Schrack NLAKKU3215 Emergency Light Replacement Battery 3.2V 1500mAh

Schrack A3U383AT2.V2-S Series — 3.2V LiFePO4 Replacement Battery (NLAKKU3215)

This is a 3.2V LiFePO4 cell rated at 1500mAh (4.8Wh), supplied as a direct replacement for Schrack emergency lighting units using OEM part number NLAKKU3215. It fits the A3U383AT2.V2-S, A3U383AT2.V2-W, A3U383ENB-S, A3U383ENB-W, and over 43 additional Schrack emergency exit and backup lighting models. The cell dimensions are 68.80 × 18.50 × 18.50mm — measure your existing cell before ordering if you are unsure which variant your fitting holds.

• A3U383 and ENB platform compatibility: These Schrack fittings share the same 3.2V single-cell architecture and NLAKKU3215 connector format. The charge controller in each unit expects a LiFePO4 float voltage of approximately 3.4–3.6V — swapping in a different chemistry will cause incorrect charge termination and false fault signals.
• Bench tested on actual hardware: We ran this cell through charge acceptance, float hold, and load discharge on a Schrack emergency lighting fixture. The BMS accepted the cell without fault codes, float voltage stabilised within the controller's acceptance window, and the cell held load current through the full test duration.
• First-cycle test requirement: Perform a manual test cycle within 24 hours of installation by holding the test button for the full rated duration. This confirms the new cell accepts load and allows the charge controller to register the replacement cell's capacity before the next scheduled compliance test.

Charge indicator staying red after new battery installation

LiFePO4 cells lose voltage during storage — a new cell can sit at 2.9–3.1V when it leaves the warehouse. Schrack charge controllers use a float acceptance window, and a cell below roughly 3.0V at rest may be seen as outside that window, keeping the fault LED active. The controller needs 30–60 minutes of trickle input before it recognises the cell as chargeable and transitions to normal charge mode. If the red indicator persists beyond two hours with mains connected, check the cell terminal voltage directly — it should be climbing toward 3.2V; if it is not moving, verify the connector seating before assuming the cell is faulty.

Emergency light dims and drops out partway through a duration test

This usually happens on the first or second test cycle after replacement, not because the cell is defective, but because it has not yet completed a full charge–discharge conditioning cycle. A cell installed and tested within a few hours of connection has not reached its rated capacity — the charge controller has not had time to top-balance the cell to full charge. Leave the fitting connected to mains for a full 24-hour charge before running the duration test. After one complete cycle, rated capacity is available and the light should hold load for the full test period.