The problem is many things are tied in on the opposite side of the ignition switch in different places. Key has to be off to run slides, & front shades. Key on to run jacks. I could break into the ignition line and mount a relay in front of MH. & run a #10 wire all the way back 34 ft. Or I could mount relay in back & run lighter control wire all the way back. On a PU charging a TT battery you would never ntice the problem. I could unhook the plug every time I stop. Or use a diode in the charge line. I temporarialy used a diode today and all worked ok. Hard to find heavy duty diodes while on the road. Radio Shack in Idaho had some 6 amp diodes for 75 cents each. Used 2. Al worked ok. When I get back home will make it more permanent. Still cheaper than buying a TOAD charge which basically does the same thing.