Help troubleshooting RV system!

[Sparkle]

The solar panels on our camper van are no longer charging the battery. I am new to this and would be very grateful for advice on how to troubleshoot the system.

I have measured the voltages below with a multimeter straight of the panel cables. Unfortunately the multimeter I have has a broken fuse so l have not been able to measure the amps yet. Maybe it would be a better idea to pick up a resistor and use ohms law to calculate the current?

We have two 160 W flexible panels. They are rated to 26.6 nominal Voltage. Yesterday was an overcast day and I measured the following voltages.

Panel A
Fluctuated between 10-18 Volt

Panel B
Showed a consistent 26,6-26,7 V with short fluctuations downwards 20-22 V

I would think that since they show different values at least one of these panels is broken? My guess is that panel B is done for?

I opened the little cable box up on the panel but that is full of some sort of hard foam, I doubt I could get at the diode that probably lies therein without breaking stuff.

It also seems that panel A is not working as it should. We have a display for the solar regulator and this has been greyed out the last week despite some very sunny days. I have seen the display turn on a few times, but the amperage was at zero.

The solar regulator, a Votronic 350 duo, does not display any charging diodes, only the light for no charge, usually displayed during nights, is illuminated. There could of course be something wrong with the regulator, is there some way to check the functionality it?

Our lipo battery has Bluetooth connection and it charges as expected from land and motor. Since the solar regulator does not signal that it is charging anything I feel fairly confident that the battery is not at fault.

Might ad that the solar equipment is only a few years old, so super annoying to have these issues.

Anything else I should check before I start spending my money on new stuff?

 

[chrisski]

Recommend unplugging panel A and see if the system charges.

If the system is setup 2p, then this will work. If it’s set up 2s, this won’t.

Can you measure panel voltage into the volttonics when the sun is shining?

A charger will need around 18 volts at least to charge the 12 volt system. Panel a is not providing that.

If the system is setup 2s then setting it up 1 s and removing panel a should get it going.

 

[mikefitz]

You could have either panel or controller issues perhaps even battery problems.
The Voltronic controller has a replacable fuse, have you checked that?
Flexible solar panels have a short life, output gradually reduces and failures occur in the panel, often the panel shows burn marks on the reverse. Voltage alone is not a reliable indicator as the panel internal faults may inhibit current flow. Two years is typical life.

First task is to check all connections and voltages at the controller. Disconnect the feed to the vehicle battery. With no solar connected, disconnect and reconnect the house battery.

Test the panels individually connected, as suggested to the controller, and review the result.

To test independent of the controller, connect each panel directly to a 12v battery ( that is not delivering power) , either your house or vehicle battery, use a 10 amp fuse (or near value, 7.5, 15) in series with the positive. Your meter, set to volts to monitor the battery voltage. You should see a gradual increase in volts.

To test the controller you need a current limited power supply delivering over 18 volts, or known functioning panel.

The battery with Bluetooth access to battery data should indicate any battery issues. One possible situation that may cause solar controller confusion or even failure, is BMS shutdown of the charge path. This is usually due to high charging volts.

Mike

 

[Sparkle]

Thanks for all the help! The panels are toast and I have ordered new ones.

 

[0truck0]

maybe don't get the flexible ones this time. You already know why....

 

[Tomthumb62]

Thanks for all the help! The panels are toast and I have ordered new ones.

Well you already ordered, but I'll chime in anyways. Since it sounds like you're using flexible panels, here is what I've found by using two different brands of flexible panels:

We bought 2x100W WindyNation flexible panels in 2019. Installed (screwed down with Gorilla tape across the leading windward edge on the trailer) directly onto a painted canvas/wood roof. Trailer has been stored under cover for 70-90% of each year. We removed the panels recently to apply new rubberized paint to the roof. Panels appeared fairly okay (no burn marks but we're also near the Canadian border so it doesn't get all that hot here) and still produce to spec. We wanted to add more panels, so bought 2x100W Sunpower flexible panels. The Sunpower ones are bigger and clearly much better made. Even had one rip off the roof at highway speeds, hanging on by the wires and a single bolt and it survived just find, just a little banged up. Not sure the WindyNation ones would survive such abuse.

I think the key to extending the life of flexible panels is: 1) install them somewhere permanent, don't be moving them around much and 2) if on a mobile surface like an RV, keep them covered or protected from the sun when you're not using them. UV is always tough on things and especially expansion/contraction of heat/cold. Especially don't let snow build up on them, I'm sure that's a quick death to many panels because as the snow melts (then re-freezes at night), water can seep in to nooks-crannies-microcracks then freeze and make those microcracks much bigger (rinse and repeat over a winter or two and the panels will be toast for sure).

When the Sunpower ones first came out, they were very expensive. The price has come down so much, it's not that much more expensive over very budget brands like the WindyNation ones. 2x100W Windynation goes for $250/free shipping but I think we had to pay tax. We got 2x100W Sunpowered flexibles and after 10% off coupon discount, we paid $358, free shipping no tax. We will be replacing the Windynation ones with two more Sunpower ones once the WN ones croak.