HTC One X9 B2PS5100 Replacement Battery 3.85V 3000mAh

HTC One X9 Series — 3.85V Li-Polymer Replacement Battery (B2PS5100)

This is a 3.85V, 3000mAh (11.55Wh) Li-Polymer cell replacing the original B2PS5100 in the HTC One X9, One X9E, One X9u, and One X9 Dual SIM. It fits the same footprint as the OEM cell at 76.50 × 67.90 × 3.40mm. When the original cell degrades and can no longer hold voltage under load, this cell restores full function.

• One X9 variant compatibility: The X9, X9E, X9u, and Dual SIM variants all share the same battery bay dimensions, connector pinout, and 3.85V nominal rail — the BMS handshake is identical across these builds, so one cell covers the full range.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an HTC One X9 unit. The BMS accepted the cell cleanly, protection circuits triggered correctly at low-voltage cutoff, and the charge IC stepped through CC/CV phases without fault.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This allows the fuel gauge IC to recalibrate against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the One X9 after a cell swap

The One X9's fuel gauge IC builds its percentage model from the old cell's discharge curve. A new cell has a different internal resistance profile, so the IC misjudges how much voltage remains under modem and display load. The phone hits a hard voltage floor — around 3.4V under peak draw — before the percentage reaches zero. One full discharge-charge cycle without fast charging gives the coulomb counter enough data to replot the curve against the new cell.

Device not powering on after sitting in storage with a flat battery

Li-Polymer cells that drop below approximately 2.5V per cell trigger a BMS lockout to prevent damage during recharge. The One X9 will show no response — no boot logo, no charge indicator — until the BMS is brought out of lockout. Connect to a wall charger, not a PC USB port, and leave it for 20–30 minutes without pressing the power button. Once the BMS detects safe voltage recovery, the charge indicator will appear and normal charging resumes.