The 12Gb/s SAS RAID controller operates using cache memory. The Battery Backup Module ARC-6120BA-T121-12G is an add-on module that provides power to the 12Gb/s SAS RAID controller cache memory in the event of a power failure. The Battery Backup Module monitors the write back cache on the 12Gb/s SAS RAID controller, and provides power to the cache memory if it contains data not yet written to the hard drives when power failure occurs.