Nightstick 2168-BATT Replacement Battery 7.4V 3350mAh

Nightstick NSR-2168 — 7.4V Li-ion Replacement Battery (2168-BATT)

This is a 7.4V, 3350mAh Li-ion replacement battery for the Nightstick NSR-2168 rechargeable tactical flashlight. It replaces OEM part number 2168-BATT and fits the NSR-2168 directly. Voltage and cell count match the original so the flashlight driver runs at the correct operating range from the first charge.

• NSR-2168 compatibility: The NSR-2168 uses a two-cell Li-ion pack wired to a specific connector and BMS configuration. This replacement matches that cell layout, voltage rail, and connector pinout so the driver board receives the correct input without triggering a fault state.
• Bench tested on actual hardware: We ran this pack through charge, discharge, and turbo-mode draw cycles on the NSR-2168. The BMS held cutoff at the correct low-voltage threshold and did not trigger premature shutdown under high-current draw in turbo mode.
• Multi-cell replacement tip: The NSR-2168 pack uses two cells in series. If one cell in the original pack has degraded while the other is still healthy, do not attempt to replace a single cell — swap the full pack. Mismatched cell capacities cause one cell to hit the low-voltage cutoff before the other, which stresses the weaker cell on every discharge cycle.

Turbo mode output dropping faster than standard mode

Turbo mode on the NSR-2168 draws significantly more current than standard or low modes — often five to ten times higher. At that draw rate, the pack voltage drops faster, and the driver steps output down sooner to protect the cells. This is normal driver behaviour, not a fault with the battery. If turbo runtime feels short, run a full charge cycle to 8.4V before the next use and switch to high mode for extended output.

Flashlight brightness stepping down before the low-battery indicator triggers

The NSR-2168 driver uses brownout protection — it steps output down when pack voltage drops to a threshold slightly above the BMS hard cutoff. This means brightness visibly reduces before the indicator activates, which is intentional. The driver is protecting the cells from being pulled below the safe discharge floor. If this happens earlier than expected on a new pack, check that the battery was fully charged to 8.4V before first use. A partial first charge leaves less usable capacity in the cycle.