Streamlight Strion 2020 Replacement Battery 3.7V 3400mAh

Streamlight Strion 2020 / Strion 2020 HC — 3.7V Li-ion Replacement Battery (74436)

This 3.7V, 3400mAh Li-ion battery replaces the original cell in the Streamlight Strion 2020 and Strion 2020 HC flashlights. Both models use the same OEM part number (74436) and share an identical battery bay and connector. Capacity is 3400mAh (12.58Wh), matching the factory specification.

• Strion 2020 and 2020 HC fit: Both variants run the same driver board and charging circuit. The 74436 battery uses a matching connector and BMS communication profile, so the charger recognises the cell and completes a full charge cycle without fault flags.
• Bench tested on actual hardware: We cycled this battery through the Strion 2020 charger and confirmed the BMS accepted the charge handshake cleanly. The driver stepped through all output modes without triggering thermal cutoff or low-voltage stepdown at full state of charge.
• Turbo mode draw management: The Strion 2020's turbo mode pulls significantly more current than standard or low modes. Avoid locking the light in turbo for extended periods when the cell is already below 50% — the driver's brownout protection will step output down before the indicator signals low.

Why the Strion 2020 steps down output before the battery indicator reads low

The Strion 2020's driver monitors cell voltage in real time and steps down output the moment voltage sags below its brownout threshold. At high output, current draw is heavy enough to cause a temporary voltage sag even when the cell still holds a reasonable charge. The indicator reads state of charge under low load, not under the load the driver actually sees during high-output use. Switching to a lower mode as soon as you notice dimming restores full output and gives the cell time to recover voltage above the cutoff threshold.

Strion 2020 cycling between brightness levels on its own near end of charge

When the cell voltage drops close to the driver's minimum threshold, the driver repeatedly attempts full output, triggers brownout protection, and steps down — creating a visible flicker or mode-cycling effect. This is not a driver fault or a defective battery; it is the protection circuit doing its job. The fix is to switch to a lower output mode immediately — the light will hold that mode stably because current draw drops well below the cutoff trigger. Recharge the cell before the next use; a cell that triggers this behaviour is below 3.0V under load.