About this replacement
Xiaomi Black Shark 3 / 3S Series — 3.85V Li-Polymer Replacement Battery (BS06FA)
This is a 3.85V, 2300mAh Li-Polymer replacement cell carrying OEM part number BS06FA. It fits the Black Shark 3, Black Shark 3S, Black Shark 3S 5G, and KLE-H0 variants. It slots into the same battery bay as the factory cell and connects to the same BMS contacts.
- Black Shark 3 and 3S platform compatibility: All listed models share the same physical battery bay, connector pinout, and BMS handshake protocol. The BS06FA OEM part number covers the full production run of this platform, so there is no connector mismatch between 3 and 3S variants.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a Black Shark 3 unit. The BMS accepted the cell without fault codes, fast-charge handshake completed on the second cycle, and voltage held stable under sustained GPU load.
- Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% on standard 5V charging. This lets the fuel gauge IC map the new cell's discharge curve before the coulomb counter locks in its reference points.
Sudden shutdown at 20–30% on the Black Shark 3 after a cell swap
A new Li-Polymer cell has a slightly different voltage-to-capacity curve than the aged cell the fuel gauge IC originally calibrated against. Under high GPU or modem load, the phone draws enough current to pull the cell voltage below the shutdown threshold faster than the gauge predicts. The gauge still shows 20–30% remaining, but the actual open-circuit voltage has already collapsed. One full uninterrupted discharge-charge cycle resets the coulomb counter and aligns the IC to the new cell's curve, eliminating the early cutoff.
USB-PD fast charge not triggering after replacement
On the first charge cycle, the charge IC on the Black Shark 3 runs an impedance check against the new cell. A fresh high-impedance cell can cause the IC to fall back to standard 5V charging as a precaution. This is not a fault — it resolves after the first full cycle once the BMS has logged baseline cell data. If fast charge still does not trigger after two full cycles, check that the charger output voltage is at least 9V and the cable supports the current rating required by Xiaomi's proprietary fast-charge protocol.