About this replacement
Ceag W270 / W276 Series — 4.8V Ni-MH Replacement Battery (40071345253)
This is a 4.8V, 10000mAh Ni-MH replacement battery for Ceag emergency lighting units. It fits the W270, W276, Handlampe SEB5.4L, SEB5.3, and several additional fixtures in the same family. Capacity is 48Wh — matching the original cell pack specification.
- W270 / W276 family compatibility: These fixtures share a common 4.8V cell configuration, connector pinout, and charge circuit. The BMS in each unit expects the same voltage curve and internal resistance range across the range, so one cell pack covers the whole group.
- Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle on the W270 charge circuit. The BMS accepted the pack without error flags, charge current tapered normally at peak capacity, and the LED driver received stable voltage throughout the discharge curve.
- First-cycle brightness calibration on W270 units: Run the light at medium brightness for the first full cycle. The LED driver in the W270 calibrates its current output against the new cell's resistance profile before maximum-brightness operation. Skipping this step can cause the driver to under-drive the LEDs on the first high-draw test.
Why the W270 dims before the low-battery indicator triggers
The W270 LED driver reduces current draw when cell voltage drops below a soft threshold — this happens before the BMS trips the low-battery warning. It is a deliberate protection step in Ceag's driver firmware, not a fault in the battery. The result is a visible dimming that can look like battery failure even though the pack still has usable charge. This is expected behaviour with both original and replacement Ni-MH cells at the 4.8V nominal level.
Light not reaching full brightness after fitting a new pack
A new Ni-MH cell ships at partial state of charge — typically 40–60% — and the W270 driver checks resting voltage before enabling maximum output. If resting voltage is below the driver's minimum input threshold, the unit operates at reduced brightness even though the pack is healthy. Fit the battery, place the unit back on its charger, and run a full charge before testing at maximum brightness. After one complete charge cycle the pack will sit above 5.4V resting and full output will engage normally.