This is my UPS I have for my gaming PC, modem, router, and TV in case of brownouts or power loss. I have hooked up four 12v Eaton Powerware 12280 VRLA AGM batteries with two 24v series connections. It is an online server grade UPS and I replaced the aged batteries with my own batteries, so I didn't have to buy the replacement 18 Ah RBC55 batteries for around $250-300. I am in the process of setting up Powerchute Business Edition to monitor the battery voltage and the data logging of I'd I have any significant power loss. Typical automatic transfer time to the batteries is about 2ms so it allows me to comfortably run my systems without fear of improper shutdown or damage to any of the electronics.