My 04 CRV didn't need a charge line but as a matter of principal I added one after a few years. Newer CRVs with more electronics need a charge line.
A 4 wire cable provides tail lights, turn signals and a ground. 6 wires gives you a charge line and a spare wire. My spare wire was connected from the toad brake lights to a cab light so that I knew when the toad brakes were applied.
If your MH doesn't have a charge line then you can add one from the ignition to the cable connector and then on back to the toad.
My current Jeep doesn't have or need a charge line. However, as a matter of principle I'll probably add one.
2009 Holiday Rambler 42' Scepter with ISL 400 Cummins
750 Watts Solar Morningstar MPPT 60 Controller
2014 Grand Cherokee Overland
Bob