My BE550G battery just died in my son's setup. I plugged the plugs into the other side of the UPS that is just surge suppressed and it is running now. My other 2 are still working. These were purchased in early 2010 as best I can tell from my old posts here. No battery has ever been replaced in them during the last 8 years. I find the UB1280 in several configurations. The 7ah is what came in it. There is an 8ah that fits right into it so that it will run 14% longer than the 7ah. The 9ah will not fit. It is 1/16" thicker and so it will not slide in the slot in the UPS. One other thing I found was that different sellers use the F1 or F2 terminal to connect with, The F1 is 0.187" wide and the F2 is 0.250" wide. I felt sure I had read this in some reviews on Amazon. Indeed , using the F1 connector caused problems for a few posters. I ordered 3 of them with 8ah and the F2 connection. Check all specs before ordering a replacement for these since the slot they fit in is snug.