SoftBank V402SH Replacement Battery SHBV01 3.7V 700mAh

SoftBank V402SH — 3.7V Li-ion Replacement Battery (SHBV01)

This is a 3.7V, 700mAh Li-ion replacement battery for the SoftBank V402SH mobile handset. It carries OEM part number SHBV01 and fits the V402SH directly. Capacity figures come from the product data: 700mAh / 2.59Wh.

• V402SH platform fit: The V402SH uses a compact 3.7V single-cell Li-ion pack with a low-profile connector. This replacement matches the original voltage rail and physical footprint — 41.79 × 35.54 × 5.44mm — so the BMS handshake between the pack and the handset's charge IC stays intact.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench and confirmed the BMS responds correctly to the V402SH charge IC. Charge termination triggers at the correct cutoff voltage and the protection circuit trips cleanly on overcurrent without latching the pack into lockout.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one full discharge-to-charge cycle before resuming normal use. The V402SH fuel gauge IC calibrates its coulomb counter against the cell's discharge curve — skipping this step leaves the gauge tracking the old cell's curve, which causes erratic percentage readings from day one.

Sudden shutdown at 20–30% on the V402SH after a cell swap

The V402SH's fuel gauge IC was calibrated to the original cell's internal resistance profile. A new cell has lower impedance, so the voltage curve under modem and screen load looks different to the gauge. When the handset draws a burst of current — during a call, a screen wake, or a data sync — cell voltage can sag below the shutdown threshold even though the gauge still reads 20–30%. The phone interprets this as a protection event and cuts power. One full discharge cycle, draining to auto-shutdown then charging uninterrupted to 100%, resets the gauge's reference points against the new cell curve.

Device not powering on after the replacement cell sat in storage

Li-ion cells self-discharge in storage, and if a pack drops below approximately 2.5V per cell, the BMS enters a low-voltage lockout state to prevent damage. The V402SH will show no response — no boot screen, no charging indicator — when connected to a charger in this state. Connect the phone to a wall adapter (not a USB port on a PC) and leave it undisturbed for 15–20 minutes. The charge IC trickle-charges the cell at a reduced current to bring it above the BMS re-enable threshold, after which normal charging resumes and the phone powers on.