Leagoo Elite 5 BT-557P Compatible Battery 3.8V 3800mAh

Leagoo Elite 5 — 3.8V Li-ion Replacement Battery (BT-557P)

This is a 3.8V Li-ion cell rated at 3800mAh (14.44Wh), built to the BT-557P specification for the Leagoo Elite 5 smartphone. It replaces the original battery when the cell has degraded, lost capacity, or stopped holding a charge. Voltage and connector match the Elite 5 board directly.

• Elite 5 fit: The Elite 5 uses a sealed back panel with a specific connector orientation and BMS handshake tied to the BT-557P cell profile. Using a mismatched cell can trigger immediate charge rejection at the PMIC level, regardless of voltage match.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence on the Elite 5 board and confirmed the BMS accepted the cell, the charge IC reached termination voltage correctly, and the protection circuit tripped at the expected overcurrent threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC pushes high current into an uncalibrated cell — preventing erratic percentage readings from the first charge onward.

Why the Elite 5 reports wrong battery percentage after a cell swap

The Elite 5 uses a coulomb counter-based fuel gauge IC that builds its capacity model against the original cell's discharge curve. When you install a new cell, the IC still references that old curve, so the displayed percentage drifts from actual state of charge. This usually appears as the phone jumping from 40% to 5% without warning, or showing 100% for an unusually long stretch. One full discharge-charge cycle without fast charging resets the IC's learned curve to the new cell and corrects the reported percentage within two to three cycles.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff failure, not a capacity issue. Under combined modem, screen, and processor load, the cell voltage drops faster than the fuel gauge IC predicted — falling below the PMIC's cutoff threshold while the display still reads 20–30%. The root cause is an uncalibrated fuel gauge reading a new cell curve as if it were the old degraded one. Let the phone discharge fully to auto-shutdown, then charge uninterrupted to 100% — this single cycle gives the IC enough data to recalculate the cliff point accurately. After two full cycles, shutdowns below 15% should stop.