T6 hookup charging

VW Guru · Jan 29, 2019

california kid said:
Hi Vw Guru.

Do you suggest phoning tomorrow or just popping in Friday what time would you suggest as I have a meeting at 11.00 am,what time is your Lunch break as I do not want to interrupt that.

Alan

Hi @california kid give the call center a call tomorrow and get them to raise a job as far as I’m aware we have space left on Friday so any time is fine. Oh and a lunch break you must remind me what that is I’ve not had one for over 10years no time

california kid · Jan 29, 2019

Hi Vw Guru.

Will give them a call tomorrow I do know what you mean about lunch,hopefully
The guys or girls will be able to give me an appointment will see you Friday,
Fingers crossed for a easy fix, cheers enjoy the rest of your evening

Alan

Paul Roe · Jan 30, 2019

Vw guru said:
As much as what I’m about to say will annoy a lot of people I’m going to say it because there is a common misconception on this forum that the charger when hooked up charges all three battery’s it does not it only charges the leisure battery’s. The charger never has charged anything but the leisure battery’s. With the engine running the alternator charges all three battery’s engine off the engine battery is disconnected via the split charge relay from the leisure battery’s.

In @Paul Roe case for some reason the battery initially discharged that I agree needs investigating how ever the battery is now discharging rapidly because after the initial discharge the battery was never brought back up to capacity by a long term trickle charge and thus it will not ever regain full operation, modern battery’s cannot be brought back to life by driving the vehicle using the alternator the current is to high to restore a battery. I have no doubt after a full trickle charge the battery will retain its charge. Going forward however it’s life span will now be reduced as the internal plates would have suffered damage.

leisure battery at 14.4 v
current on panel down to +2.8A
voltage on starter battery has now started rising, was 12.2v now 12.8v
so sounds like it is charging the starter battery

going to see what happens overnight
I called Sheffield VW and they said it does NOT charge the starter battery

so if the starter battery ends up at 14V then i will accept that it does.

as for the negative current when you start the engine, well i guess it will do that if the starter battery is at 12.2V and the hookup charger is pushing the leisure batteries up to 14.4V

Paul Roe · Jan 30, 2019

overnight it went to 13.6V
so still trickle charging from hook up
will see what it is this evening

VW Guru · Jan 30, 2019

Paul Roe said:
overnight it went to 13.6V
so still trickle charging from hook up
will see what it is this evening

I agree it is trickle charging the starter battery as I’ve had one on test all night as well. However it’s not by design @Loz maybe correct in what he is saying and I maybe correct in what I’m saying. However vw firmly maintain the charger on hook up does not charge the main battery only the leisure battery’s. Main wiring diagram for the split charge relay also confirms this. However somewhere and some how the main battery is reciving a very small current flow when on hook up and I will get to the bottom of why. So that we all know exactly what’s happening

Nick Stubbs · Jan 30, 2019

Vw guru said:
I agree it is trickle charging the starter battery as I’ve had one on test all night as well. However it’s not by design @Loz maybe correct in what he is saying and I maybe correct in what I’m saying. However vw firmly maintain the charger on hook up does not charge the main battery only the leisure battery’s. Main wiring diagram for the split charge relay also confirms this. However somewhere and some how the main battery is reciving a very small current flow when on hook up and I will get to the bottom of why. So that we all know exactly what’s happening

There must be some stray currents somewhere as a few of us have the rear number plate lights glowing albeit dimly when parked up ?

B J G · Jan 30, 2019

I assume that the dash 12volt cigarette lighter socket is fed from the engine battery, if correct I did a check with normal ignition of and then with mains connected (ignition off throughout).
I've used my USB charger with voltage indication to see what happens. 1st photo no hookup, 2nd after mains on for a few minutes, 3rd after about an hour.

Paul Roe · Jan 30, 2019

after another whole day on HU it has only gone to 13.7v
so not the 14.5v that the leisure batteries reach

burnercan · Jan 30, 2019

Paul Roe said:
mine seems to go flat after just over 2 weeks if i dont drive it

Do you leave it unlocked by any chance? The manual says the battery will drain if it is left unlocked for extended periods.

Paul Roe · Jan 31, 2019

burnercan said:
Do you leave it unlocked by any chance? The manual says the battery will drain if it is left unlocked for extended periods.

No it is left locked

This morning still 13.7V on starter and leisure battery
so no more charge over night, looks like 13.7 is the max the Hookup will charge it to

Unplugged hookup and it dropped by 1V to 12.7V

started engine and alternator started charging at 14.5V this was not happening before, so perhaps the trickle charge has sorted out the starter battery
-4 deg and rolling up the hookup cable was like trying to roll up a dead python with rigormortis !
My Red Flash Starter Pack also arrived all 9.4kg, but I will be calling out VW Assist if it goes flat again to make sure they have a history of the problem.