Lenovo S898ts Replacement Battery BL212 3.7V 2050mAh

Lenovo S898ts / A620T Series — 3.7V Li-ion Replacement Battery (BL212)

This is a 3.7V, 2050mAh Li-ion replacement battery for the Lenovo S898ts, A708T, A628T, and A620T smartphones. It replaces OEM part numbers BL212 and BL225. Fit this cell when the original no longer holds a usable charge through a normal day of calls, data, and screen time.

• S898ts and A620T series compatibility: These models share the same battery bay dimensions, connector pinout, and BMS communication protocol. The 73.65 × 63.75 × 3.80mm cell fits the tray without modification, and the BMS handshake passes the charge IC negotiation on first boot.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the S898ts platform. The BMS held the 4.2V charge ceiling correctly and the protection circuit tripped at the expected low-voltage cutoff — no thermal events, no false shutdowns under screen and modem load.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC starts pushing higher current into an uncalibrated cell.

Why the S898ts reports wrong battery percentage after a cell swap

The fuel gauge IC stores a learned discharge curve from the old cell. A new cell has a different internal resistance profile, so the IC's coulomb counter starts reading against the wrong baseline. The phone may show 80% when the cell is actually at 60%, or vice versa. One full discharge — screen on, no charger — followed by a full charge resets the learned curve and brings the percentage readout back into line.

Sudden shutdown at 20–30% on the replacement cell

This happens when the fuel gauge IC hasn't yet recalibrated and the cell hits its real voltage floor before the OS thinks it's close to empty. Under modem transmit or screen brightness spikes, cell voltage drops sharply and the BMS protection circuit cuts power before the OS can trigger a soft shutdown. It is not a defective cell — it is an uncalibrated gauge. Run two full discharge-charge cycles without fast charging and the shutdowns will stop once the coulomb counter tracks the actual capacity of the new cell. After the second cycle, confirm the phone reaches a stable 4.20V at full charge before re-enabling fast charging.