About this replacement
KAZAM Trooper 445L — 3.7V Li-ion Replacement Battery (TR4L45)
This is a 3.7V, 1500mAh Li-ion cell built to the TR4L45 specification for the KAZAM Trooper 445L smartphone. It replaces the original battery when the cell has degraded, stopped holding charge, or failed to power the device. Voltage, connector, and physical footprint (67.50 × 51.94 × 4.65mm) match the factory specification.
- Trooper 445L fit: The 445L uses a fixed 3.7V single-cell architecture with a proprietary connector keyed to the TR4L45 form factor. Voltage rail, connector pinout, and BMS communication protocol are consistent across this model line — no adapter or modification required.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Trooper 445L platform. The BMS handshake completed correctly on first connection, charge acceptance registered immediately, and thermal behaviour across the charge curve stayed within normal bounds.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the charge controller begins applying higher current on subsequent cycles.
Sudden shutdown at 20–30% on the Trooper 445L after a cell swap
This happens because the fuel gauge IC on the Trooper 445L is still calibrated to the old cell's discharge curve. A new cell with a slightly different voltage-to-capacity profile hits the voltage cliff earlier than the gauge expects, triggering a protective shutdown before the reported percentage reaches zero. The modem radio and screen together draw enough current to cause a rapid voltage drop under load, even when the gauge shows charge remaining. One full discharge-charge cycle at standard rate — without fast charge — lets the coulomb counter recalibrate against the new cell and eliminates premature shutdowns.
Phone won't power on after the replacement battery sat in storage
Li-ion cells self-discharge in storage, and if the TR4L45 cell dropped below approximately 2.5V, the BMS enters a lockout state to prevent damage from deep discharge. The Trooper 445L will show no response to the power button in this state. Connect the phone to a wall charger — not a PC USB port — and leave it for 15–20 minutes without pressing anything. The charge IC will trickle current into the cell until voltage climbs above the BMS re-enable threshold, at which point the device will begin a normal charge cycle.