After 14 months of sporadic use to power a portable cooler, the device died. I called Schumacher who told me the unit had a 12 month warranty and mine had been out of warranty for 2 months. I tried replacing the fuse which blew immediately. There was a short somewhere. Rather than take another chance with Schumacher, I ordered another model transformer that works fine. It remains to be seen how long this new power supply will last.