I bought mine to use as a portable 9-volt power source. Tried to charge it fresh from the box but got a wonderful, shrill beeping sound. The help line is only open 8-5 EST and so it was a few weeks before I could call customer service. First call the representative told me that this was a feature and was supposed to beep continuously through the charging cycle.I tried another call. This time the rep told me to cycle the power several times and this should resolve the issue. It didn't. I was referrred to a service center some 150 miles from my home, but discovered online that there is a service center within 5 miles... whew!Not happy with this purchase, nor with service after the sale.