Asus B11P1406 PadFone X Mini 4.5 Compatible Battery 3.8V 2000mAh

Asus PadFone X Mini 4.5 — 3.8V Li-ion Replacement Battery (B11P1406)

This is a 3.8V 2000mAh Li-ion replacement battery for the Asus PadFone X Mini 4.5 and PadFone X Mini 4.5 4G smartphones, including models PF450CL and T005. It matches OEM part numbers B11P1406 and 0B200-01110000. Dimensions are 85.56 × 41.46 × 4.65mm — swap only if your original cell matches that footprint.

• PadFone X Mini 4.5 and 4G variants: The PF450CL and T005 share an identical battery bay, connector pinout, and BMS handshake requirement. All listed models pull from the same 3.8V rail with the same charge-termination voltage, so one cell covers the full group without any wiring or bracket modification.
• Bench tested on actual hardware: We cycled this cell through charge and load on a PF450CL unit. The BMS accepted the charge handshake on the first connect, voltage held steady at 3.8V nominal, and the protection circuit triggered correctly at both overvoltage and undervoltage thresholds.
• First-cycle fuel gauge reset: After installing this cell, disable fast charging and run one full discharge-to-charge cycle before normal use. The fuel gauge IC on the PadFone X Mini calibrates its coulomb counter against the actual discharge curve — skipping this step leaves the IC mapping a new cell against the old cell's learned data, which causes percentage errors from day one.

Sudden shutdown at 20–30% on the PadFone X Mini after a cell swap

This happens when the fuel gauge IC still holds calibration data from the degraded original cell. The new cell has a steeper voltage drop near the bottom of its discharge curve, so the phone's SoC hits a voltage floor the IC wasn't expecting and forces a hard shutdown before the display percentage reaches zero. It is not a fault with the replacement cell — it is a calibration mismatch. Run two full discharge-charge cycles without fast charging and the IC will relearn the curve. After that, shutdowns should stop above 5%.

PadFone X Mini not powering on after the replacement battery sat in storage

Li-ion cells shipped or stored for extended periods can drop below 2.5V per cell, which triggers a BMS lockout — the protection circuit disconnects the cell to prevent damage and the phone shows no response at all. Plug into a wall charger, not a USB port, and leave it for 20–30 minutes without attempting to power on. Most BMS circuits on this cell will begin a trickle pre-charge at low voltage and release the lockout once the cell reaches approximately 3.0V, at which point the phone will boot normally.