Battery discharge

Author
Discussion

DuraAce

4,240 posts

161 months

Monday 30th January 2017
quotequote all
GTIAlex said:
Pulled each fuse one by one and no changes. Got to go round and check all the earth points tomorrow.

Been going through all the wiring from the alternator to the battery so its all starting to look a lot healthier just need to fine the source of the drain.
All fuses? Sucking eggs here but don't forget many cars have more than one fusebox.
Did you do all the relays as well?
Have you disconnected the alternator?

GTIAlex

Original Poster:

1,935 posts

167 months

Monday 30th January 2017
quotequote all
Will disconnect the alternator tonight.

And yeah it's a fairly old van (1986 vw t25) so not a whole lot in the way of electronics and fuses.

Did all the relays up front but still need to check the ones in the bay.

TooMany2cvs

29,008 posts

127 months

Monday 30th January 2017
quotequote all
GTIAlex said:
Will disconnect the alternator tonight.

And yeah it's a fairly old van (1986 vw t25) so not a whole lot in the way of electronics and fuses.

Did all the relays up front but still need to check the ones in the bay.
Does it have a leisure battery and split-charge relay?

GTIAlex

Original Poster:

1,935 posts

167 months

Monday 30th January 2017
quotequote all
TooMany2cvs said:
GTIAlex said:
Will disconnect the alternator tonight.

And yeah it's a fairly old van (1986 vw t25) so not a whole lot in the way of electronics and fuses.

Did all the relays up front but still need to check the ones in the bay.
Does it have a leisure battery and split-charge relay?
It does but i've eliminated them from the system which made no change.


bearman68

4,662 posts

133 months

Tuesday 31st January 2017
quotequote all
I've been thinking about this in work today. I was going to suggest it was the CAN system waking all the ECU's up, and then you said it was a 1986 T5.
I'm really stuck - if you have pulled All the fuses out, and that's made no difference, it can only be something connected directly to the battery - Alternator and/or started motor.
(Actually just thinking about that - if it's a petrol, is there a permanent supply to the coil that's not switching, or an ignition relay that's sticking closed, is it possible somebody has wired in the aftermarket radio badly, and that's causing the issue) 2amps is a load of current to be going somewhere

GTIAlex

Original Poster:

1,935 posts

167 months

Tuesday 31st January 2017
quotequote all
bearman68 said:
I've been thinking about this in work today. I was going to suggest it was the CAN system waking all the ECU's up, and then you said it was a 1986 T5.
I'm really stuck - if you have pulled All the fuses out, and that's made no difference, it can only be something connected directly to the battery - Alternator and/or started motor.
(Actually just thinking about that - if it's a petrol, is there a permanent supply to the coil that's not switching, or an ignition relay that's sticking closed, is it possible somebody has wired in the aftermarket radio badly, and that's causing the issue) 2amps is a load of current to be going somewhere
Ive got a few more fuses and relays to go (found some more) so will report back.

Added a new earth today from the starter motor bolt to the body so try and eliminate earth issues and ordered a replacement for the factory gearbox to chassis earth strap.


Plan of attack is:
Remaining Fuses
Remaining Relays
Alternator
Starter Motor
Pull Hair out
Recheck fuses and relays again
Rip leisure unit out and replace with modern item (was planning on doing this anyway)
Pull hair out some more


GTIAlex

Original Poster:

1,935 posts

167 months

Thursday 2nd February 2017
quotequote all
Okay so for those of you sitting there all tense wondering how i'm getting on...I found the source.

The alternator.

The alternator that was fitted on the 6th May 2016.



bearman68

4,662 posts

133 months

Thursday 2nd February 2017
quotequote all
Pleased you've found the source. It will be a diode gone down in the alternator diode pack - a new diode will be about £1 if you can be arsed to pull it apart and find the bad one. Tempting eh?

GTIAlex

Original Poster:

1,935 posts

167 months

Thursday 2nd February 2017
quotequote all
bearman68 said:
Pleased you've found the source. It will be a diode gone down in the alternator diode pack - a new diode will be about £1 if you can be arsed to pull it apart and find the bad one. Tempting eh?
Or just claim in the warrenty and get another new one

bearman68

4,662 posts

133 months

Thursday 2nd February 2017
quotequote all
Agh, got me there.

GTIAlex

Original Poster:

1,935 posts

167 months

Thursday 2nd February 2017
quotequote all
I didn't actually sort the wiring out on the van so its going back to the chap who did on Monday to double get it all but im preparing to whip the alternator back out after just fitting new belts etc.

Bit of a pain because the water pump belt and pully has to come off before hand but only a few bolts at the end of the day, doesnt get much simpilar than 80s diesel engines