Bea-fon Classic Line C30 Replacement Battery 3.7V 1050mAh

Bea-fon Classic Line C30 — 3.7V Li-ion Replacement Battery (ICP4/38/57 1S1P)

This 3.7V Li-ion cell replaces the original battery in the Bea-fon Classic Line C30 mobile phone. It delivers 1050mAh (3.89Wh) capacity at the same voltage and physical footprint as the factory unit. Dimensions are 61.95 × 38.00 × 4.50mm — verify against your existing cell before fitting.

• Classic Line C30 fitment: The C30 uses a single-cell 1S1P configuration on a 3.7V rail. This cell matches that architecture — same connector orientation, same BMS contact layout, same physical envelope. No modifications needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a C30 unit. The BMS handshake completed correctly, charge termination triggered at the expected voltage, and the fuel gauge IC accepted the new cell without throwing a fault state.
• Fuel gauge recalibration on first use: After fitting, disable fast charging if your charger supports it and run one full discharge-to-charge cycle before normal use. This lets the fuel gauge IC map the new cell's discharge curve before it starts reporting percentages to the OS.

Sudden shutdown at 20–30% on the C30 after a cell swap

The C30's fuel gauge IC holds a discharge curve calibrated to the original cell. A new cell has a slightly different voltage-to-capacity curve, so the IC underestimates how close the cell is to its minimum voltage. Under brief high-current loads — a call connecting, the screen at full brightness — the cell voltage sags below the BMS cutoff threshold before the gauge shows low battery. One full discharge cycle, draining until the phone shuts itself off naturally, then a full charge, resets the coulomb counter to the new cell's actual curve. After that cycle, shutdowns at 20–30% stop.

Phone not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage. If this cell dropped below approximately 2.5V during transit or shelf time, the BMS may have entered a lockout state to prevent damage from deep discharge. The phone will show nothing — no charging animation, no response. Connect it to a wall charger, not a PC port, and leave it for 15–20 minutes without interruption. A wall charger supplies stable 5V at sufficient current for the charge IC to trickle the cell back above the BMS re-enable threshold, typically around 2.9V, after which normal charging resumes.