Streamlight PolyStinger LED HAZ-LO 4.8V Replacement Battery

Streamlight PolyStinger LED HAZ-LO — 4.8V Ni-MH Replacement Battery (76375)

This is a 4.8V, 3000mAh Ni-MH battery pack for the Streamlight PolyStinger LED HAZ-LO flashlight (Part No. 76375). It fits the intrinsically safe version of the PolyStinger platform — the one cleared for use in potentially explosive atmospheres. Voltage and cell count match the original pack exactly.

• PolyStinger LED HAZ-LO platform fit: The HAZ-LO variant uses the same 4.8V four-cell sub-C Ni-MH configuration as the standard PolyStinger, but the housing and charge contacts are built to intrinsic safety ratings. This pack replicates that configuration — cell count, voltage rail, and connector orientation all match the original.
• Bench tested on actual hardware: We ran this pack through the PolyStinger LED HAZ-LO charge cycle using the standard Streamlight dual-bank charger. The pack accepted a full charge without thermal runaway and held voltage above 4.6V through the bulk of the discharge curve.
• Sub-C cell replacement protocol: The PolyStinger LED HAZ-LO draws high current on full output. If your original pack has one weak cell from partial charging cycles, the HAZ-LO driver will brownout early — the whole pack needs replacing, not just topping off with a charger.

PolyStinger LED HAZ-LO dimming before the battery indicator drops

The HAZ-LO driver has brownout protection that steps output down before the battery indicator registers low. At high output, the four-cell Ni-MH pack voltage sags under load — the driver reads that sag as a low-voltage condition and cuts lumens to protect the LED and circuit. The indicator measures resting voltage, not load voltage, so it lags behind what the driver actually sees. If you notice dimming in full output mode, the pack is near end of charge even if the indicator hasn't lit yet.

Flashlight cycling through modes on its own near end of charge

Mode-cycling near end of charge is a driver brownout loop — the pack can't sustain the voltage needed to hold the current mode, the driver drops to a lower mode, voltage briefly recovers, and the driver tries to step back up again. This repeats until voltage collapses below the cutoff threshold. It is not a fault with the switch or driver board. Switch manually to a lower output mode when this starts — the pack has enough charge left to run at reduced output. When voltage at the contacts reads below 4.2V under load, recharge.