Sharp SH901iS Replacement Battery 3.7V 720mAh SHBQ01

Sharp SH901iS / SH902i Series — 3.7V Li-ion Replacement Battery (SHBQ01)

This is a 3.7V, 720mAh Li-ion cell carrying OEM part number SHBQ01. It fits the Sharp SH901iS, SH05, SH902i, and V401SH mobile phones. Swap it in when the original cell no longer holds enough charge for normal daily use.

• SH901iS, SH05, SH902i, and V401SH fit explained: These four models share the same battery bay dimensions, connector pinout, and BMS communication protocol. The SHBQ01 part number covers all four — no adapter or modification needed.
• Bench tested on actual hardware: We ran this cell through charge and discharge on the SH901iS platform. The BMS negotiated correctly, charge termination triggered at the right voltage, and no overcurrent flags were logged during the discharge cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable any fast-charge feature and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map its reference curve to the new cell before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement cell

Early-generation Sharp phones use a simple coulomb-counter fuel gauge that was calibrated against the original cell's discharge curve. When a new cell with a slightly different internal resistance profile is installed, the reported percentage diverges from the actual cell voltage. The phone reads 25% but the cell voltage has already dropped below the modem's minimum operating threshold under load — the radio or screen draws current, voltage sags, and the phone cuts off. One full discharge to automatic shutdown followed by a full charge resets the counter and corrects the percentage mapping.

Phone stays dark and will not respond after storage with a flat battery

If the phone was left discharged in storage, the cell can fall below 2.5V — the threshold at which the BMS latches into lockout to prevent damage. A standard charger or USB cable will not revive it from this state because the BMS blocks incoming current. Connect the phone to a wall charger and leave it untouched for 15–20 minutes; the charge IC applies a trickle current that slowly raises the cell voltage above the BMS re-enable threshold. Once it crosses approximately 2.7V, the BMS unlocks and normal charging resumes.