Can I connect 3 more panels of the same size to each mc4 connector on the controller.
asked
I have a 150/100 mppt mc4 charge controller. I am wishing to upgrade my system which is currently 3 x315w 36 volt panels charging an 1040 amp 12v battery bank. I will be converting bank to 24v.
My recommendation would be to run 2 strings in parallel (each connected to a separate MC4 connection on the MPPT), with each string consisting of 3 panels in series.
As long as you don't exceed the input voltage limit (150v max) or the input current limit (70A max & 30A per MC4 connection) for your 150/100 MPPT, then you can basically connect as much solar as you want.
Just be sure to refer to the Voc voltage for your solar panels when making this assessment and leave at least a 5-10% buffer to account for even higher voltages possible in cold weather.
