About this replacement
Lenovo S920 — 3.8V Li-ion Replacement Battery (BL208)
This is a 3.8V, 2000mAh Li-ion replacement battery for the Lenovo S920 smartphone. It slots in where the original BL208 sits and restores power delivery to the display, modem, and application processor. Capacity matches the factory spec at 7.6Wh.
- S920 fit confirmation: The S920 uses a specific connector pinout and BMS handshake tied to the BL208 cell format. This replacement matches that pinout and the charge IC voltage thresholds the S920 expects — 4.35V charge ceiling, 3.0V low cutoff.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the S920 platform. The BMS accepted the charge handshake on the first cycle, held voltage above 3.6V under combined modem and display load, and tripped cutoff cleanly at the low-voltage threshold without false shutdowns.
- Fuel gauge recalibration on first use: After fitting this cell, disable any fast charge mode and run one full discharge down to automatic shutoff, then charge uninterrupted to 100%. This gives the S920 fuel gauge IC one clean reference cycle against the new cell's discharge curve before it starts reporting percentages.
Sudden shutdown at 20–30% on the S920 after a cell swap
The S920's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell with a different internal resistance profile hits a voltage cliff at a different state of charge than the old map expects. When modem transmit or screen brightness pulls current, the cell voltage dips below the shutdown threshold faster than the gauge predicts. Running one full discharge-to-shutoff cycle lets the coulomb counter reset its endpoint and eliminates most premature shutdowns.
Phone shows wrong battery percentage after replacement
The S920 stores learned battery parameters in the fuel gauge IC — those values are tied to the worn cell you removed, not this one. Until the IC relearns, percentage readouts can jump, stall, or read 20% higher than actual. Force a full recalibration: charge to 100% with the device off, then use normally until the phone shuts down on its own, then charge back to 100% without interruption. After that cycle, percentage tracking aligns to the new cell's actual discharge curve.