How Long Do Exit Sign Batteries Last and When Should You Replace Them?

Exit signs are more than just a regulatory requirement—they are vital life-safety devices. But even the best signs are only effective if their battery backup functions reliably during power outages. Understanding battery lifespan, replacement cycles, and maintenance best practices is essential for facility managers and safety officers.  This guide explains how long exit sign batteries last, when to replace them, and how to maximize reliability and compliance.

1. Why Battery Backup Is Critical

Battery backup ensures that exit signs remain illuminated during:

• Power outages
• Fire alarm activations
• Other emergency situations

Without a working battery, exit signs may fail when occupants need them most, increasing the risk of accidents and regulatory violations.

Tip: NFPA 101 (Life Safety Code) requires emergency illumination along egress paths, and most modern exit signs are equipped with integrated battery backup to meet this standard.

2. Typical Battery Types and Lifespan

Most exit signs use sealed lead-acid (SLA) or nickel-cadmium (NiCd) batteries, though newer models may use lithium-ion for longer life.

Average battery lifespan:

• Sealed lead-acid (SLA): 3–5 years
• Nickel-cadmium (NiCd): 5–7 years
• Lithium-ion: 7–10 years

Factors that affect lifespan:

• Frequent discharge cycles (power outages or testing)
• High or low ambient temperatures
• Age of the exit sign or battery
• Poor maintenance or infrequent testing

Tip: Always check the manufacturer’s specifications for recommended replacement intervals.

3. Signs It’s Time to Replace a Battery

Exit sign batteries don’t always fail suddenly—often there are warning signs:

• Dim or flickering illumination during a test or outage
• Low-battery indicators (often a small red LED on the sign)
• Expired service date stickers

Pro tip: If any of these signs appear, replace the battery immediately to maintain code compliance and life safety.

4. Recommended Replacement Cycles

NFPA 101 and NFPA 70 provide guidance for battery maintenance:

1. Monthly functional tests: Ensure the battery powers the sign during a 30-second test.
2. Annual full-duration test: Confirm the battery lasts the required 90 minutes under load.
3. Battery replacement:
   • SLA: Every 3–5 years
   • NiCd: Every 5–7 years
   • Lithium-ion: Every 7–10 years
4. Document replacements: Keep logs to maintain compliance and support insurance requirements.

Tip: Some facilities opt for self-testing exit signs, which perform automatic weekly and monthly checks, reducing labor while maintaining compliance.

5. Maintenance Best Practices

• Keep exit signs clean: Dust and debris can affect battery performance.
• Check for corrosion: Inspect battery terminals for corrosion or damage.
• Verify charging circuitry: Ensure the charger maintains a full battery charge at all times.
• Plan replacements proactively: Avoid emergency failures by replacing batteries before the end of their service life.
• Consider LED upgrades: LED exit signs draw less power, extending battery runtime and lifespan.

7. Key Takeaways

1. Battery backup is essential for exit signs to function during emergencies.
2. Average lifespan: SLA (3–5 years), NiCd (5–7 years), Lithium-ion (7–10 years).
3. Warning signs of failure: dim/flickering lights, low-battery indicators, failed tests.
4. Maintenance: Monthly functional tests, annual 90-minute tests, and proactive battery replacement are critical.
5. Cost-effective upgrades: LED and self-testing models reduce maintenance and extend battery life.

Conclusion

Exit sign batteries are a small but critical part of a facility’s life-safety system. By understanding lifespan, replacement cycles, and maintenance best practices, facility managers can ensure occupant safety, maintain compliance, and avoid unexpected failures. Proactive battery management is a simple step that protects lives and reduces liability.  Contact Koorsen Fire & Security today to make sure that your building is compliant and safe!