Help me figure out panel issue

[Byrogie]

I have 4 of these panels

Installed (not me, apparently 2S2P) so expected max 42 volts, 18 amps) identified for experiment as 1,2,3,4. 1-2 in series, 3-4 in series then y connector parallel to controller.
Epever 100/40 controller.
Admit up front I did not monitor amps, just voltage. Operating 4 days. So yesterday controller shut down due to over voltage and tripped PV breaker. Replaced breaker today, reading first thing this morning , incoming 42 volts, 8 amps. Indicates one string only?
So, the following experiments and results:

Covered 1&2, result 18.6 volts, 13.3 amps, 200 watts

Covered 3&4, result 18 volts, 13 amps, 240 watts

Covered 1&4, result 39 volts, 3 amps, 120 watts

Covered 2&3, result 39.3 volts, 5 amps, 200 watts

All 4 open, 14.5 volts, 13 amps, 188 watts.

Good full sun all day….

Is wiring correct? I can’t meter, on Rv roof and covered wires. Installer is aware, checking for options in case he doesn’t see something.

 

[sunshine_eggo]

Incorrectly wired.

One or more failed bypass diodes in panel(s).

 

[Byrogie]

Thx I figured wiring, what did he do wrong you think? No shade for 2 days, until dusk, so still could be diodes? Disconnect happened during full sun.

 

[sunsurfer]

It would appear that 1 and 4 are in series and 2 and 3 are in series ignoring the amps. The test results are unusual. Did you let the controller track for a while or reset the panels AFTER all the testing? Those controllers have had issues tracking correctly and can get stuck at batt volts.

I would check full sun AFTER the string was disconnected and reconnected. Cover them BEFORE you disconnect/reconnect(prevents arcs). See what happens with all panels in sun(after reset)

Let us know.

 

[Byrogie]

It would appear that 1 and 4 are in series and 2 and 3 are in series ignoring the amps. The test results are unusual. Did you let the controller track for a while or reset the panels AFTER all the testing? Those controllers have had issues tracking correctly and can get stuck at batt volts.

I would check full sun AFTER the string was disconnected and reconnected. Cover them BEFORE you disconnect/reconnect(prevents arcs). See what happens with all panels in sun(after reset)

Let us know.

Thx I’ll check again tomorrow, expecting full sun again. So cover, then disconnect and reconnect panels. Should I turn controller off and on as well? I did allow 1 hour for results between tests but did not switch off/on panels.

 

[sunsurfer]

Thx I’ll check again tomorrow, expecting full sun again. So cover, then disconnect and reconnect panels. Should I turn controller off and on as well? I did allow 1 hour for results between tests but did not switch off/on panels.

You could just unhook it from the battery to reset and go from there. If its still tracking panels same as battery voltage, reset the string. Can yo physically see the panel wiring to verify? Need numbers on the battery also. Type and charging voltage. Did you have enough load to pull more then 8 amps?

 

[Byrogie]

You could just unhook it from the battery to reset and go from there. If its still tracking panels same as battery voltage, reset the string. Can yo physically see the panel wiring to verify? Need numbers on the battery also. Type and charging voltage. Did you have enough load to pull more then 8 amps?

Battery 280 a/h lithium. About 60% when started charging. Controller set for 14.2, was at 14 pushing 25 amps at start. The 8 amps was from the panels at 42 volts. Still half expected production. I did put the inverter/ charger on for a bit later on to test and it was pushing the 30 amps set point which the battery was accepting net of loads. Kept a load on the battery all day to make sure it needed amps.

 

[sunsurfer]

Is this a first run or did it work before? There is no way to see the 40ish volts without 2 wire in series. Could be a bad connection issue, panel issue, controller...etc.. at this point. Instead of covering panels, you might need to swap wiring on them to test directly and see what you get. Example, put 2 in series and try. Then try 2 others in series.

 

[HRTKD]

A bad connection can give you the correct voltage, but little or no current.

Turn off the solar charge controller. If that isn't possible then you'll have to cover the panels or wait for dark. Take apart each MC4 connector and check for good crimps. If there is any corrosion or scorching, it needs to be corrected or replaced.

On an RV, we suggest that you implement a dual pole circuit breaker to use as a switch to disconnect the PV from the solar charge controller. That allows you to work on the PV or solar charge controller side in full sun.

As @sunsurfer said, try the panels one at a time. A multimeter would help to test each panel so you can avoid multiple trips to the roof.

 

[Byrogie]

A bad connection can give you the correct voltage, but little or no current.

Turn off the solar charge controller. If that isn't possible then you'll have to cover the panels or wait for dark. Take apart each MC4 connector and check for good crimps. If there is any corrosion or scorching, it needs to be corrected or replaced.

On an RV, we suggest that you implement a dual pole circuit breaker to use as a switch to disconnect the PV from the solar charge controller. That allows you to work on the PV or solar charge controller side in full sun.

As @sunsurfer said, try the panels one at a time. A multimeter would help to test each panel so you can avoid multiple trips to the roof.

 

[Byrogie]

Connections are all covered. Looking for suggestions for installer to check.
Update today, controller wasn’t going to boost, changed boost recovery to 13.5 and then got 15 amps at 40 volts. Tells me both series strings are operating correctly.
So on next test, I covered one panel in each series string and got 17 volts at 15 amps. Which is 2 single panels operating in parallel. Should be zero?
What could be the wiring issue here?

 

[HRTKD]

So on next test, I covered one panel in each series string and got 17 volts at 15 amps. Which is 2 single panels operating in parallel. Should be zero?

Are you sure you don't have 2p2s? 2p would give you ~21 volts and ~18 amps, maximum. Then put each 2p string in series and you get ~42 volts and ~18 amps. With 2p2s, if you cover one panel in each string you would then get 21 volts and 18 amps.

The parameter change to the solar charge controller could have kicked it to rethink things. This could be a controller issue, but I would be hesitant to go down that rabbit hole until the panels are individually tested and then the connections are also tested.

 

[Byrogie]

Are you sure you don't have 2p2s? 2p would give you ~21 volts and ~18 amps, maximum. Then put each 2p string in series and you get ~42 volts and ~18 amps. With 2p2s, if you cover one panel in each string you would then get 21 volts and 18 amps.

The parameter change to the solar charge controller could have kicked it to rethink things. This could be a controller issue, but I would be hesitant to go down that rabbit hole until the panels are individually tested and then the connections are also tested.

Mmm that could be it. Can you tell anything from this pic? And in the long run would it make a difference in this application? The series seems to be paired sideways.

 

[HRTKD]

No, I can't tell how the panels are wired from that photo.

But I can tell you that never would I have come up with a wire housing implementation like that. I'm not saying it's wrong, just that it's unusual. If it works, it's not wrong. PVC does degrade when exposed to sunlight, but it takes years to have significant effect.

 

[sunsurfer]

got 15 amps at 40 volts. Tells me both series strings are operating correctly.

If thats 15amps / 40v from the panels and not battery charging at 15amps, then I agree. The panels are wired correctly and you are getting 600w. If its 15 amps into the battery at 13.5v then you are getting 200w.

Looks like you are good to go if its 15amps from the panels.

 

[Byrogie]

If thats 15amps / 40v from the panels and not battery charging at 15amps, then I agree. The panels are wired correctly and you are getting 600w. If its 15 amps into the battery at 13.5v then you are getting 200w.

Looks like you are good to go if its 15amps from the panels.

Yes from the panels. Other guys suggest panels wired 2P2S. Seems logical through testing. issue now is the controller. Probably back to your previous concern with Epever tracking. It’s always been an issue with previous FLA batteries not going to bulk properly and not maintaining float even with good sun. Lots of throwing the generator -inverter charger at it. Looking now at a Victron. Better?

 

[sunshine_eggo]

Looking now at a Victron. Better?

Downright luscious

 

[Byrogie]

No, I can't tell how the panels are wired from that photo.

But I can tell you that never would I have come up with a wire housing implementation like that. I'm not saying it's wrong, just that it's unusual. If it works, it's not wrong. PVC does degrade when exposed to sunlight, but it takes years to have significant effect.

Ya I probably won’t live that long anyway. So do you see any issues with 2P2S as long as I get what I need?

 

[HRTKD]

Ya I probably won’t live that long anyway. So do you see any issues with 2P2S as long as I get what I need?

If it works, it works. The way some people wire four panels on an RV roof is to put the panels on the curb side in series and the panels on the street side in series. Then parallel those two strings. That way the shade from an air conditioner will impact only one side.

In your case, the air conditioner is at the other end of the trailer and isn't a factor. The vent covers between the panels aren't small, but you'll have shade only when the RV is parked north/south and during early morning and late afternoon.

 

[sunsurfer]

Yes from the panels. Other guys suggest panels wired 2P2S. Seems logical through testing. issue now is the controller. Probably back to your previous concern with Epever tracking. It’s always been an issue with previous FLA batteries not going to bulk properly and not maintaining float even with good sun. Lots of throwing the generator -inverter charger at it. Looking now at a Victron. Better?

I had newer epever's and switched to Victron. They work MUCH better and tracking is fast. Some have blue tooth and the app is free. get the model with blue tooth, they have no display.