Emergency lighting is very useful in locating the exit to a building during a power outage or some other form of emergency. Emergency lights are generally battery powered so that they work even when the power is out, but you must regularly check the batteries to ensure they're working properly. Emergency lighting is only useful if it's well maintained and the lights should always have fresh batteries in them. Changing an emergency light battery can be done quickly if you have the appropriate replacement battery handy.
Locate the emergency light battery compartment on the light. Exit signs normally have the compartment located in a space directly above the word "Exit."
Pop the compartment open manually or unscrew it with a screwdriver, depending on your individual light.
Pull the wire harness off of the battery if it has one. Otherwise, the battery is just wedged against the leads; simply pop it out.
Plug a new battery into the wire harness and insert the battery back into the compartment, or snap the new battery back against the leads.
Replace the cover and press the "Test" button on the light to verify the battery is working and the light is getting power.