I have a battery drain problem. I have a constant drain of about 72 -73 mA. I started by pulling the fuses. If I pull fuse 5 there is NO drain 0 mA. I check the ground cable connections including near brake pedal. (With disconnected ground cable near brake pedal there is still a drain of 72 mA). After 2 day and narrowing down the problem. I'm a bit closer to narrowing down the drain. If I pull out the connector C-1 (Blue) from the instrumentation cluster, the drain on the battery is about 7 mA. What does the C-1 connector power? Do I have a faulty cluster? Any suggestion are greatly appreciated.
I have a '84 533i.
Does any one know, whats a regular/usual drain on the battery?
Picture below shows the connector C-1 (Blue). Not sure where the single blue/white wire connects too. It was not connected at all when I pulled the cluster, comes out of the same wire bundle as the C-1 wires. (Single wire located to the right of the blue connector in the picture).
PLEASE HELP.
Last edited by My E 28 533i on Apr 19, 2011 4:25 PM, edited 1 time in total.
Regular draw should be less than 50 mA and I think the average is somewhere around 25 (mine was around16-18 when normal). I just went through the same and fortunately got it resolved.
I cannot help with what the blue clip is for though. Hopefully you get this resolved soon, I know how big of a PITA it is trying to figure electrical crap out.
The Blue connector has lots of stuff hooked up to it. I'll list em here, just for you:
find a post by a, open it, go to his signature and click the link to the ETMs and get the ETM for your car. then you can go to the pages on the instrument cluster and see what each of the C-1 connection are to and from.
ETM=Electrical Troubleshooting Manual, exactly what you need to answer this question. I only have one for an 86.
I've looked through the ETM. Its hard to narrow down the drain. A lot of power distribution coming from connection C-1.
I've read that the cluster has a battery in it and its common for it to leak/oxidize. Does my cluster also have a battery ('84). If so could it be possible that the battery created a short.
I see suggestings that 50ma is ok, but my experience has been more like 10-20, 50 is awfully high. Power locks and or the heater in them can be a hard one to pin down, but a problem, otherwise the likely suspects are aftermarket stereos, glove compartment and trunk lights. Occasionally power antenna. It's a PITA sorting it all out, but just approach it methodically, one step at a time.
The radio is unplugged, so is the antenna, and the glove box light never worked and i pulled out the bulb just in case. For the power door locks and the heater door locks can i just pull the door cards and unhook the connector (is there a different method?). I've done the drive door that way today. still the same issue. Next is the passenger door.
PS. I agree that 50 mA is way TO much. at that rate you'll drain your battery in a week. that crazy.
I've never known that 50mA to be too much. It always sounded normal to me. A relay coil will draw 150mA so I'd say that draw is the keep alive stuff like SI board charging, OBC clock, etc.
Any specs that would indicate normal draw on these cars?
50mA is more of a common reading on newer cars with more memory stored while shut off. After all my issues were resolved I was reading a 16-18 mA draw with car off.
Don't worry about the door lock heater (only one, on the driver's side) as it will damn near blister the paint and suck that battery dry very quickly. Now if you are experiencing this kind of heavy draw, then look into it. The heater is a C-clip around the door lock. That area gets HOT when the control fails and the heater is on all the time.
Blue Shadow wrote:Don't worry about the door lock heater (only one, on the driver's side) as it will damn near blister the paint and suck that battery dry very quickly. Now if you are experiencing this kind of heavy draw, then look into it. The heater is a C-clip around the door lock. That area gets HOT when the control fails and the heater is on all the time.
That's what I figured but I still unplugged the connector just in case. Regarding the auto door locks, should i check all the doors or the driver door is sufficient?
My E 28 533i wrote:
I've read that the cluster has a battery in it and its common for it to leak/oxidize. Does my cluster also have a battery ('84). If so could it be possible that the battery created a short.
David.
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
My E 28 533i wrote:
I've read that the cluster has a battery in it and its common for it to leak/oxidize. Does my cluster also have a battery ('84). If so could it be possible that the battery created a short.
David.
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
PROBLEM SOLVED. It was the 2 AA batteries inside the cluster. They were creating a short, hence the extra 60 mA (Constant discharge). Replaced with new rechargeable duracell batteries.
Now a discharge of 16mA.
Last edited by My E 28 533i on Nov 30, 2011 9:05 AM, edited 1 time in total.
clangpap wrote:
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
This more than likely just solved my battery drain dilemma. Good thing I've got some rechargeable AA's laying around.
clangpap wrote:
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
This more than likely just solved my battery drain dilemma. Good thing I've got some rechargeable AA's laying around.
I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
clangpap wrote:
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
This more than likely just solved my battery drain dilemma. Good thing I've got some rechargeable AA's laying around.
I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
clangpap wrote:
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
This more than likely just solved my battery drain dilemma. Good thing I've got some rechargeable AA's laying around.
I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
clangpap wrote:
Yes your cluster has 2 AA batteries - likely very dead if they've never been replaced. If your service lights won't stay reset - the batteries are dead. As for the SI batteries causing a short, I don't know but I have never heard of it.
This more than likely just solved my battery drain dilemma. Good thing I've got some rechargeable AA's laying around.
I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
Yup, some boards have Lithiums.
Is there a special way to remove these? The metal contacts seem to be stuck to the battery and I do not want to put too much pressure and break them. Especially break them off the board. Anyone else had this problem? Thanks.
packman21 wrote:I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
demetk wrote:Yup, some boards have Lithiums.
packman21 wrote:Is there a special way to remove these? The metal contacts seem to be stuck to the battery and I do not want to put too much pressure and break them. Especially break them off the board. Anyone else had this problem? Thanks.
You don't pry the metal tabs off the batteries (they're welded on) - you desolder the tabs from the board. To do this you use either solder wick or a solder sucker. You'll have to improvise when you install new batteries. If you're lucky you can find them with tabs already mounted. Check the voltage across the batteries before you do this.
You should see around 3V across each battery. If you do, the batteries are fine. Even though they aren't rechargeable, they usually outlast the original NiCd cells several times over.
packman21 wrote:I have 2 batteries that are not AA's. They look more like camera batteries. They are Sanyo Lithium batteries. Unless I'm missing the AA's somewhere? I am having a battery drain issue myself and thought I'd change out these batteries first.
demetk wrote:Yup, some boards have Lithiums.
packman21 wrote:Is there a special way to remove these? The metal contacts seem to be stuck to the battery and I do not want to put too much pressure and break them. Especially break them off the board. Anyone else had this problem? Thanks.
You don't pry the metal tabs off the batteries (they're welded on) - you desolder the tabs from the board. To do this you use either solder wick or a solder sucker. You'll have to improvise when you install new batteries. If you're lucky you can find them with tabs already mounted. Check the voltage across the batteries before you do this.
Thanks Ron. I decided to put the cluster back in the car since you mentioned the 3V Lithium batteries will out last the car and do not leak like the AA's. Thanks for the help.
You should see around 3V across each battery. If you do, the batteries are fine. Even though they aren't rechargeable, they usually outlast the original NiCd cells several times over.
I killed a battery after just 1.5 years. My chassis is pulling .15V with the engine off, key off. Is this normal parasitic loss? I think this is 150 Mamps but hey, electronics is a dark art to me so please educate me.
Ah, hang on, let me clarify. I see a .15V difference between the battery in the car, terminals connected, with everything off and the battery out of the car with nothing connected. I don't know if a .15V difference in this example means anything. But in my brain this is how you test for a possible parasitic loss. How am I doing?..please tell me I suck at electrical stuff. Thats ok.. But hey. I totally rock a sewing machine
It was the 2 AA batteries inside the cluster. They were creating a short, hence the extra 60 mA (Constant discharge). Replaced with new rechargeable duracell batteries. 
