I was meaning if I ordered or bought locally, just the wiring alone. I'd have to order a couple of the connectors for the new wire. Am I thinking right?
You don't have to use MC4 connectors. If you scroll up and look at my panels, I used #12 marine grade cable that was connected to the original cables with a simple two-wire connector that looks like this:
https://www.westfloridacomponents.com/J375APF09/10+Gauge+2+pin+SAE+Connector+Quick+Disconnect+Harness+Bullet+Lead+Cable+1+Ft.html
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