Regular maintenance should be carried out by the emergency light owner on a monthly and annual basis. If the 90 second or 90 minute emergency readiness test proves unsatisfactory (i.e. the light does not come on), it may be necessary to replace the Emergency Lighting Battery.
Fortunately, the maintenance involved is actually very quick and easy as most modern luminaires have a push to test switch that will provide you with an accurate battery reading. Pressing this test button activates the unit’s cut-off circuit (simulating the loss of AC power) and should trip the battery. If the battery is dead, the light will not come on. It really is that simple.
Steps to replace emergency light batteries
Step 1 — Take a screwdriver and open the housing. Most emergency lights will use a Philips head, but special hexagonal screwdriver heads will be used for certain hazardous locations on vandal-proof luminaires. It is expected that you or your maintenance department will keep the bit that came with the unit when you purchased it.
Step 2 — Now that you have removed the tray you will see a lot of wires (don’t worry it is normal). Some of these red, black, blue or white wires will lead from the AC conduit to the voltage transformer which leads to the switching circuit. One, two or several wires connect the circuit board to the battery.
Step 3 — Depending on your emergency light, the batteries will be either sealed lead acid (SLA) or nickel cadmium (NiCd) battery types; SLA looks like a baby car battery, while NiCd usually resembles a regular household AAA battery sealed in a protective plastic shrink wrap.
Once the leads are removed from the + and — contacts, most batteries will slide out of the unit. Some batteries will be installed in the wiring harness and you will also have to remove them.
Identifying the correct replacement battery
Remove the harness and battery from the housing. The first thing to note is the voltage, usually 6v or 12v. Do not attempt to use a 12v battery in a 6v emergency light and vice versa.