MPTT solar regulator wiring on California T7

[Mashirito]

Hi everyone!!

I'm planning to install a solar panel on my T7 Beach Tour (with the factory Lifepo battery) and I’d love to hear from others who have already done it.

Have you connected the MPPT controller after the shunt of the leisure battery?

From what I understand, if the MPPT is connected directly to the battery terminals (bypassing the shunt), the system might not register the incoming solar charge – which could lead to inaccurate battery percentage readings on the camper’s screen.

On the other hand, wiring the MPPT after the shunt (so the charge current is measured) seems more complex but would ensure proper tracking of solar input and battery state of charge.

Has anyone done it the "correct" way? Any tips on where to tap into the system to ensure the onboard screen sees the solar charge?

Thanks in advance!

 

[WelshGas]

Hi everyone!!

I'm planning to install a solar panel on my T7 Beach Tour (with the factory Lifepo battery) and I’d love to hear from others who have already done it.

Have you connected the MPPT controller after the shunt of the leisure battery?

From what I understand, if the MPPT is connected directly to the battery terminals (bypassing the shunt), the system might not register the incoming solar charge – which could lead to inaccurate battery percentage readings on the camper’s screen.

On the other hand, wiring the MPPT after the shunt (so the charge current is measured) seems more complex but would ensure proper tracking of solar input and battery state of charge.

Has anyone done it the "correct" way? Any tips on where to tap into the system to ensure the onboard screen sees the solar charge?

Thanks in advance!

Wire solar power +tve to battery +tve BUT solar power -tve to a chassis earth point.

 

[Razor Crest]

With all the current issues with batteries and software, wouldn’t it be better to hold off until it’s sorted?

 

[sticky1]

Straight to the battery terminal, VW app shows the battery capacity and will reflect the solar increase in charge capacity.
It is easy to route from the roof through the grommet in the top of the rear panel behind the door, the wiring can drop down to the top of the water tank and straight into the cupboard with the batteries
I’m not convinced VW have implemented a proper shunt, I think it’s a software enabled compromise. I personally trust the Victron more than the California app data.

 

[Mashirito]

With all the current issues with batteries and software, wouldn’t it be better to hold off until it’s sorted?

I completely agree with you, but according to my dealership, my unit is not pending any software update. (It was manufactured in June 2025) Don't know if my batts will eventually get flat like many other people, but I'd rather not find out. XD

I think that any camper van should be able to be self-sufficient and not always dependent on being plugged into a campsite power while you travel. Even more if you want to connect a portable refrigerator...

Moreover, adding solar panels, should avoid any risk of deep discharge in both the camper and service batteries.

Even so, my intention is to carry out a 100% fast removable installation that does not compromise the warranty (as the VW service does not have to know it...)

 

[Mashirito]

Straight to the battery terminal, VW app shows the battery capacity and will reflect the solar increase in charge capacity.
It is easy to route from the roof through the grommet in the top of the rear panel behind the door, the wiring can drop down to the top of the water tank and straight into the cupboard with the batteries
I’m not convinced VW have implemented a proper shunt, I think it’s a software enabled compromise. I personally trust the Victron more than the California app data.

That's the way I always did in other campervans but not sure if the T7 monitoring system will reconize either the charge and de discharge from the MPTT. Did you did that way and worked?
I do always liked victron connect but just want to be sure it will not lead also to inaccurate battery percentage readings on the pilar's screen. Thanks!!

 

[Razor Crest]

I completely agree with you, but according to my dealership, my unit is not pending any software update. (It was manufactured in June 2025) Don't know if my batts will eventually get flat like many other people, but I'd rather not find out. XD

I think that any camper van should be able to be self-sufficient and not always dependent on being plugged into a campsite power while you travel. Even more if you want to connect a portable refrigerator...

Moreover, adding solar panels, should avoid any risk of deep discharge in both the camper and service batteries.

Even so, my intention is to carry out a 100% fast removable installation that does not compromise the warranty (as the VW service does not have to know it...)

Good plan

 

[sticky1]

That's the way I always did in other campervans but not sure if the T7 monitoring system will reconize either the charge and de discharge from the MPTT. Did you did that way and worked?
I do always liked victron connect but just want to be sure it will not lead also to inaccurate battery percentage readings on the pilar's

The data does reflect the charge from the solar input. It’s not real time but does go up after a night of running the fridge and then topped up by morning sunlight.