All emergency lighting fixtures rely on an internal battery to supply power when building electricity fails. These batteries are rechargeable, must fully charge within 24 hours, and are required to provide at least 90 minutes of illumination during a power outage, as outlined by UL 924 and NFPA life safety codes.
Types of Emergency Light Batteries
- Sealed Lead-Acid (SLA) – Common in steel, outdoor, and hazardous location lights
- Nickel-Cadmium (NiCad) – Compact and ideal for thermoplastic models
Browse Emergency Light Batteries
Sealed Lead-Acid Batteries
Most commercial emergency lights use SLA batteries due to their:
- Low cost
- High amp-hour capacity
- Reliable performance across a wide temperature range
Available in 6V, 12V, and 24V options, SLA batteries can power fixtures with remote heads or higher-wattage lamps. If your unit supports multiple lamp heads or extended runtime, selecting the right capacity battery is essential.
The 6V 4.5Ah SLA battery is one of the most common emergency lighting batteries and is available for same-day shipping.
Maintenance & Testing
Modern SLA batteries are sealed and maintenance-free. During your monthly functional test, the battery's performance is evaluated automatically. Annually, disconnect the battery and check voltage levels—fully charged batteries should exceed nominal voltage (e.g., a 12V battery should read 13.2V when fully charged).
Use a battery load tester rather than a standard multimeter for more accurate results under real-world conditions. A multimeter only shows resting voltage and may give false "good" readings.
Nickel-Cadmium Batteries
NiCad batteries are ideal for compact, thermoplastic emergency light units where space is limited. Their smaller size and lightweight construction make them perfect for low-profile, indoor use.
Browse NiCad Emergency Light Batteries
Advantages of NiCad Batteries
- Compact and lightweight
- Fast charge time (typically 3.5 hours)
- Mountable in any orientation
- Spill-proof and durable
NiCad emergency light batteries offer space-saving power in a compact form and are available for immediate shipping.
Maintaining NiCad-Powered Fixtures
NiCad batteries are sensitive to memory loss. Always allow them to reach full charge before testing. If a power outage drains the battery, let it fully deplete before recharging. Monthly push-button tests and an annual full 90-minute test ensure long-term reliability and compliance.
Battery Replacement Guidelines
Always replace your emergency light batteries with the same type:
- Battery Chemistry: Never substitute SLA with NiCad or vice versa
- Voltage: Must match the original battery
- Amperage: Must be equal to or greater than the original capacity
Using mismatched batteries can result in:
- Underperformance (dim lights or insufficient runtime)
- Component damage (bulbs blowing or circuit board failure)
Can I Replace a Lead-Acid Battery with a NiCad?
In most cases, no. SLA and NiCad batteries use different charging circuitry. SLA batteries take about 24 hours to charge, while NiCads recharge in about 3.5 hours. Also, their physical connectors differ: SLA batteries typically use screw terminals, while NiCads are often hardwired.
Conclusion
Understanding which type of battery your emergency light uses is key to ensuring performance, safety, and compliance. Whether you're outfitting a small office or an industrial facility, maintaining your batteries properly will help your emergency lighting system perform when it's needed most.