Huawei M750 Replacement Battery HB5A2H 3.7V 1100mAh

Huawei M750 / U7519 Series — 3.7V Li-ion Replacement Battery (HB5A2H)

This is a 3.7V, 1100mAh Li-ion replacement battery for the Huawei M750, U7519, M228, C8000, and related models. It uses OEM part number HB5A2H (also cross-referenced as BTR7519). Physical dimensions are 54.05 × 34.10 × 5.40mm — measure your existing cell before ordering if you are unsure which variant you have.

• M750 / U7519 platform fit: These models share the same 3.7V single-cell architecture, physical footprint, and connector orientation. The BMS handshake on each device expects the same charge termination voltage, so one cell revision covers the full compatibility list without modification.
• Bench tested on actual hardware: We cycled this cell through charge and load on the M750 platform. The BMS accepted the cell on first insertion, charge termination triggered correctly at 4.2V, and protection cutoff activated as expected under a simulated low-voltage discharge.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. The fuel gauge IC in these devices calibrates against the cell's discharge curve — skipping this step causes the percentage counter to drift against the new cell's actual capacity.

Sudden shutdown at 20–30% on the M750 after a cell swap

This is a voltage cliff failure, not a capacity problem. The fuel gauge IC still holds the discharge curve from the old, degraded cell and predicts remaining charge incorrectly. When the modem fires a high-current burst — during a call or data sync — the new cell's actual voltage drops below the shutdown threshold before the percentage counter reaches zero. One full discharge cycle from 100% to automatic power-off, followed by a full charge, gives the coulomb counter enough data to rebuild an accurate curve against the replacement cell.

Device not powering on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell voltage has dropped below approximately 2.5V, the BMS enters lockout mode and will not pass current to the device — the phone shows no sign of life even on charge. Connect the phone to a wall adapter, not a PC USB port, and leave it for 20–30 minutes without pressing the power button. The charge IC needs sustained input voltage to trickle the cell above the BMS re-enable threshold of around 2.9V before normal charging resumes.