In case of failure in the normal power supply, the emergency batteries model  EMUFO-40170-YY provide emergency energy to the LED fixture for a minimum period of 90 minutes. The power provided to the LED Driver is  40W. A solid state-low voltage circuit protects the battery from severe damage due to strong electric discharges and during long-lasting energy failures. When normal power supply gets reestablished, the emergency battery turns automatically into charging mode. The batteries capacity reestablishes completely in 24 hours. The integrated auto diagnosis circuit will perform monthly tests of 30 seconds and 90-seconds annually tests with the purpose to verify the charging hold-time capacity of the emergency battery.