The device is connected to the building's electrical supply, which provides a constant charge to the battery. In the event of a power failure, circuitry in the fixture activates the lights, so that occupants can see to exit the building.
Which battery is best for emergency light?
Lithium iron phosphate (LiFePO4, or LFP) are very well suited for use in emergency lighting. When compared with alternatives such as nickel cadmium (NiCd) and nickel metal hydride (NiMH), lithium iron phosphate (LFP) batteries have several advantages: Energy efficiency. LFP is more efficient than NiCd in two ways.
What is emergency battery pack?
When AC power fails, the Sure-Lites Emergency Battery Pack LED (EBP) automatically switches to emergency mode. The EBP maintains illumination of an LED fixture for a minimum of 90 minutes.