TCL P331M Replacement Battery 3.7V 1800mAh TLi019CA

TCL P331M — 3.7V Li-ion Replacement Battery (TLi019CA)

This is a 3.7V Li-ion cell rated at 1800mAh (6.66Wh), built to the TLi019CA specification for the TCL P331M smartphone. It replaces the original cell when capacity has dropped and the phone can no longer hold a usable charge through a normal day. Voltage, connector type, and physical dimensions match the P331M battery bay directly.

• P331M cell fitment: The P331M uses a single-cell 3.7V Li-ion pack with a compact form factor — 67.55 x 52.08 x 4.60mm. The BMS on this phone communicates with the charge IC over a single NTC thermistor line. Any cell outside the correct impedance range will trigger a charge fault within the first cycle.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the P331M platform. The BMS accepted the cell without fault codes, and the charge IC reached full termination voltage without interruption.
• Fuel gauge recalibration on first use: After installation, run one complete discharge down to auto-shutdown, then charge fully to 100% without interruption. This gives the coulomb counter a full reference sweep against the new cell curve — skip this step and the percentage readout will drift by 10–20% for the first several cycles.

Why the P331M reports wrong battery percentage after a cell swap

The P331M uses a fuel gauge IC that tracks charge state by counting coulombs relative to a stored discharge curve from the original cell. A new cell has different internal impedance and a slightly different voltage profile across its discharge range. Until the IC maps a full cycle on the new cell, it reads percentage off the old reference curve and reports figures that are 10–20% higher or lower than actual. One uninterrupted full discharge followed by a full charge corrects the stored curve.

Sudden shutdown at 20–30% on the replacement cell

This happens when the modem or display pulls a current spike that drops cell voltage below the BMS cutoff threshold — even though the fuel gauge still shows charge remaining. On a new cell that hasn't been calibrated, the gauge overestimates remaining capacity and the phone hits the voltage cliff without warning. The fix is the same full discharge-recharge cycle: once the fuel gauge IC has a real discharge curve, it begins reporting the low-voltage knee accurately and triggers the OS shutdown warning at the right percentage. If shutdowns continue past three full cycles, check that the replacement cell voltage reads at least 3.6V at rest before installation.