AMOI AL-001 Replacement Battery 3.7V 750mAh Li-ion

AMOI AL-001 — 3.7V Li-ion Replacement Battery (AL-001)

This 3.7V, 750mAh Li-ion cell replaces the original battery in the AMOI AL-001 candybar mobile phone. It fits the AL-001 directly, restoring power to devices where the original cell no longer holds a usable charge. Capacity is 750mAh (2.78Wh), matching the stock specification.

• AL-001 platform fit: The AL-001 uses a slim 4.51mm cell with a specific contact layout. This replacement matches that footprint at 52.05 × 38.39 × 4.51mm, so the connector seats correctly and the battery door closes without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the AL-001 platform. The BMS accepted charge from the handset's onboard charge IC without tripping a fault, and protection thresholds fired correctly at the low-voltage cutoff.
• Fuel gauge recalibration on first cycle: After installing a new cell, run one full discharge down to automatic shutdown, then charge to 100% uninterrupted. The AL-001's fuel gauge IC needs that full sweep to map its coulomb counter to the new cell's actual discharge curve.

Why the AL-001 reports wrong battery percentage after a cell swap

The AL-001 uses a fuel gauge IC that stores a learned discharge curve from the previous cell. When you install a fresh 750mAh cell, the IC is still referencing the old degraded curve, so the percentage readout is inaccurate from the first boot. This mismatch causes the phone to show 50% while the actual cell voltage is much higher, or to report full charge before the cell has actually reached 4.2V. One complete discharge-to-shutdown followed by a full uninterrupted charge resets the coulomb counter and brings the percentage display in line with real cell state.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops below the modem's minimum operating threshold under transmission load, even though the fuel gauge still reads 20–30% remaining. On a fresh cell that hasn't been calibrated, the IC doesn't yet know where the voltage cliff sits on this specific cell's curve. The phone cuts out because the processor loses stable voltage, not because the battery is faulty. After one full calibration cycle, the fuel gauge maps that cliff correctly and begins warning at the right percentage — typically when cell voltage falls to around 3.5V under load.