Good to know! I have cables with an inline 40A fuse and on/off switch. I'm looking forward to trying this supply out !I've been using the PowerMax to power my big lights for several years. I still make sure I have an inline fuse or circuit breaker between the light and the power, but have had no issues with these power supplies. There is a small switch on the side of the supply that you have to move so it supplies constant 13.8. It still works if you don't, but then it will be in battery recharge mode and the voltage it supplies will drop in stages after several minutes of operation. I have 6 or 7 of these supplies.