HTC EVO 4G LTE Replacement Battery BJ75100 3.8V 2000mAh

HTC EVO 4G LTE / One XC — 3.8V Li-Polymer Replacement Battery (BJ75100)

This is a 3.8V, 2000mAh Li-Polymer cell that fits the HTC EVO 4G LTE, EVO One, One XC, and X720d smartphones. It replaces OEM part numbers BJ75100, 35H00188-00M, 35H00188-00P, 35H00191-00M, BM35100, and 35H00197-04M. The cell measures 60.50 × 54.00 × 4.80 mm and slots directly into the original battery bay.

• EVO 4G LTE and One XC platform fit: These models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers all listed variants because HTC used the same power rail and connector across this hardware generation.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on an EVO 4G LTE. The BMS accepted charge without fault flags, voltage held steady under display and modem load, and the fuel gauge IC began tracking within the first cycle.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge to 100% uninterrupted. This lets the fuel gauge IC map the new cell's discharge curve before taking any high-current charge cycles. Skipping this step causes erratic percentage readings for days.

Sudden shutdown at 20–30% on the EVO 4G LTE after a cell swap

This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. When the new cell hits a voltage point that the old curve mapped to 20–30%, the phone treats it as a safe-shutdown threshold and cuts power. The fix is one full discharge-to-shutdown followed by an uninterrupted charge to 100%. After that cycle, the coulomb counter resets against the actual new cell curve and the early shutdowns stop.

Phone won't power on after the replacement battery sat in storage

Li-Polymer cells self-discharge in storage. If the cell drops below approximately 2.5V, the BMS enters lockout mode and blocks charge current to prevent damage. The phone appears completely dead — no boot, no charge indicator. Connect to a wall adapter rather than a PC port, which supplies stable 5V at higher current. Leave it connected for 15–20 minutes without pressing the power button; the BMS needs sustained voltage to exit lockout before the phone can boot.