KAZAM Trooper 450L Replacement Battery TR4L50 3.7V 2000mAh

KAZAM Trooper 450L — 3.7V Li-ion Replacement Battery (TR4L50)

This is a 3.7V Li-ion replacement battery for the KAZAM Trooper 450L and Trooper 450L Dual SIM smartphones. It carries a 2000mAh (7.4Wh) capacity, matching the original cell specification. When the factory battery degrades and can no longer hold a useful charge, this cell restores the phone to normal function without a full device replacement.

• Trooper 450L and Dual SIM coverage: Both variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell fits either configuration. No modification is needed between the standard and Dual SIM board.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Trooper 450L platform. The BMS accepted the cell without error flags, and the charge IC completed a full constant-current to constant-voltage taper without interruption.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle manually. This lets the fuel gauge IC map the new cell's discharge curve before Android's battery stats layer starts reporting percentage to the screen.

Why the Trooper 450L reports wrong battery percentage after a cell swap

The Trooper 450L uses a fuel gauge IC that builds its state-of-charge model from learned discharge curves over multiple cycles. When you swap in a new cell, that learned model still references the old, degraded cell's voltage-to-capacity mapping. The result is percentage readings that jump or stall — the IC is reporting against a curve that no longer matches the physical cell. One full uninterrupted discharge followed by a full charge resets the coulomb counter and lets the IC anchor to the new cell's actual voltage profile. After that single cycle, percentage accuracy stabilises.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or screen draws a current spike that the cell cannot sustain at low state-of-charge, causing terminal voltage to drop below the BMS cutoff threshold — even though the reported percentage suggests charge remains. The fuel gauge IC hasn't yet learned the new cell's voltage cliff, so it doesn't warn the OS before the shutdown hits. Run two full discharge-charge cycles without background-heavy apps to let the IC anchor the cutoff point accurately. If shutdowns persist past two cycles, check that terminal voltage reads at least 3.6V at what the phone displays as 20%.