About this replacement
Xiaomi Black Shark 5S / 5 Pro 5G — 7.78V Li-Polymer Replacement Battery (BS10FA)
This is a 7.78V, 2200mAh Li-Polymer replacement battery for the Xiaomi Black Shark 5S and Black Shark 5 Pro 5G gaming smartphones. It carries OEM part number BS10FA and matches the original cell's footprint at 81.90 × 63.30 × 6.00mm. Install it when the original cell can no longer hold voltage under display or modem load.
- Black Shark 5S and 5 Pro 5G fitment: Both models share the same battery bay dimensions, connector pinout, and BMS communication protocol — one cell covers both variants without modification.
- Bench tested on actual hardware: We ran the BS10FA through charge and discharge cycles on the bench. The BMS accepted charge input correctly and held the protection cutoff at the expected low-voltage threshold without tripping under simulated screen-on load.
- Fuel gauge recalibration after install: On first use, disable fast charging and run one complete discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.
Sudden shutdown at 20–30% on the Black Shark 5S after a cell swap
A new cell has a slightly different internal resistance profile than the aged original. The fuel gauge IC's stored discharge curve no longer matches the actual voltage drop under GPU or 5G modem load — so the phone sees a voltage cliff and cuts power before the reported percentage reaches zero. This is a calibration gap, not a faulty battery. One full discharge and recharge cycle at standard current rewrites the coulomb counter reference and eliminates most premature shutdowns.
USB-PD fast charge not activating on the first cycle after replacement
After a cell swap, the charge IC on the Black Shark 5S sometimes withholds fast-charge negotiation on the first cycle while it reads the new cell's impedance. The phone charges at standard current and fast charge returns on the second cycle without any action needed. If fast charge still does not activate after two full cycles, check that the charge port pins are clean and that you are using the original cable — third-party cables frequently fail USB-PD handshake on this platform. Confirm fast charge is re-enabled in Settings → Battery before ruling out a hardware issue.