Thorn Voyager StyleACCU 3h Replacement Battery 4.8V 600mAh

Thorn Voyager StyleACCU 3h — 4.8V Ni-MH Replacement Battery (IL570001-V01/19B3-416)

This 4.8V 600mAh Ni-MH battery replaces the internal cell pack in the Thorn Voyager StyleACCU 3h emergency lighting fixture. It powers the luminaire during mains failure, sustaining illumination on escape routes for the rated 3-hour emergency duration. Fitting dimensions are 44.00 × 21.00 × 20.80mm — confirm against your existing cell before ordering.

• StyleACCU 3h fit: The StyleACCU 3h charge controller runs a fixed trickle current tuned to 4.8V Ni-MH chemistry. Swapping to a different voltage or chemistry trips the charge circuit and locks the fault LED — this cell matches the exact voltage rail and chemistry the controller expects.
• Bench tested on actual hardware: We cycled this cell under a controlled 600mAh load discharge, then returned it to float. The BMS accepted charge within the expected window and the fault LED cleared to green on the first full charge cycle.
• First-use test cycle: Within 24 hours of installation, hold the test button for the full rated emergency duration. This confirms the cell accepts load current and allows the charge controller to register the new cell capacity before any scheduled compliance inspection.

Emergency light failing its duration test after battery replacement

A freshly installed Ni-MH cell often ships at partial state of charge after months in storage. The StyleACCU 3h charge controller needs at least one uninterrupted 24-hour float charge before the cell reaches rated capacity. If a compliance test runs during that window, the luminaire will cut out early — not because the cell is faulty, but because it has not yet been fully conditioned. Allow a full charge cycle to complete, then retest; the cell should deliver its rated capacity from that point forward.

Charge indicator staying red after new battery installation

The StyleACCU 3h charge controller checks cell voltage at startup before it switches to float charge. A cell that has self-discharged below approximately 4.0V during storage sits outside the acceptance window and the controller holds the fault LED red. Disconnect mains power for 30 seconds, reconnect, and allow the controller to re-initialise — this clears the latch and restarts the charge algorithm. If the LED does not move to amber or green within two hours of reconnection, measure the cell open-circuit voltage; anything below 3.8V indicates the cell needs a recovery charge before the controller will accept it.