Fullham FHSBATT3-C3 Compatible Battery 3.6V 3000mAh Ni-CD

Fullham FHSBATT3-C3 — 3.6V Ni-CD Replacement Battery

This is a 3.6V 3000mAh nickel-cadmium replacement cell for the Fullham FHSBATT3-C3 emergency lighting unit. It fits emergency exit signs and backup lighting systems used in commercial and industrial facilities. Capacity is 3000mAh (10.8Wh), matching the original cell specification.

• FHSBATT3-C3 platform fit: The FHSBATT3-C3 charge controller runs a constant trickle current sized for Ni-CD chemistry. Substituting a different chemistry breaks the charge curve — this cell matches the voltage profile and internal resistance the controller expects.
• Bench tested on actual hardware: We cycled this cell through a full charge and load test on the FHSBATT3-C3 platform. The charge controller accepted the cell without fault, and the BMS logged a clean float transition at end-of-charge.
• First-cycle conditioning on this fitting: Within 24 hours of installation, hold the test button for the full rated duration. This forces a complete discharge-to-load cycle, which allows the charge controller to register the new cell's capacity before it logs any compliance test result.

Charge indicator staying red after new cell installation

A fresh Ni-CD cell from storage typically sits at a resting voltage below the float acceptance window the FHSBATT3-C3 controller uses to confirm a healthy pack. Until the cell voltage rises past that threshold through initial trickle charging, the controller holds the fault or charging indicator red. Leave the unit on mains power for at least 24 hours after installation. If the indicator has not shifted to green by 48 hours, measure the cell voltage at the connector — it should read above 3.3V to confirm current is flowing.

Emergency light dims partway through a duration test

A cell that has not completed its first conditioning cycle will show full brightness initially, then drop off under sustained load — this is not a faulty cell. Ni-CD cells need one full charge-discharge cycle before the active material in the plates is fully formed and delivering rated capacity. Run the manual test cycle within 24 hours of installation to condition the cell before any scheduled compliance test. After conditioning, the cell should sustain rated output voltage above 3.0V throughout the full test duration.