APC Back-UPS XS Replacement Batteries Make your APC Back-UPS XS run like new again with a replacement battery set from Power Pros. Genuine APC and BTI kits include all necessary cabling, connectors, and tray - no assembly required.  These battery kits are 100% compatible with APC ups systems and come with a full 1 year warranty (APC) or 18 month warranty (BTI). If you don't see your application listed, please give us a call at 1-888-330-2538 for expert assistance.     Model Battery BX900R RBC5 (Qty 2) BX800, BX900, BX1200 RBC32 BX1500, BX1500BP RBC33