My panels are patially shaded.

bc buck

I messed up on my install. I fabricated mounts to tilt my panels at 42 degrees. I screwed them down between ribs of roofing material and looks like a clean professional job. Now two of the three Kyocera KD 145sx-ufu in series are 25% shaded from panel in front of it. Dont really want to get on the roof till Spring to remount panels. How much power loss should I expect till Spring.

BB.

The shaded panels will output near zero useful current during the times they are shaded.

-Bill

Estragon

@BB - assuming the panels are mounted in landscape mode, is it possible he might get around half output, or would all the cells be wired in one series string per panel?

DConlyGuy

as bill said a shaded panel is pretty much useless, even one shaded cell can bring a panel down 

BB.

These cells all are in parallel (it looks like 36 cells in series for Vmp~18 volts). You cannot limit shading to a subset of cells and reduced the effect of the shading.

Conceivably, you could put the three panels in series with an MPPT charge controller on a 12 or 24 volt battery bank. And if you limit the shading to just once 9 cell vertical (or horizontal) row--That would reduce the panel Vmp to ~13.5 or ~9 volts (bypass diodes, assuming 4 of them, could be just 2 also--you need not open j-box to see). But I suggest that running current through bypass diodes for long periods of time is not great either (diodes get hot, very little cooling in a solar panel J-Box, hot diodes will eventually fail).

Otherwise, there is nothing you can do that will really help other than "removing the shade".

-Bill

bc buck

BB. said:

These cells all are in parallel (it looks like 36 cells in series for Vmp~18 volts). You cannot limit shading to a subset of cells and reduced the effect of the shading.

Conceivably, you could put the three panels in series with an MPPT charge controller on a 12 or 24 volt battery bank. And if you limit the shading to just once 9 cell vertical (or horizontal) row--That would reduce the panel Vmp to ~13.5 or ~9 volts (bypass diodes, assuming 4 of them, could be just 2 also--you need not open j-box to see). But I suggest that running current through bypass diodes for long periods of time is not great either (diodes get hot, very little cooling in a solar panel J-Box, hot diodes will eventually fail).

Otherwise, there is nothing you can do that will really help other than "removing the shade".

-Bill

Bill do you think diodes and panels would be OK till March. I hate to take chance in below freezing weather here in Missouri.

BB.

Are the panels in parallel?

Is this a 12 volt battery back?

If yes to both questions, then there should be no problem. The shaded panels just will not supply any useful current.

-Bill

bc buck

BB. said:

Are the panels in parallel?

Is this a 12 volt battery back?

If yes to both questions, then there should be no problem. The shaded panels just will not supply any useful current.

-Bill


3pc 12v panels in series using MPPT charger on 12v bank.

BB.

Not my favorite for shade. Cold weather will help the diodes.

And if any panels fail, there is always the mfg's warranty.

-Bill