Peli M9 Flashlight Replacement Battery 3.6V 1800mAh

Peli M9 / Black Knight M9 — 3.6V Ni-MH Replacement Battery (75175)

This is a 3.6V, 1800mAh Ni-MH replacement battery for the Peli M9 and Black Knight M9 flashlights, as well as the 7050 and 7059 models. OEM part number 75175. It slots into the original battery compartment and works with the existing charging circuit in these torches.

• M9, Black Knight M9, 7050 and 7059 compatibility: All four models share the same cylindrical battery housing dimensions and the same 3.6V charging circuit. One cell format, one voltage rail — no connector or BMS differences across the group.
• Bench tested on actual hardware: We cycled this cell through the M9's onboard charging circuit and confirmed full charge acceptance, stable discharge voltage, and correct end-of-charge cutoff behaviour under the driver's regulation threshold.
• Single-cell replacement note: The M9 runs a single Ni-MH cell, so there is no multi-cell imbalance risk here. However, Ni-MH cells self-discharge faster than Li-ion. If the torch has been sitting unused for several months, run a full charge cycle before relying on it for critical use.

Why the M9 driver steps down output before the battery reads empty

Ni-MH cells have a relatively flat discharge curve, but voltage does drop noticeably as the cell nears depletion. The M9's driver circuit monitors this voltage and steps down output — reducing brightness — before the cell hits a hard cutoff. This is brownout protection, not a fault. The cell still has charge remaining when the step-down happens; it is protecting the driver from instability under a sagging voltage rail. If you notice the output drop, switching to a lower mode will extract the remaining capacity more efficiently.

Flashlight flickering or cycling through modes at the end of a charge

This is driver brownout cycling — the cell voltage is dropping below what the driver needs to hold a stable output, so it briefly cuts and restarts the circuit. You will see this as flickering or the torch jumping between modes without input. It is not a faulty battery or a faulty driver. Switch to a lower output mode immediately; the driver will stabilise and run the remaining charge down cleanly. If cycling starts early in a charge cycle rather than near the end, the cell has likely developed memory effect and needs several full charge-discharge cycles to recover capacity.