Streamlight Fire Vulcan LED 6.4V Replacement Battery 44610

Streamlight Fire Vulcan LED — 6.4V LiFePO4 Replacement Battery (44610)

This is a 6.4V 3200mAh LiFePO4 replacement battery for the Streamlight Fire Vulcan LED flashlight. It replaces OEM part 44610, the single rechargeable cell pack that powers the light's high-output LED driver. LiFePO4 chemistry holds voltage flat across the discharge curve, which matters in a high-draw flashlight where driver stability depends on a steady input rail.

• Fire Vulcan LED compatibility: The Fire Vulcan LED uses a dedicated single-pack configuration with a specific connector and BMS handshake tuned to LiFePO4 voltage thresholds. This replacement matches that 6.4V nominal and the cell footprint — 68.80 × 53.35 × 26.90mm — so it seats correctly in the battery compartment without modification.
• Bench tested on actual hardware: We ran this pack through charge and full-draw discharge cycles on the Fire Vulcan LED. The BMS held cutoff at the correct low-voltage threshold and did not trigger premature protection trips under sustained high-output draw.
• LiFePO4 storage voltage: LiFePO4 cells stored fully charged for extended periods can degrade faster than those stored at mid-charge. If the light is going into standby rotation, discharge it to roughly 50% before storing — around 3.2V per cell equivalent on this 6.4V pack.

Why the Fire Vulcan LED steps down output before the battery indicator reads low

LiFePO4 cells have a very flat discharge curve — voltage stays near nominal until the cell is close to depleted, then drops sharply. The Fire Vulcan's driver monitors input voltage and steps down output when it detects that drop, cutting brightness before the indicator catches up. This is the driver's brownout protection working correctly, not a battery fault. When you see output drop unexpectedly, the pack is near end of charge — swap it rather than continuing at reduced output.

Flashlight cycling through modes or flickering at end of charge

Mode cycling near end of charge happens when the driver's minimum operating voltage and the BMS low-voltage cutoff are close together. As the cell sags under load, the driver loses stable input, resets, and re-initiates — producing the flash-cycle behaviour. This is not a defective battery or driver. Switch to the lowest output mode immediately: it reduces current draw, raises effective cell voltage under load, and stops the cycling. If it continues at low mode, the pack needs recharging.