Leisure Batteries not working

[svent]

Hi

I have a 2007 Cali and am based in South Africa. There are very few Calis in SA so VW dealerships have very little expertise about the vehicles. During a recent trip I seemed to have lost power to my interior lights, pump, control panel etc when the electrical mains are unplugged and the ignition turned off. I plugged the electrical connection in to charge the leisure batteries which had both dropped to 11.4V - no luck. I then trickle charged the batteries with an alternative charger to 12.6V each and still no luck. I have checked the fuses under the passenger seat and in the dashboard console and all appears fine.

Through discussions and reading various forum posts I believe it could be the Earth Shunt problem. Could this be? If so would it still prevent the electrics from working when the batteries are fully charged? I understand it would prevent the batteries from charging.

Some other observations. When driving the G appears in the control panel and when plugged into mains the plug symbol also appears - both suggest there is still a charge to the leisure batteries.

Please could someone assist - its driving me crazy

Sven

 

[Californiaman]

So, it all works when plugged in and/or the ignition is on?

Not sure if the earth shunt could cause that - I thought that was only an issue when there was a high current draw (the heater startup current for example) I would have thought that low voltage/drain stuff like the lights wouldn't cause that.

It sounds more like a relay to me...

The camping controller / display should show the leisure battery capacity. Does it?

 

[John]

Hi Sven.

The normal symptoms with a bad earth shunt are a flickering central control display and the diesel heater not working correctly and cutting out.

Going back to basics it sounds like your leisure batteries are Ok as you charged them with an external charger and the voltage recovered to 12.6V.

However, the batteries are getting towards the end of their working life so first I would check them again after a few days to see if they are holding their charge. Next it is important to check if they have a high internal resistance which shows up by a voltage drop when they are under a load.

To test internal resistance you will need to take the batteries to a specialist who has a tester.

Next to check that the Cali charger is working (on a 2007 Cali it will only charge the leisure batteries) plug in your mains hook up lead then check the voltage across the leisure batteries. It should increase to around 13.5v.

If all the above is ok it could be an earth problem in which case I would connect a jump lead to the earth side of the leisure battery and find a good earth point for the other end of the lead.
Check if this cures the fault which would indicate an earth problem.

Finally if you need or want to modify the earth shunt there is a good document in our download section you are a club VIP so you can download it.

John

 

[svent]

Hi, thanks for your responses
Yes all the lights etc work when plugged into mains or ignition is on.

I have just done the following as a result of your posts:
- the control panel does not flicker and I don't have an auxillary heater (at least my control panel says auxillary heater not connected). This is a separate debate as I was lead to believe that if there were two leisure batteries an auxillary heater should be in the car. Where would i find it if it does exist?
- tested the batteries, still have a charge of 12.3V each. If i turn on the ignition or plug in the mains there is no change
- the control panel shows (when ignition on or mains plugged in ) that the battery is fully charged and gives a 13.5V and -0.2A reading. The voltage goes to 14.5V if I turn on lights or fridge. The batteries still however show 12.3V

Thanks
Sven

 

[Californiaman]

I believe the aux heater is mounted under the floor just by the bottom on the "b" pillar. I'm not sure what one looks like though!

When fitted, it vents via a black(?) vent at the bottom of the "B" pillar (the normal heating supplied by the engine heat uses grey vents).

If that vent isn't there then that would be a good giveaway without crawling under the van to try and identify the heater.

So, all the charging circuits are working - both from the mains hookup and the engine. That's a good start.

Still sounds like a relay to me...

 

[svent]

Thanks Californiaman
My electrical knowledge is poor, so here it goes. Can I locate the relay and test it. How would I find out if it is the cause?
Sven

 

[Californiaman]

I'd need to study a wiring diagram to work that out I'm afraid.. someone will soon come along that knows the answer no doubt.

In the meantime, Johns suggestion of ensuring you have a good earth using a jump lead to a solid point on the body is what I would try next to rule that out.

 

[Californiaman]

I've found this wiring diagram online which you may fnd useful. It doesn't help me to understand where it may be going wrong though. It doesn't mention a relay that gets switched when you go between mains/generator supply and power from the batteries.

http://www.volkspage.net/technik/ssp/ssp/SSP_329.pdf

So, that would make me think it would be the batteries as there isn't much else it could be BUT, I would be surprised that the low power requirements of the bulbs (above the sink) for example would cause enough earth leakage to prevent them at least glowing dimly!

Unless perhaps, there is NO earth at all and the mains connection is providing the earth. But if that is the case, how does it earth when the engine is running and the batteries are charging..?

Hmmmnn... interesting...

 

[svent]

Thanks again. Im going to try John's suggestion with the earth cable. Will let you know.
Sven

 

[svent]

HI
Problem solved! Decided to remove the rear leisure battery and discovered that the earthing cable had come off - the bolt had come loose. What a relief. Thanks for your input - it was an earthing issue after all. Now onto the auxillary heater - I see I do have black vents on the pillar by my drivers seat. That would be a great surprise to find out I do have the heater.
Sven

 

[John]

HI
Problem solved! Decided to remove the rear leisure battery and discovered that the earthing cable had come off - the bolt had come loose. What a relief. Thanks for your input - it was an earthing issue after all. Now onto the auxillary heater - I see I do have black vents on the pillar by my drivers seat. That would be a great surprise to find out I do have the heater.
Sven

Glad you sorted it Sven and good luck in the search for your heater.

John