Search guides

Fix a backup battery that is dead

We'll confirm the battery is dead, check connections and charger, then replace the battery—or tell you when to call a pro.

Troubleshooting · Home maintenance
15–45 min
What you'll need
  • Replacement battery (match voltage and capacity)
  • Multimeter (optional, for charger check)
  • Screwdriver (for battery compartment)
Step 1 of 5

Quick triage — pick your path

Quick triage — pick your path

Choose the option that matches what you see. You can jump straight to that section.

Show full guide

Steps

Goal: Confirm the battery is dead, check connections, then replace the battery.

  • Confirm the panel or UPS shows a battery fault. Unplug from AC—a dead battery will not power the load.
  • Good: Battery fault. Proceed to Check connections.
  • Bad: No fault—different problem. See When to get help.

Check connections

Goal: Rule out loose or corroded sealed lead-acid connections.

  • Turn off power. Open the battery compartment. Check leads at the battery and panel.
  • Tighten loose connections. Clean corrosion. Restore power. Allow charge time.
  • Good: Connections secure. If fault persists, replace the battery.
  • Bad: Loose or corroded—fix and retest.

Replace battery

Goal: Replace the battery with a compatible sealed lead-acid model.

  • Turn off power. Disconnect the old battery (negative first, then positive).
  • Connect the new battery (positive first, then negative). Restore power.
  • Allow 4–8 hours to charge. If the fault persists after 24 hours, the charger may need service—call a pro.

When to get help

  • Call your alarm company or a technician if the new battery still will not charge.
  • Do not open the panel if you are not comfortable with wiring.

Verification

  • The battery fault clears after replacement and charge time.
  • The unit runs on battery when AC power is removed.
  • No battery fault on the display.

Escalation ladder

Work from the device outward. Stop when the problem is fixed.

  1. Confirm dead Verify the panel or UPS shows battery fault.
  2. Check connections Check battery leads and charger output.
  3. Replace battery Replace with a compatible model.
  4. Allow charge time Leave on AC for 4–8 hours.
  5. Call a pro Alarm company or technician if new battery will not charge.

What to capture if you need help

Before calling support or posting for help, have these ready. It speeds everything up.

  • Battery voltage and capacity
  • Whether connections were checked
  • Steps already tried

Does the panel or UPS show a battery fault?

Check the display for Low Battery, Battery Fault, or Replace Battery.

Check the display. Unplug from AC—a dead battery will not power the load. Good: battery fault or unit powers off when unplugged. Bad: no fault—different problem.

Yes No

You can change your answer later.

Are battery connections secure?

Check leads at the battery and panel.

Turn off power. Open the battery compartment. Check sealed lead-acid connections. Clean corrosion. Good: connections secure. Bad: loose or corroded—fix and retest.

Yes No

You can change your answer later.

Fix connections

Tighten leads. Clean corrosion. Restore power. Allow charge time. Retest.

Done

Replace the battery

Replace with a compatible sealed lead-acid or per manual. Turn off power. Disconnect old, connect new. Restore power. Allow 4–8 hours to charge. If fault persists, the charger may need service—call a pro.

Done

Call a pro

Call your alarm company or a technician if the new battery still will not charge. The charger or panel may need service.

Done

Reviewed by Blackbox Atlas

Frequently asked questions

Why would a backup battery die?
Backup batteries typically last 3–5 years. Age, heat, and repeated deep discharges shorten life. A dead battery will not hold a charge and the panel or UPS will show a fault.
Can I replace the backup battery myself?
Yes, for most security panels and UPS units. Turn off power, disconnect the old battery, connect the new one (match polarity), and restore power. Check your manual for the correct battery type.
When should I call a pro for a backup battery?
Call if you have replaced the battery with a compatible model and it still will not charge. The charger or panel may need service. Do not open the panel if you are not comfortable with wiring.

Rate this guide

Was this helpful?

Continue to