
Paul
Re: Parasitic drain
Posted: Wed Aug 25, 2021 7:27 pm
by e30-wheels
paultv wrote: ↑Wed Aug 25, 2021 5:39 pm
I'm going to measure mine.... all off current drain that is !!!
Paul
Yes thats it, when i did mine i took all the fuses out first then did a test and got zero mA then put the fuses back one at a time but left fuse 21 out testing as i went noting the reading of any fuse that showed any mA,
Re: Parasitic drain
Posted: Wed Aug 25, 2021 7:47 pm
by onthames
Sounds like your si board batteries are on the way out.
Re: Parasitic drain
Posted: Wed Aug 25, 2021 8:23 pm
by e30-wheels
onthames wrote: ↑Wed Aug 25, 2021 7:47 pm
Sounds like your si board batteries are on the way out.
New batteries fitted Monday this week, i think it may be another fault on the si board
Thanks anyway
Re: Parasitic drain
Posted: Wed Aug 25, 2021 11:07 pm
by fixedwheelnut
It sounds like it may be your cluster as you say you have replaced the SI Board batteries, hopefully with like for like Ni-Cads
Another drain can be the door switches faulty, the front ones switch courtesy lights but also earth out the relief relay that allows you to power up the electric windows with the front doors open. Mine had a sporadic drain and I noticed the electric window switches illuminated sometimes with all the doors shut. Two new door switches fixed it
Re: Parasitic drain
Posted: Thu Aug 26, 2021 7:55 am
by e30-wheels
fixedwheelnut wrote: ↑Wed Aug 25, 2021 11:07 pm
It sounds like it may be your cluster as you say you have replaced the SI Board batteries, hopefully with like for like Ni-Cads
Another drain can be the door switches faulty, the front ones switch courtesy lights but also earth out the relief relay that allows you to power up the electric windows with the front doors open. Mine had a sporadic drain and I noticed the electric window switches illuminated sometimes with all the doors shut. Two new door switches fixed it
The old si board batteries were replaced as near as possibile like for like same rating but slightly fatter by a local electronics repair company i assume they were original as dated 1989 one was u/s the other 2.6 volts, before new batteries battery drain was over 90mA after 70.2mA both before and now the cluster works perfectly, the window switch light bulbs are all u/s and have been removed pending the fitting of new bulbs, you mention a relief relay i can' find a relay on my window circuit only a circuit breaker and number 17 fuse which was removed when testing do you know its location. I have another si board with good batteries which i will fit today, fingers crossed.
Many thanks for your reply
Re: Parasitic drain
Posted: Sat Aug 28, 2021 1:53 pm
by e30-wheels
Problem solved, I fitted my spare si board but the rev counter and fuel econ gauges did not function then realised i had left 21 fuse and a relay out refitted them and all was ok with all systems now working perfectly, checkd the parasitic drain now reading 7.2mA, so the problem ended up being a fault somewhere on the old si board.
Hopefully no more flat btatteries.
Thanks to all for the help and suggestions.
Re: Parasitic drain
Posted: Sat Aug 28, 2021 2:02 pm
by martauto
e30-wheels wrote: ↑Sat Aug 28, 2021 1:53 pm
Problem solved, I fitted my spare si board but the rev counter and fuel econ gauges did not function then realised i had left 21 fuse and a relay out refitted them and all was ok with all systems now working perfectly, checkd the parasitic drain now reading 7.2mA, so the problem ended up being a fault somewhere on the old si board.
Hopefully no more flat btatteries.
Thanks to all for the help and suggestions.
Great news mate !!!!
I would not have thought about this in a million years
Mart.
Re: Parasitic drain
Posted: Sat Aug 28, 2021 6:02 pm
by e30-wheels
martauto wrote: ↑Sat Aug 28, 2021 2:02 pm
e30-wheels wrote: ↑Sat Aug 28, 2021 1:53 pm
Problem solved, I fitted my spare si board but the rev counter and fuel econ gauges did not function then realised i had left 21 fuse and a relay out refitted them and all was ok with all systems now working perfectly, checkd the parasitic drain now reading 7.2mA, so the problem ended up being a fault somewhere on the old si board.
Hopefully no more flat btatteries.
Thanks to all for the help and suggestions.
Great news mate !!!!
I would not have thought about this in a million years
Mart.
Thanks Fixedwheelnut was a great help.
Re: Parasitic drain
Posted: Mon Aug 30, 2021 4:15 pm
by Blanca
Being a bit paranoid I checked my batteries and the CR14250 SE 3v Lithium batteries are 2.6v after sitting with no main battery in the car for over a month. Everything on the cluster works just fine but I am getting battery drain, about ten days and it's flat but driven every few days it is fine and starts first turn.
Would this be OK as I don't really want to mess about changing perfectly good batteries.
Re: Parasitic drain
Posted: Mon Aug 30, 2021 6:44 pm
by e30-wheels
Blanca wrote: ↑Mon Aug 30, 2021 4:15 pm
Being a bit paranoid I checked my batteries and the CR14250 SE 3v Lithium batteries are 2.6v after sitting with no main battery in the car for over a month. Everything on the cluster works just fine but I am getting battery drain, about ten days and it's flat but driven every few days it is fine and starts first turn.
Would this be OK as I don't really want to mess about changing perfectly good batteries.
When my batteries were replaced one was zero volts the other was 2.6v apparently 2.6 volts is flat, like you my instruments all worked ok although i had to reset the service lights each time the main car battery was low, apparently bad si board batteries can cause a high parasitic drain on the system , I would certainly replace the si batteries, when new the batteries are about 3.3 volt. pull the blue plug off the cluster and see what readings you get.
Re: Parasitic drain
Posted: Wed Sep 01, 2021 2:22 pm
by Blanca
Two new batteries on the way,
https://www.ebay.es/itm/283281016145
Put it all back for now as with the wheel off it is not too bad a job, (unless you drop the thumb nut off the dash cover down the inside of the consul
)
Re: Parasitic drain
Posted: Wed Sep 01, 2021 4:11 pm
by onthames
e30-wheels wrote: ↑Mon Aug 30, 2021 6:44 pm
Blanca wrote: ↑Mon Aug 30, 2021 4:15 pm
Being a bit paranoid I checked my batteries and the CR14250 SE 3v Lithium batteries are 2.6v after sitting with no main battery in the car for over a month. Everything on the cluster works just fine but I am getting battery drain, about ten days and it's flat but driven every few days it is fine and starts first turn.
Would this be OK as I don't really want to mess about changing perfectly good batteries.
When my batteries were replaced one was zero volts the other was 2.6v apparently 2.6 volts is flat, like you my instruments all worked ok although i had to reset the service lights each time the main car battery was low, apparently bad si board batteries can cause a high parasitic drain on the system , I would certainly replace the si batteries, when new the batteries are about 3.3 volt. pull the blue plug off the cluster and see what readings you get.
I think it drains the battery cos your car is trying to charge up those fucked si batteries.
Re: Parasitic drain
Posted: Wed Sep 01, 2021 5:11 pm
by e30-wheels
onthames wrote: ↑
e30-wheels wrote: ↑Mon Aug 30, 2021 6:44 pm
Blanca wrote: ↑Mon Aug 30, 2021 4:15 pm
Being a bit paranoid I checked my batteries and the CR14250 SE 3v Lithium batteries are 2.6v after sitting with no main battery in the car for over a month. Everything on the cluster works just fine but I am getting battery drain, about ten days and it's flat but driven every few days it is fine and starts first turn.
Would this be OK as I don't really want to mess about changing perfectly good batteries.
When my batteries were replaced one was zero volts the other was 2.6v apparently 2.6 volts is flat, like you my instruments all worked ok although i had to reset the service lights each time the main car battery was low, apparently bad si board batteries can cause a high parasitic drain on the system , I would certainly replace the si batteries, when new the batteries are about 3.3 volt. pull the blue plug off the cluster and see what readings you get.
I think it drains the battery cos your car is trying to charge up those fucked si batteries.
Yep thats normally it, in my case although it did reduce the drain a bit there was another unknown fault in the si board. Your car looks the same as mine 1985 4 door, white
but i have bbs wheels, i have a set of wheels same as yours with new tyres on they were reconditiond about 5 years ago and never used, i was about to put them on e bay just thought i would mention it, if and when you get to sort your si board i my have spare you can borrow to check against yours also somone that can supply and fit batteries for £28.00, im in Battle nr Hastings.
Cheers
Re: Parasitic drain
Posted: Sat Sep 04, 2021 12:33 pm
by Blanca
I like the 'bottle top' wheels rather than the BBS, and easier to clean too, I have total of 7 of them.
Re: Parasitic drain
Posted: Mon Sep 06, 2021 1:00 pm
by e30-wheels
e30-wheels wrote: ↑Tue Aug 24, 2021 6:39 pm
Parasitic Drain 325 e30
Over the last couple of years my battery when connected goes flat after about two week of not starting the car, finally got round to try and find the problem.
I'm getting a drain of 90.20mA done all the fuse meter checks and isolating of various components to no avail except for fues 21, although i was not having a problem with the instrument cluster i disconnected the blue plug and the 90ma drain reduced to 2.2mA.(Central locking) checked the batteries which were low and had them replaced, reconnected the cluster now i'm getting a drain of 70.2mA removing the fuse for central locking lowers the drain to 68mA, if im correct im looking for 35 to 40 mA dont know what else to check help badly needed
Many thanks in advance
Update on Parastic drain
Car has not been started for about 10days, i started it today it was just like having a new battery it looks like problem has been sorted.
Re: Parasitic drain
Posted: Thu Sep 16, 2021 1:53 pm
by Blanca
Just fitted a new pair of batteries to the instruments, very easy job and I even remembered to move the jumper over and back when doing it. Lets hope tat helps with battery drain, will soon see.
Re: Parasitic drain
Posted: Thu Sep 16, 2021 8:46 pm
by e30-wheels
Blanca wrote: ↑Thu Sep 16, 2021 1:53 pm
Just fitted a new pair of batteries to the instruments, very easy job and I even remembered to move the jumper over and back when doing it. Lets hope tat helps with battery drain, will soon see.
I have my fingers crossed for you.
Re: Parasitic drain
Posted: Sat Sep 18, 2021 12:33 pm
by Blanca
First trip out yesterday and all seemed OK until I looked at the vac' meter, it wasn't working and the tacho was bouncing about 100rpm, so need to check that out.
Re: Parasitic drain
Posted: Sat Sep 18, 2021 1:16 pm
by e30-wheels
Blanca wrote: ↑Sat Sep 18, 2021 12:33 pm
First trip out yesterday and all seemed OK until I looked at the vac' meter, it wasn't working and the tacho was bouncing about 100rpm, so need to check that out.
Could be a dry jointon the battery soldering, the electronics engineer told me when he did mine you have to use the correct solder and flux because the tabs on the batteries are stainless steel the flux is an acid flux the solder is one with a silver content in it.
Re: Parasitic drain
Posted: Mon Sep 20, 2021 11:45 am
by Blanca
e30-wheels wrote: ↑Sat Sep 18, 2021 1:16 pm
Blanca wrote: ↑Sat Sep 18, 2021 12:33 pm
First trip out yesterday and all seemed OK until I looked at the vac' meter, it wasn't working and the tacho was bouncing about 100rpm, so need to check that out.
Could be a dry joint on the battery soldering, the electronics engineer told me when he did mine you have to use the correct solder and flux because the tabs on the batteries are stainless steel the flux is an acid flux the solder is one with a silver content in it.
I don't think that's the problem as these FDK batteries came with the tabs tinned, not bare stainless.
Re: Parasitic drain
Posted: Mon Sep 20, 2021 1:41 pm
by e30-wheels
Blanca wrote: ↑Mon Sep 20, 2021 11:45 am
e30-wheels wrote: ↑Sat Sep 18, 2021 1:16 pm
Blanca wrote: ↑Sat Sep 18, 2021 12:33 pm
First trip out yesterday and all seemed OK until I looked at the vac' meter, it wasn't working and the tacho was bouncing about 100rpm, so need to check that out.
Could be a dry jointon the battery soldering, the electronics engineer told me when he did mine you have to use the correct solder and flux because the tabs on the batteries are stainless steel the flux is an acid flux the solder is one with a silver content in it.
I don' think that's the problem as these FDK batteries came with the tabs tinned, not bare stainless.
Like mine and before you replaced the batteries did you say in an earlier quote that the tacho and vac meter were working, just a thourght you have got the neg and pos correct on the new batteries, i did read somewhere that some batteries the tabs are fitted diffently and you have modify for the neg and pos to be correct to the board.
Re: Parasitic drain
Posted: Wed Sep 22, 2021 12:08 pm
by Blanca
Batteries have two + pins and one neg pin, cannot fit wrong.
Everything worked just fine before.
