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Old 4th June 2020, 10:14   #1
Caulkhead
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Default Parasitic Drain??

Battery didn’t seem to be holding charge, so got a new one and put it on yesterday. All seemed fine with starting and other electrics. Went for a drive about 15 miles. Tried to start car today, not enough in battery to start, although other electronic stuff still working, interior lights etc. New battery now on charge, any suggestions welcome about what caused the discharge overnight. I was sure all electrics were off and key out etc. It’s a diesel auto, so really worried that I will be stuck if this discharge happens when away from home. Thanks
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Old 4th June 2020, 10:55   #2
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I've been caught out a couple of times thinking that the batteries have had it but in reality it was worn starter solenoids - now I know better.

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Old 4th June 2020, 11:01   #3
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I am actually in the proces of trying to figure why my 1.8 also has a battery problem:
https://the75andztclub.co.uk/forum/s...d.php?t=305244
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Old 4th June 2020, 12:01   #4
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I think there are two things to check.

1. charge battery, disconnect from car, leave a "week" test with meter. If readings are poor then you can fairly well illuminate the car.

2. using amp ampmeter with the battery connected to the car put the ampmeter in line with the positive? and test for a discharge. If you get a reading above x then may be an idea to pull fuses to see whats drawing power.

Hopefully someone can tell you what x should be and if in line with positive or neutral.


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Old 4th June 2020, 14:07   #5
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Wow, I saw the subject heading and thought things were getting personal.
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Old 4th June 2020, 14:50   #6
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Is the starter motor just clicking when you try to start the car?

First thing to check is the battery voltage with a multimeter when your car refuses to start. If the voltage has dropped below 12v then something is draining the battery. If you find the voltage is fine then that would point towards the starter motor being faulty.

If you find you have a parasitic drain, here's a good guide on how to find it: https://testmeterpro.com/parasitic-d...-a-multimeter/

If you find you're drawing to many amps, it's a matter of removing 1 fuse at a time until you see a sudden drop in amps.

When I tested our TF as I thought we had a parasitic drain on that (turned out to just be the battery) we found a very small amp draw of something like 5 milliamps from memory.

Do you have the highline satnav system with the satnav drive in the boot on the right hand side? If so this is known to keep on running after switching the car off which can drain the battery.
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Old 4th June 2020, 17:34   #7
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Quote:
Originally Posted by Caulkhead View Post
Battery didn’t seem to be holding charge, so got a new one and put it on yesterday. All seemed fine with starting and other electrics. Went for a drive about 15 miles. Tried to start car today, not enough in battery to start, although other electronic stuff still working, interior lights etc. New battery now on charge, any suggestions welcome about what caused the discharge overnight. I was sure all electrics were off and key out etc. It’s a diesel auto, so really worried that I will be stuck if this discharge happens when away from home. Thanks
You say---battery empty---How do you know ??? Did you check it with a multi-meter or just assumed it was flat because the engine didn't start ?----
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Old 4th June 2020, 17:44   #8
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Quote:
Originally Posted by Rick-sta View Post
Is the starter motor just clicking when you try to start the car?

First thing to check is the battery voltage with a multimeter when your car refuses to start. If the voltage has dropped below 12v then something is draining the battery. If you find the voltage is fine then that would point towards the starter motor being faulty.

If you find you have a parasitic drain, here's a good guide on how to find it: https://testmeterpro.com/parasitic-d...-a-multimeter/

If you find you're drawing to many amps, it's a matter of removing 1 fuse at a time until you see a sudden drop in amps.

When I tested our TF as I thought we had a parasitic drain on that (turned out to just be the battery) we found a very small amp draw of something like 5 milliamps from memory.

Do you have the highline satnav system with the satnav drive in the boot on the right hand side? If so this is known to keep on running after switching the car off which can drain the battery.
Rick, the link does not seem to be working

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Old 4th June 2020, 18:16   #9
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Rick.---Not working for me too.---
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Old 4th June 2020, 19:07   #10
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Quote:
Originally Posted by COLVERT View Post
Rick.---Not working for me too.---
There you go.
Attached Files
File Type: pdf Testing for Parasitic Draw.pdf (261.6 KB, 16 views)
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