Battery Tender was plugged into AC outlet in upper center Battery Tender was resting on plywood surface below outlet and right next to gray inverter unit. You can see a burned stripe in the corner of plywood surface where the AC power cord was touching the plywood. Note large cables at rear of inverter - these go to a battery that is under the cover to lower left. Battery Tender 12V wires went through this same opening to the same battery. The AC output of the power inverter is not connected to camper's AC wiring. Click again for more detailed original source picture