About this replacement
IRON LUX E73 417 12 / AT 26m — 6.4V LiFePO4 Replacement Battery (A-922/HT)
This is a 6.4V 600mAh LiFePO4 cell built to the A-922/HT specification. It fits the IRON LUX E73 417 12 and AT 26m emergency lighting units — the type mounted above fire exits and escape routes in commercial and industrial buildings. Capacity is 600mAh (3.84Wh), matching the original cell exactly.
- E73 417 12 and AT 26m platform: Both fittings run a 6.4V LiFePO4 chemistry rail with the same physical footprint and connector orientation. The A-922/HT cell meets the voltage and form factor the charge controller in each fitting expects.
- Bench tested on actual hardware: We cycled this cell through mains-present charging and a simulated mains-fail discharge event. The BMS held voltage within tolerance across the full discharge arc and the charge controller accepted the cell without a fault flag.
- First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated test duration. This lets the charge controller register the new cell and confirms load acceptance before your next scheduled compliance inspection.
Emergency light failing its duration test after battery replacement
A freshly installed LiFePO4 cell coming out of storage may not be at full charge capacity on day one. The charge controller in the E73 417 12 applies a float charge — not a fast charge — so the cell can take up to 24 hours to reach rated capacity. Running a duration test before that window closes will produce a short result that does not reflect the cell's actual capacity. Allow a full 24-hour charge period after installation, then run the test. If the fitting still fails after 24 hours on mains power, check float charge voltage at the cell terminals — it should read between 7.2V and 7.3V under no load.
Charge indicator staying red after new battery installation
Some IRON LUX fittings latch a fault LED in hardware and will not clear it automatically after a battery swap. Even when the new cell is correctly seated and charging, the red indicator stays on until the fault flag is manually reset. On the E73 417 12, hold the test button for three seconds with mains power present — this triggers a reset cycle on the charge controller. If the indicator does not switch to green within two minutes of the reset, check the cell connector seating and confirm terminal voltage is above 6.0V.