I've been running a residential WiFi router, fibre modem, and a VoIP phone base off one of these for about 3 years, and found this UPS to work well on a couple occasions to keep the Internet connection going like when electricians were working on wiring in the house. Today, we had an unexpected power outage, and the UPS appears to have died - no lights nor the usual beeping to indicate the mains has failed. The unit was still warm when I checked on it, so I suppose it's just been wasting power for however long since something internal failed. The battery isn't supposed to be replaceable...