I didn't realize my solar panel was bad until I bought a replacement Renogy controller. To their credit it worked with a reverse polarity error code when connected to my Renogy 50W solar panel. Then the fun began with supporting Renogy products. Besides being a terrible and huge waste of time. By the time I got to the point where I had to give up, I had already gone through the Amazon return window. Revain went ahead and accepted this defective product.