Control panel voltage accuracy

[briwy]

We've just come back from a few days away and the fridge stopped working after around two days parked up. I guess this is about right so I have been trying the 100w solar panel I have had for ages in the shed.
Its temporarily wired in through a controller to the leisure batteries but I'm seeing a big discrepancy between the voltage on the overhead display and a voltmeter across the battery terminals. 10.5v on the display and 12.4 on the meter. Tried two different meters so I' sure that's not the problem.
Has anyone else found this? Seems a bit odd so I'm wondering how accurate the display is supposed to be.

 

[Andresz]

The control panel voltemeter is dead accurate.
Perhaps you have the fuse on the baterry blown and the 2 baterries are separated now, so you measure one baterry and control panel measures the other baterry?
10.5 Volts sounds really un-healthy low.
Regards
Andrzej

 

[briwy]

Thanks Andresz.
Are you saying that there is a fuse between the two batteries or that each battery is fused separately. Wish VW would let a wiring diagram out.

 

[Alan]

I'm surprised you only managed two days use of your fridge presuming your batteries were charged before hand
Can I ask what setting your using ?

 

[Andresz]

There is a square fuse on the plus lead of the rear baterry, my guess is that the one does separate the baterries if blown.
Regards
Andrzej

 

[briwy]

OK I'll check that fuse, if it's blown then that could explain why we didn't get longer from the fridge.

Fridge was set on Max while driving to the site, about 70 miles, then dropped it to 4 on site.
Batteries were fully charged on hook up before leaving. I just leave it plugged in when at home.

 

[briwy]

There is a square fuse on the plus lead of the rear baterry, my guess is that the one does separate the baterries if blown.
Regards
Andrzej

Andrzej

There is no fuse in the rear battery lead on our 2012 cali. However there is a large 80amp fuse with the other fuses under the front seat which seems to do the same thing.
The overhead display voltage comes from the rear battery on ours whereas I was checking the voltage on the front battery under the seat. This could explain the difference, it seems to have settled down now and is nearly the same after charging.

 

[Andresz]

Andrzej

There is no fuse in the rear battery lead on our 2012 cali. However there is a large 80amp fuse with the other fuses under the front seat which seems to do the same thing.
The overhead display voltage comes from the rear battery on ours whereas I was checking the voltage on the front battery under the seat. This could explain the difference, it seems to have settled down now and is nearly the same after charging.

Hello
Seems that VW strongly sticks to decision of making each California electric circuit absolutely unique. Just like Van Gogh paintings, never the twice the same. :lol:

Anyway, good it is cleared now. If I understand well, the 2 batteries had a different voltage indeed. Was the fuse blown, or that was just standard situation with your circuit?

Regards
Andrzej

 

[Eystein007]

The control panel voltemeter is dead accurate.
Perhaps you have the fuse on the baterry blown and the 2 baterries are separated now, so you measure one baterry and control panel measures the other baterry?
10.5 Volts sounds really un-healthy low.
Regards
Andrzej

My Control panel voltmeter show 0,5V less than a Voltmeter over the laisure batteries.

 

[bathurg]

Thanks Andresz.
Are you saying that there is a fuse between the two batteries or that each battery is fused separately. Wish VW would let a wiring diagram out.

Just posting some useful information I found while digging around online to solve a similar concern I had with our 2010 T5 Cali. The fridge only lasted 3 days at a festival, and the heater only one night when winter camping. Being somewhat electrical this did not make sense to me so started poking around.

T5 wiring diagrams attached, which show the leisure batteries are actually in parallel with 75A in-line fuse mounted on the 2nd battery under the wardrobe - note the manual is ambiguous about the 2nd battery and the auxiliary heater. Sourced from:
http://www.1946vw.co.uk/vwbooks/vw_info/T5_pdfs/T5 Camper wiring 2009 onwards.pdf

I found the existing 50A battery terminal in-line fuse blown - this can happen to fuses as they age, especially if they are operated their limit. Interestingly the official wiring diagrams show a 75A fuse and is what one of the German user sites recommend... I replaced it with the following which seems to be the same unit that it was supplied with:
Pudenz CF8 75A 57V automotive battery terminal fuse
http://uk.rs-online.com/web/p/automotive-fuses/3377921/

The control panel voltmeter is within 0.2-0.5V of my multimeter reading on the battery terminal so is probably sufficiently accurate for indication purposes. Hopefully this solves our battery problem and is useful for others.

Cheers

Graeme

 

[rippers]

Mines only a couple of weeks old but I've been massively impressed with how good the battery was. Fridge on level 5, night long heating and using lights etc after two days still 90%

 

[campandfly]

Our Cali is 5 years old with original batteries. Everything is running fine.
Here are a few readings photographed
My question is how can it be that
13.1v is 100% charged and
13.8v is only 90% charged
also 14.3v drawing 0.2A is also 90%
Another anomaly is my top of the dash 12v socket shows 14.4v
and the ash tray 12v socket shows 12.4v
Its all a mystery to me.

 

[WelshGas]

Normally the Dash top socket is connected to the Leisure Batteries and the pull out 12v socket to the engine battery.
My experience is that the % calculation is not that accurate but can be reset by resetting the Control Panel or switching on the Ignition.
Lastly, the % decreases with a current draw but rarely seems to increase when the Leisure Batteries are charged using Solar Power or another form of charging. Using the built in charger seems to work, probably due the way it is wired compared with Solar.

 

[campandfly]

For 5 years I just assumed that the Dash top socket was connected to the starter battery.
So you learn something every day and of course that explains the large Voltage difference sometimes. Thank you. @WelshGas
I have noticed the %drop fairly quickly when the fridge current draw kicks in and I run it on 5 or cooler.
I will double check the voltage %increase when my solar is on. I think it does increase but not always like you say if you switch the control panel off and on and or fire up the ignition it does recalculate the %V.

So the mystery has started to unravel.

 

[WelshGas]

For 5 years I just assumed that the Dash top socket was connected to the starter battery.
So you learn something every day and of course that explains the large Voltage difference sometimes. Thank you. @WelshGas
I have noticed the %drop fairly quickly when the fridge current draw kicks in and I run it on 5 or cooler.
I will double check the voltage %increase when my solar is on. I think it does increase but not always like you say if you switch the control panel off and on and or fire up the ignition it does recalculate the %V.

So the mystery has started to unravel.

Also, on EHU you will notice the Engine Battery voltage creep up as the Leisure Batteries reach fully charged state. This doesn't happen when just using Solar. Just a small trickle charge, but useful. You can see this if you unlock the car but Don't open the Drivers door. As soon as you open the Drivers door various electrical circuits get energised ready to drive away eg; high pressure fuel pump etc;.