VW T5 incorrect leisure battery status when using solar charging

[alekbe]

Hello,
I have VW California T5 2012 with two leisure batteries (Acid AGM 75Ah each).
Recently my car electrician tested both batteries with some tool and they are both healthy.
Then he mounted 3 solar panels on the roof, 100W each one, and Victron Energy MPPT Regulator Smart 100V/20A BlueTooth.
I am currently staying in Spain in one place and not turning on the engine since 4 days.
Victron Bluetooth app shows that battery status is 13.88V / 7.9A (status = float, which AFAIK means that battery is fully charged).
California display panel shows 13.5V / -7.6A (50% charged).
On California panel charge percentage drops since 4 days (it was 100% when I arrived), but it seems that it only drops during the night (because of fridge).
Also according to AGM batteries specification it seems that current battery voltage means that batteries are fully charged:



I called electrician and he told me that probably California battery charge status is calculated in a different way (not from voltage but through other system when alternator in working). Because it seems that California status drops when using energy and solar panels are off (during the night) but it does not go up during the day when solar panels are working (though it seems batteries are actually charged).

Does anyone know if this is the case?
I am little bit worried because I am hiding from coronavirus in the forest, but I need electricity and it's gonna rain for next few days .

 

[WelshGas]

Hello,
I have VW California T5 2012 with two leisure batteries (Acid AGM 75Ah each).
Recently my car electrician tested both batteries with some tool and they are both healthy.
Then he mounted 3 solar panels on the roof, 100W each one, and Victron Energy MPPT Regulator Smart 100V/20A BlueTooth.
I am currently staying in Spain in one place and not turning on the engine since 4 days.
Victron Bluetooth app shows that battery status is 13.88V / 7.9A (status = float, which AFAIK means that battery is fully charged).
California display panel shows 13.5V / -7.6A (50% charged).
On California panel charge percentage drops since 4 days (it was 100% when I arrived), but it seems that it only drops during the night (because of fridge).
Also according to AGM batteries specification it seems that current battery voltage means that batteries are fully charged:

View attachment 56200

y. he told me that probably California battery charge status is calculated in a different way (not from voltage but through other system when alternator in working). Because it seems that California status drops when using energy and solar panels are off (during the night) but it does not go up during the day when solar panels are working (though it seems batteries are actually charged).

Does anyone know if this is the case?
I am little bit worried because I am hiding from coronavirus in the forest, but I need electricity and it's gonna rain for next few days .

Try resetting the Control Panel by switching Off then On using the L lower button.
if the Roof is up then you cannot do this but you could try switching the Ignition On then Off.

To be honest I wouldn’t worry too much. The % is basically a calculation of capacity used and is not very accurate. As long as the Voltage is above 12v at dawn your good to go.

As far as Coronavirus is concerned unless you plan on hiding in the woods for the next 6 months you will be exposed to the virus and have a 80+% chance of getting it. Even after 6 months imposed isolation you will get infected. The virus is here to stay. Only vaccination will prevent you getting it and that’s 18 months away.

Quarantine really works to prevent someone who has the infection or likely to developer the infection, following contact with an infected person, passing it on to others while they recover.

Have fun.

 

[alekbe]

Thanks!
Ok I am not actually hiding, but I am on one year van trip, currently "trapped" in Spain (good place to be trapped in though) .
Anyway trying to postpone my infection as long as possible.
Cheers

 

[TripleBee]

How is the earth connection from the solar panels made? Did they put the + and - directly to one of the leisure batteries? If so, you bypassed the battery check.
The + should be connected to one of the battery +, the negative should be connected to the body of the van. That way the current will pass the battery check, and show the charge or discharge correctly.
Or that should be the theory.

 

[WelshGas]

How is the earth connection from the solar panels made? Did they put the + and - directly to one of the leisure batteries? If so, you bypassed the battery check.
The + should be connected to one of the battery +, the negative should be connected to the body of the van. That way the current will pass the battery check, and show the charge or discharge correctly.
Or that should be the theory.

But the -tve of a Leisure Battery is connected to the Van body, is it not?

I have just 1 solar panel connected to the +tve and -tve of the rear Leisure Battery. The Control Panel will show the Solar Panel voltage, current as a +tve value and the % will rise to 100%.

 

[TripleBee]

In fact it is more like this:


Here you can see that the "-" of the 2 leisure batteries are not connected to the body of the van. They are connected through a measure resistance N162.
You need to connect the - of the solar panels to the body of the van. Then the control panel will show you a better indication of charging and discharging.

 

[WelshGas]

In fact it is more like this:
View attachment 56217

Here you can see that the "-" of the 2 leisure batteries are not connected to the body of the van. They are connected through a measure resistance N162.
You need to connect the - of the solar panels to the body of the van. Then the control panel will show you a better indication of charging and discharging.

Well mine seems to work OK, and the diagram I showed is from VW’s Self Study Programme.

 

[alekbe]

Hmm not sure yet how regulator is connected to the battery (I guess it's connected to the rear one). I will try to figure it out tomorrow.

I have another question - how long it can take to discharge my starter battery if I am not turning engine at all? I mean how often should I charge starter battery with alternator to prevent discharging (I mean to prevent situation in which I won't be able to start engine)?
How often and for how long it should be charged with alternator? Will it be sufficient to just turn on engine for 20 min for example every seven days (without driving)?

 

[TripleBee]

A healthy battery can take longer than one week without charging.
Do you have start/stop? Bluemotion Technology? If so, your battery will never be fully charged.
The best thing would be to charge through a dedicated battery charger.
Or you should make an extra connection from the solar panels to the starter battery. Install a switch to switch between starter and leisure?

 

[alekbe]

No start/stop, no bluemotion.
Starter battery is brand new.
It's too late for now to make extra connection (because of coronavirus and so on)...
I guess if starter battery will die I can always switch it with one of leisure batteries and use leisure battery as starter or just charge starter battery from solar panels?
Does it matter that starter battery has same capacity (75Ah) as leisure batteries but it's not AGM?

 

[alekbe]

Or maybe if I would have very long cables I could just temporary connect leisure battery which is under driver seat with starter battery to start engine?

 

[TripleBee]

Or maybe if I would have very long cables I could just temporary connect leisure battery which is under driver seat with starter battery to start engine?

I would go for that option. If you find cables long enough.

 

[WelshGas]

Hmm not sure yet how regulator is connected to the battery (I guess it's connected to the rear one). I will try to figure it out tomorrow.

I have another question - how long it can take to discharge my starter battery if I am not turning engine at all? I mean how often should I charge starter battery with alternator to prevent discharging (I mean to prevent situation in which I won't be able to start engine)?
How often and for how long it should be charged with alternator? Will it be sufficient to just turn on engine for 20 min for example every seven days (without driving)?

I regularly park my California for 4 weeks and it still starts first time.