BatteryJack inc. RBC21 UPS replacement battery for APC BackUPS BF250 BF280 BF350

Compatible APC BackUPS Models

The BatteryJack RBC21 replacement battery fits APC BackUPS BF250 BF280 and BF350 units. It uses advanced AGM technology with sealed construction to prevent electrolyte leakage in any orientation. The maintenance-free design requires no water checks during its expected 4-7 year service life. This unit is a 100 percent OEM replacement for the original RBC21 cartridge.

Straightforward Cartridge Swap

Installation involves opening the UPS battery compartment and disconnecting the old cartridge before connecting the new one. The sealed AGM design means the battery can be handled in any position without spill risk. The main issue occurs when users forget to fully seat the connector or leave the compartment door unlatched. No tools are typically required beyond a screwdriver for the cover screws.

Three-to-Seven Year Float Life

The battery delivers reliable backup runtime for the supported BF250 BF280 and BF350 models under normal load conditions. Gas recombination handles over 90 percent of generated gas to extend service life. It runs out when the internal plates degrade after the expected 4-7 year float period or if the UPS operates in high-temperature environments. Not suited for UPS models outside the listed BF series or for applications demanding longer cycle life than AGM chemistry provides.