Thorn Voyager Solid E3D 3.6V 2500mAh Compatible Battery

Thorn Voyager Solid E3D — 3.6V Ni-MH Replacement Battery (59009287)

This is a 3.6V, 2500mAh Ni-MH replacement battery for the Thorn Voyager Solid E3D emergency lighting unit. It fits directly using OEM part number 59009287. The cell restores emergency illumination function during mains failure events in commercial and public-access environments.

• Solid E3D charge controller compatibility: The Solid E3D uses a trickle-charge controller matched to a specific cell voltage profile. This Ni-MH cell sits within that acceptance window, so the charge controller resumes float charging without tripping a fault state on installation.
• Bench tested on actual hardware: We cycled this cell through a simulated mains-failure discharge and confirmed the BMS accepted charge from rest voltage. Cell voltage stabilised at 4.2V post-charge and held under sustained load without dropout.
• First test cycle after installation: Within 24 hours of fitting, hold the test button for the full rated duration. This confirms the new cell accepts load and lets the charge controller register the cell before your next scheduled compliance test. Skipping this step risks a failed duration test on the compliance log.

Charge indicator staying red after new battery installation

A freshly shipped Ni-MH cell arrives in a partially discharged state — typically between 1.0V and 1.1V per cell. The Solid E3D charge controller has a minimum float-acceptance threshold. If resting voltage is below that window, the controller holds the fault LED red rather than transitioning to green. Leave the fitting on mains power for 12–24 hours. The controller will trickle the cell up through the acceptance threshold and shift to green once it reaches approximately 1.35V per cell under float.

Emergency light dims and cuts out partway through a duration test

This happens when a new cell has not completed a full conditioning cycle before the duration test is run. The cell delivers surface charge on the first activation but hits a voltage sag under sustained load before reaching rated capacity. It is not a faulty cell — it is an uncharged one. Run one full manual test cycle after 24 hours on charge, allow the fitting to return to full charge, then rerun the duration test. The cell should hold load voltage above 3.0V for the full rated period.