I had been using Battery Tenders for many years until I had one short out and burn up. The case was totally warped and very hot. I called corporate and reported the issue, they didn't seem very concerned sent me a new one. Then a week later their chief engineer called me in a panic and wanted me to send the defective unit back for evaluation but it was already tossed into the dumpster. Then I learned about desuflating process, won't use another Battery Tender gave the new replacement unit away. And I upgraded to the Battery Minder, great investment. Here is the one I bought from Amazon..