Proper PV Extension Wire for MC4 Connectors?
I have (2) 120 watt solar panels that come with 3 foot 4mm MC4 connector cables and these cables are rated at double-insulated 12 gauge wire at 25 amps throughput. I want to connect the solar panels first in series to see what the output effect will be on a 30 amp MPPT Charge Controller connected to a single 35 amp-hour SLA/AGM 12 volt Battery. The 30 amp MPPT charge controller can regulate 12, 24, and 40 volt inputs. It can also accept up to 6mm wires (10 gauge). Both solar panels have maximum outputs of 8 amps and 22 volts each. I also want to then connect them in parallel to test the power output on the same 30 amp MPPT charge controller and 12 volt battery. The question is can I use 6mm PV Extension Cable (10 gauge) Wire to connect from the panels (12 gauge) to the 30 amp MPPT charge controller and then connect THHN 10 gauge wire from the charge controller to the 12 volt battery as well as use the same type THHN 10 gauge wire to connect to a 500/1000 pure sine wave inverter? The total distance from the solar panels to charge controller, battery, and inverter would be approximately 10 feet. I expect some voltage drop and that is why I am asking whether 10 gauge MC4 connector/pv wire can be connected to 12 MC4 connector/pv wire as well as using regular 10 gauge THHN single-insulated wires from the charge controller to the battery and loads (i.e., inverter). As we know 10 gauge wire has approximately 30 amp protection and 12 gauge wire has approximately 25 amp protection. By the way, the pure sine wave inverter is protected by a 40-amp fuse. In other words, should I basically keep all series and parallel wiring test scenarios above at 12 gauge solar PV cable (4mm)?