Once i dig into this I'll think more. If that ground wire is 5' long I'll probably run a shorter one. Keeping the wires as short as possible is my goal on the winch wires. The winch came with 6 gauge wires, so Warn thinks that's enough for a 5500 pound winch. I will be able to shorten them quite a bit too. And the contactor is built in, so less wiring there. I may cut the terminal off the factory winch ground wire and combine that with an additional short ground and bolt it to the terminal of the second battery. Plus run dedicated power and ground directly from the winch to the second battery.