About this replacement
Fullham FHSAC1-UNV-40L — 6.4V LiFePO4 Replacement Battery (FHSBATL2-3.2)
This is a 6.4V 3000mAh (19.2Wh) LiFePO4 replacement battery for the Fullham FHSAC1-UNV-40L emergency lighting fixture. It restores backup power capability when the original cell can no longer hold charge during mains failure events. Matches OEM part numbers FHSBATL2-3.2 and GF6X4XXXX03.
- FHSAC1-UNV-40L fixture fit: The FHSAC1-UNV-40L uses a dedicated LiFePO4 cell at 6.4V nominal — not a standard NiCd or NiMH pack. The charge controller inside the fitting floats at a voltage window specific to LiFePO4 chemistry, so swapping to any other chemistry will either undercharge or damage the cell through the controller's fixed charge curve.
- Bench tested on actual hardware: We ran this cell through a full mains-interrupt cycle on the FHSAC1-UNV-40L fixture. The BMS accepted the cell without fault LEDs, the charge controller moved to float within the expected window, and the fitting activated cleanly on simulated mains loss.
- First-cycle activation after installation: Within 24 hours of fitting this battery, hold the test button for the full rated duration. This forces the charge controller to register the new cell's actual capacity and clears any residual fault state carried over from the depleted original cell before your next scheduled compliance inspection.
Charge indicator staying red after fitting the new cell
LiFePO4 cells lose voltage during storage. If this battery sat in a warehouse for several months, its resting voltage may sit below the float acceptance threshold the FHSAC1-UNV-40L charge controller expects at the start of a charge cycle. The controller reads that low voltage as a fault condition rather than a depleted cell, so it holds the red LED instead of transitioning to amber or green. Leave the fitting on mains power for a full 24-hour conditioning period — the controller will gradually bring the cell voltage up into the acceptance window and then switch to normal float charge. If the LED is still red after 24 hours, check the connector seating before assuming a fault with the fitting itself.
Emergency light dims partway through the duration test
A new cell that has not yet completed one full charge cycle will not deliver its rated 3000mAh on first discharge. The fitting draws its full LED load from the moment mains power is cut, and an undercharged cell hits its lower voltage cutoff before the test duration completes — causing the light to dim or cut out. This is not a fault with the cell. Run the fitting on mains charge for at least 24 hours before conducting any duration test. After one complete charge-discharge cycle, the cell stabilises at its rated capacity and the fitting will hold output for the full test period.