About this replacement
ESYLUX Serie SLA / SLB / SLC / SLD — 3.2V LiFePO4 Replacement Battery (1579106)
This is a 3.2V, 1500mAh LiFePO4 cell for ESYLUX emergency lighting units across the Serie SLA, SLB Revision 2022, SLC, and SLD Revision 2022 ranges. It replaces OEM part numbers 1579106, 1579113, EN10032721, and EN10433054. If your fitting has failed a duration test or is showing a fault LED, this cell restores the internal power supply the unit draws on during mains failure.
- Serie SLA, SLB, SLC, SLD compatibility: These four ESYLUX fitting variants share the same 3.2V charge rail, the same physical cell bay (66.80 × 21.10 × 18.50mm), and the same charge controller logic. One cell part number covers all of them because the BMS handshake and float voltage are identical across the range.
- Bench tested on actual hardware: We cycled this cell through a full charge and load discharge on the ESYLUX charge circuit. The BMS accepted charge without tripping, held voltage above the low-battery cutoff threshold throughout the discharge phase, and the charge indicator advanced to green on completion.
- First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. A cell that has been in storage may sit slightly below the charge controller's float acceptance window — running one full test cycle lets the controller register the new cell and clears any residual fault state before your next compliance inspection.
Charge indicator staying red after new cell installation
ESYLUX SLA-series charge controllers use a float voltage window to confirm cell health before switching the LED green. A cell shipped from storage can arrive at 3.0V or slightly below — just outside the acceptance threshold. The controller reads this as a suspect cell and holds the fault state rather than beginning a normal charge cycle. Connecting the fitting to mains for 12–24 hours is usually enough for the controller to bring the cell up to float voltage (nominally 3.65V for LiFePO4) and clear the red indicator automatically.
Emergency light dims and cuts out partway through a duration test
This is different from a cell that won't charge at all. A cell that dims mid-test has accepted charge but hasn't yet been through a full conditioning cycle, so the charge controller has underestimated available capacity. On first activation from storage, internal resistance is slightly elevated and voltage sags under load faster than it will after one complete cycle. Run one full manual test immediately after installation — after a complete charge-discharge-recharge sequence, the controller recalibrates its capacity register and the fitting should hold output voltage for the full rated duration.