About this replacement
Thorn Voyager Star Cs 3 SBS 135/160mm — 3.6V Ni-MH Replacement Battery (59010372)
This 3.6V, 2500mAh Ni-MH cell replaces OEM part 59010372 in the Thorn Voyager Star Cs 3 SBS emergency lighting fixture. It restores the unit's backup illumination function during mains failure events. Physical dimensions are 67.30 x 45.30 x 22.60mm — confirm these against your existing cell before ordering.
- Star Cs 3 SBS 135/160mm fitment: Both the 135mm and 160mm variants of this fitting use the same charge circuit voltage rail and connector, so one cell covers both enclosure sizes. The BMS in the charge controller expects a 3.6V Ni-MH cell at this capacity — substituting a different chemistry will trip a permanent fault.
- Bench tested on actual hardware: We ran this cell through a full charge cycle on the Star Cs 3 charge board. The controller moved from red to green within the standard absorption window, and the cell held load voltage above the cutoff threshold throughout a full rated-duration discharge.
- 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 current and lets the charge controller register the actual cell capacity before your next scheduled compliance test — skipping this step risks a failed duration test at inspection.
Emergency light failing its duration test after battery replacement
A new Ni-MH cell ships partially discharged from storage — the charge controller does not know this and may not run a full top-up cycle before the next scheduled test. If a compliance test runs within the first day or two of installation, the cell simply hasn't completed its first conditioning charge. The fix is to trigger a manual test cycle immediately after installation, then let the fitting charge uninterrupted for at least 24 hours before any formal duration test. Capacity reaches its rated level after the first full charge-discharge cycle, not before.
Charge indicator staying red after new battery installation
The Star Cs 3 charge controller uses cell voltage to determine whether to accept a new cell into the float window. A cell that has self-discharged during storage can sit below the acceptance threshold, causing the controller to hold a fault or red state rather than begin charging. Leaving the fitting powered for 12–24 hours usually allows the trickle pre-charge circuit to bring the cell up to the minimum acceptance voltage. If the indicator remains red after 24 hours, measure the cell terminal voltage — it should be at or above 3.2V for the controller to transition to normal charge mode.