Took me an extremely long time to even find where on Amazon to get this thing exchanged as its defective. Where they then told me its past their return date and I have to go thru the manufacturer. So after many emails with CyberPower, the REP offered to exchange the unit with a new one. I had a PC and 3 monitors plugged into the Battery backup plugs and a small fan into the surge plug. The UPS would shut completely off when i turned the fan off. I also once experienced a power failure and the UPS just shut off again with an annoying beep. Would not recommend this thing !