Battery Drain issue

Jellybean

Jellybean

A2OC Donor
Calling any electrical expert!
My FSI has, for some time, kept flattening the battery. When the -ve lead is removed and replaced a spark is evident. Inserting my multimeter between the Battery -ve Post and the Battery -ve Lead, it shows a drain of 1.7mA.
All interior lights have been stripped out, pending upgrading. I have pulled all the fuses in the fuse board, including the lone.maxi fuse. I have pulled all the fuses in the passenger underfloor compartment. I have disconnected the Alternator Excitation Plug. Nothing has made any difference to the drain.
Am I missing something?
Any suggestions appreciated.
Of course, then I have to sort the EML being on when the ignition is switched on!

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Alarm system I've read that's been a regular suspect? Did you lock yourself in the car and let the modules sleep?
 
Thanks guys. I didn't lock myself in. However the Alarm Unit internally still squeals, until the ignition is switched on.
How do I go about sorting the Alarm Circuit? The car now has a fully charged main battery fitted.

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The alarm is a suspect, the CCU is also a good place to start, as unless it is convinced the car is fully locked, it will not shutdown supply to several circuits, that will drain current.
I drafted out some guidance, haven't finished it yet, but have a read, and let me have any comments.

Most importantly, you need a multimeter with current, (amps), to track the cause of current drain.
The cause can be, (and quite likely is), that when the car is locked, the car's electrical system does not see it as locked, and so power to interior lights, etc, is not shut down. The CCU controls this shutdown, so is a good place to start.
Once you have the means, (a multimeter), to measure the current being drawn from the battery, use a screwdriver shaft, or similar, to enable the hatch to be “closed” without actually closing it, so that you have access to the battery. Don't lock the car at this stage.
Dissconect the battery, and connect the multimeter, set to DC current, minimum of 10 Amps range, between the battery and the battery connector.
(Excercise great care not to allow the batter cable, or multimeter leads to short to adjacent metal. A flash, a bang, blown fuses and possibly permanent damage will result if you don't).
Lock the car with the remote.
The meter will now show the current drain.
Monitor the current drain for around five minutes after locking. Make a note of the current after five minutes.
Unlock the car.
Dissconect the meter from the battery, at the battery end.
Unplug the red connector on the CCU.
econnect the meter to the battery, lock the car, and as before monitor the current for five minutes, and make a note of it.

If the current drain is now small and significantly less than the first current measurement, the CCU is the prime suspect.
Mac.
 
Thats where my knowledge ends sadly :) I think you need to disable the interior motion sensor then lock yourself in?
 
PlasticMac said:
The alarm is a suspect, the CCU is also a good place to start, as unless it is convinced the car is fully locked, it will not shutdown supply to several circuits, that will drain current.
I drafted out some guidance, haven't finished it yet, but have a read, and let me have any comments.

Most importantly, you need a multimeter with current, (amps), to track the cause of current drain.
The cause can be, (and quite likely is), that when the car is locked, the car's electrical system does not see it as locked, and so power to interior lights, etc, is not shut down. The CCU controls this shutdown, so is a good place to start.
Once you have the means, (a multimeter), to measure the current being drawn from the battery, use a screwdriver shaft, or similar, to enable the hatch to be “closed” without actually closing it, so that you have access to the battery. Don't lock the car at this stage.
Dissconect the battery, and connect the multimeter, set to DC current, minimum of 10 Amps range, between the battery and the battery connector.
(Excercise great care not to allow the batter cable, or multimeter leads to short to adjacent metal. A flash, a bang, blown fuses and possibly permanent damage will result if you don't).
Lock the car with the remote.
The meter will now show the current drain.
Monitor the current drain for around five minutes after locking. Make a note of the current after five minutes.
Unlock the car.
Dissconect the meter from the battery, at the battery end.
Unplug the red connector on the CCU.
econnect the meter to the battery, lock the car, and as before monitor the current for five minutes, and make a note of it.

If the current drain is now small and significantly less than the first current measurement, the CCU is the prime suspect.
Mac.
Click to expand...
Many thanks. A job for tomorrow now. Will check as described, and report back.

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PlasticMac said:
The alarm is a suspect, the CCU is also a good place to start, as unless it is convinced the car is fully locked, it will not shutdown supply to several circuits, that will drain current.
I drafted out some guidance, haven't finished it yet, but have a read, and let me have any comments.

Most importantly, you need a multimeter with current, (amps), to track the cause of current drain.
The cause can be, (and quite likely is), that when the car is locked, the car's electrical system does not see it as locked, and so power to interior lights, etc, is not shut down. The CCU controls this shutdown, so is a good place to start.
Once you have the means, (a multimeter), to measure the current being drawn from the battery, use a screwdriver shaft, or similar, to enable the hatch to be “closed” without actually closing it, so that you have access to the battery. Don't lock the car at this stage.
Dissconect the battery, and connect the multimeter, set to DC current, minimum of 10 Amps range, between the battery and the battery connector.
(Excercise great care not to allow the batter cable, or multimeter leads to short to adjacent metal. A flash, a bang, blown fuses and possibly permanent damage will result if you don't).
Lock the car with the remote.
The meter will now show the current drain.
Monitor the current drain for around five minutes after locking. Make a note of the current after five minutes.
Unlock the car.
Dissconect the meter from the battery, at the battery end.
Unplug the red connector on the CCU.
econnect the meter to the battery, lock the car, and as before monitor the current for five minutes, and make a note of it.

If the current drain is now small and significantly less than the first current measurement, the CCU is the prime suspect.
Mac.
Click to expand...
If it is the CCU, is it possible to just swap it over, or does another need to be reprogrammed to the car? I am sure I have a spare.

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Jellybean said:
If it is the CCU, is it possible to just swap it over, or does another need to be reprogrammed to the car? I am sure I have a spare.

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Click to expand...

Plug and play to a degree
The remote key fobs need coding to the replacement cccu also check that they are on the same transponder frequency else they will not code to the replacement cccu
Also the cccu may need coding for rear electric windows if the car it came from was different to the car it’s going into

Paul


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The soldered in ( welded? ) internal back up battery in the alarm sounder fails and leaks onto the board causing further issues. Remove it and check it before condemning the CCCU. People have fitted another type of battery but if the board has corroded its a no. A replacement working ( for now ) unit is the normal way to go.
 
When I was getting a flat battery I traced it to the boot lock solenoid and the boot light. Firstly I took the bulb out of the boot light and this solved it. I later disconncted the solenoid wire as I couldn't find a lock unit for a decent price or get into the unit to access the solenoid. Had to be careful though if I unlocked the car and opened the boot, the CCU wouldn't know and would automatically lock the doors after the 30s gap.
 
*
Foghorn said:
When I was getting a flat battery I traced it to the boot lock solenoid and the boot light. Firstly I took the bulb out of the boot light and this solved it. I later disconncted the solenoid wire as I couldn't find a lock unit for a decent price or get into the unit to access the solenoid. Had to be careful though if I unlocked the car and opened the boot, the CCU wouldn't know and would automatically lock the doors after the 30s gap.
Click to expand...
The boot light is controlled by the CCU, and if the CCU is working correctly, the boot light circuit will be switched off, once the CCU is convinced the car is fully locked.
So, what you describe may be a CCU fault.
Mac.
 
Ok, tried all the suggestions/measurements including disconnecting the red plug on the CCU. No real change, just 0.1/0.2mA.
So, maybe the Alarm unit?
Where do I locate this, and is removal simple?

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Jellybean said:
Calling any electrical expert!
My FSI has, for some time, kept flattening the battery. When the -ve lead is removed and replaced a spark is evident. Inserting my multimeter between the Battery -ve Post and the Battery -ve Lead, it shows a drain of 1.7mA.
All interior lights have been stripped out, pending upgrading. I have pulled all the fuses in the fuse board, including the lone.maxi fuse. I have pulled all the fuses in the passenger underfloor compartment. I have disconnected the Alternator Excitation Plug. Nothing has made any difference to the drain.
Am I missing something?
Any suggestions appreciated.
Of course, then I have to sort the EML being on when the ignition is switched on!

Sent from my SM-N960F using Tapatalk
Click to expand...
Sorry I dont quite understand the - ve Post terms. Are you referring to the positive pole of the battery or what?
Regarding drain current out of the battery I would consider around 20mA or below to be reasonable.
If you have a 1.7 mA drain the battery will take satisfactorily long to discharge.
 
Joga said:
Sorry I dont quite understand the - ve Post terms. Are you referring to the positive pole of the battery or what?
Regarding drain current out of the battery I would consider around 20mA or below to be reasonable.
If you have a 1.7 mA drain the battery will take satisfactorily long to discharge.
Click to expand...
The term "battery post" is normally the actual "post" on the battery which the cables clamp to. (As in fence post).
Mac
 
I have read in the past that removal of the o/s tail lamp assembly allows access to unplug the alarm siren but never tried myself
 
Joga said:
Sorry I dont quite understand the - ve Post terms. Are you referring to the positive pole of the battery or what?
Regarding drain current out of the battery I would consider around 20mA or below to be reasonable.
If you have a 1.7 mA drain the battery will take satisfactorily long to discharge.
Click to expand...
Thanks Joga. As already pointed out the -ve Post is the negative of the 2 connection points on the battery.
I have googled Battery Drain and find the following...

A normal amount of parasitic draw for newer cars is between 50-milliamp to 85-milliamp current draw. A normal amount of parasitic draw for older cars is a reading less than 50-milliamp. Anything past these amounts indicates an electrical issue.

So the reading of around 1.1mA today would seem to be not worth chasing down?

Maybe I should have googled this at the outset! Duh!


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