About this replacement
Sharp Waterproof 935SH Series — 3.7V Li-ion Replacement Battery (SHBCC1)
This is a 3.7V, 700mAh Li-ion replacement battery for the Sharp Waterproof 935SH and related models including the 936SH, 934SH, and 933SH. It replaces OEM part numbers SHBCC1, XN-1BT22, and XN-1BT21. Swap it in when the original cell no longer holds a usable charge or causes unexpected shutdowns.
- 935SH series compatibility: The 933SH through 936SH share the same battery bay dimensions, connector pinout, and BMS handshake protocol — all accept the SHBCC1 cell footprint at 3.7V nominal without modification.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the 935SH platform and confirmed the BMS accepted the cell without fault codes, thermal events, or charge-current limiting at the expected cutoff points.
- Fuel gauge recalibration on first use: On first installation, disable fast charging and run one full discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the charge controller applies high-current inputs to an uncalibrated cell.
Sudden shutdown at 20–30% on the Sharp 935SH after a cell swap
The 935SH fuel gauge IC retains the discharge curve of the previous cell in its coulomb counter. When a new cell is installed, the IC may trigger a low-voltage shutdown earlier than expected because it is comparing current cell voltage against an old reference curve. This is not a fault in the replacement cell — it is the gauge reading a mismatch between expected and actual cell impedance. One full discharge down to automatic cutoff followed by a complete charge cycle resets the reference and resolves the early shutdown behaviour.
OS percentage jumping erratically after installation
Erratic percentage readings — jumping from 45% to 12% or spiking upward mid-use — point to the fuel gauge IC recalibrating against the new cell's voltage-to-capacity curve. The coulomb counter has not yet built an accurate state-of-charge model for the replacement cell. Do not interrupt the first charge cycle. Let the phone charge to 100%, confirm it shows the full-charge indicator, then discharge naturally to cutoff. After that single uninterrupted cycle, percentage reporting stabilises.