A Battery Backup Unit (BBU) provides a safety net for users who do not have an uninterruptible power supply or those with a failed uninterruptible power supply.
The BBU provides 30 seconds of runtime. If ac power is not restored within 30 seconds, the system immediately goes into a controlled shutdown.
Systems 620, 640, 650, 720, 730, 740, 830, SB1, SB2, SB3 are equipped with a BBU.