Coolpad Y91-921 Replacement Battery CPLD-395 3.8V 2500mAh

Coolpad Y91-921 / Fengshang Pro 2 — 3.8V Li-Polymer Replacement Battery (CPLD-395)

This 3.8V, 2500mAh Li-Polymer cell replaces the original CPLD-395 battery in the Coolpad Y91-921, Fengshang Pro 2, Fengshang Pro 2 Dual SIM, and related Fengshang Pro 2 TD-LTE variants. It fits the same 78.90 × 61.50 × 3.10 mm footprint as the factory cell. Capacity is rated at 9.5Wh — identical to the OEM specification.

• Fengshang Pro 2 platform compatibility: All listed Fengshang Pro 2 variants — standard, Dual SIM, and TD-LTE — share the same battery bay geometry, connector pinout, and BMS handshake protocol. Swapping between these models is not required; the CPLD-395 part number covers the full set.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a Coolpad Y91-921 unit. The BMS accepted the charge handshake on the first connection, current regulation stepped correctly at 80% state of charge, and the protection circuit tripped at the expected undervoltage threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins — skipping this step causes the percentage counter to read incorrectly for the first several cycles.

Sudden shutdown at 20–30% on the Coolpad Y91-921

This is a voltage cliff, not a capacity problem. When the modem transmits at full power or the screen runs at peak brightness, the cell must sustain high current draw. An aged or deeply discharged cell cannot hold its terminal voltage under that load, so the protection circuit cuts output even though the fuel gauge still shows charge remaining. The replacement cell restores the voltage headroom the modem needs. If shutdowns persist after fitting the new cell, charge to 100% and run one full discharge cycle so the coulomb counter resets its endpoint calibration.

Phone not powering on after the battery sat in storage

Li-Polymer cells left uncharged for extended periods can drop below 2.5V per cell, which triggers BMS lockout — the circuit physically disconnects output to prevent damage. The phone shows no response to the power button and no charge indicator on the screen. Connect the phone to a wall adapter, not a PC USB port, and leave it undisturbed for 15–20 minutes before attempting to power on. If the BMS recovers, the charge LED will activate; at that point, allow a full charge to 3.8V before normal use.