Amperage issue on 2S2P array

[Andrewh04wpg]

I have a 2S2P array and have tested all four panels (CS6K 300MS) individually and they were all within specs for VoC (32.5) and Imp (9.24). I use a renogy MC4 branch connector to connect the two series into parallel to the controller and expected the Voltage to be 2X Voc and the Amperage to be 2X Imp (bright sunny day). I get 2X VoC but only a fraction of Imp (1 - 3 Amps) when measured at the output of the Branch connector. My EPEVER 60A mppt controller showed the same values. I disconnected/reconnected all the panel connections thinking it was a connection issue and my controller initially showed 2X PV voltage and 2X PV amperage on the PV display, but the amperage gradually went down to 2-3 amps in about 15 minutes?? Batteries were only at 24.6 volts. Very light load on at the time, just a few LED lights. Is this normal activity at the controller and measurements at the branch connector? Or indicative of a connection issue, perhaps between the panels and the controller (About 50' of 10 awg wire)? Thank you, appreciate all the trouble shooting advice.

 

[Mattb4]

Based on your symptoms it looks like a connection problem for the Y connectors. Especially the fact you obtained better results after disconnecting and reconnecting for a short while. The only other thing I can think of is your batteries are not wanting to charge and thus is limiting PV intake. You could possibly test with a larger load such as a space heater or hair dyer plugged in.

 

[Andrewh04wpg]

Based on your symptoms it looks like a connection problem for the Y connectors. Especially the fact you obtained better results after disconnecting and reconnecting for a short while. The only other thing I can think of is your batteries are not wanting to charge and thus is limiting PV intake. You could possibly test with a larger load such as a space heater or hair dyer plugged in.

Thank you, I'll try it with a larger load and swap out the branch connectors too, in that order. Cheers.

 

[Andrewh04wpg]

The measurement at the panel connector was done when disconnected from the controller. Not sure if that affects the PV output measurement, assumed it did not.

 

[Mattb4]

Isc current measurements are not all that important. Imp is where you get power.