Is this normal?

[SeanF1]

Afternoon all,

How common is this? Two 100w renogy panels side by side aimed at an overcast sky.

 

[Tombola]

ideally you need 2 meters to test at exactly the same time to be certain

 

[Jimbohorlicks]

What do you get when both connected?

 

[the1andonly]

Are panels clean?
i notice you say overcast.
when i did some trials with changing panel angles i found best results were when panels were flat (overcast) small cloud changes could have a large impact.
what is the VOC on the labels?
as tombola said try 2 meters then swap over both

 

[SeanF1]

Are panels clean?
i notice you say overcast.
when i did some trials with changing panel angles i found best results were when panels were flat (overcast) small cloud changes could have a large impact.
what is the VOC on the labels?
as tombola said try 2 meters then swap over both

It was very overcast but the test was done with the panels leaning against the table rather than flat. I will try that. The closed circuit amperage was the same on each panel 0.13a but the voltage difference remains even if positions swapped. Not sure what that tells me tbh. I have raised a ticket with Renogy, but no reply yet. Panels are clean.

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[the1andonly]

Was it within a 1/2 hour of sunset? In my trials i seen power and voltage drop off quickly. Currently i cant decide if its an iffy cell or collection / measurement issue.

 

[SeanF1]

Thanks all for your interest in this.
I did some more testing under load today and I'm pleased to say that both panels performed very similarly in terms of both voltage and amps.
Still very overcast. I hooked up a little rig with my old PWM controller and a motorcycle battery and took several readings on each panel.
Under load voltages averaging 13.4 and amps of 0.3 to 0.5. Also connected them in parallel and was getting 0.8 to 1 amp.
Also tested the existing panel on my roof and got almost identical readings so hoping for good things from my parallel set up when the weather brightens up.

So I think I'm OK to go ahead and fit these panels and hoping tomorrow/Friday are going to be warm enough here in the South East.
Many thanks for all your help.
Sean

 

[SeanF1]

Just to update this story, I complained to Renogy Support about this discrepancy back in late January and after some toing and froing with proving my purchase and giving the serial number of the bad panel, they have today delivered a new replacement panel.

Well done Renogy. Can't fault the service.