Haier H-U55T Replacement Battery 3.7V 750mAh

Haier H-U55T / HE-D330 Series — 3.7V Li-ion Replacement Battery

This 3.7V 750mAh Li-ion cell replaces the original battery in the Haier H-U55T, H15132, HE-D330, HE-M002, and three additional models in this series. Physical dimensions are 53.00 × 33.90 × 5.70mm — measure your existing cell before ordering if your exact variant is not listed. Capacity matches the stock specification at 2.78Wh.

• Multi-model fit across the H-U55T lineup: These handsets share the same battery footprint, voltage rail, and connector pinout. The BMS handshake protocol is identical across the series, so one cell covers all listed variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a compatible unit. The BMS accepted the cell without error flags, charge termination triggered correctly at full voltage, and the protection circuit responded to a simulated over-discharge condition as expected.
• Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. The fuel gauge IC is calibrated to the old cell's discharge curve — running one full cycle at standard current lets it map the new cell before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the H-U55T after a cell swap

This happens because the fuel gauge IC is still reading the discharge curve of the old, degraded cell. The new cell has a steeper voltage drop near the bottom of its curve than the worn cell did, so the phone's modem or display draws enough current to pull the voltage below the BMS cutoff threshold before the percentage counter reaches zero. The phone shuts off because actual cell voltage has collapsed, not because charge is genuinely exhausted. Run one full discharge to automatic shutdown, then charge uninterrupted to 100% — after that single cycle the coulomb counter resets to the new cell's curve and low-percentage shutdowns stop.

Phone won't power on after sitting in storage for several months

Li-ion cells self-discharge during storage. If the cell drops below approximately 2.5V, the BMS enters lockout mode and blocks current flow to protect against unsafe charging of a deeply discharged cell. Plugging in the charger may show no response at all — no charging indicator, no boot. Connect the phone to a wall charger (not a PC USB port) and leave it for 15–20 minutes without pressing the power button; most charge ICs in this class run a trickle pre-charge sequence that brings the cell back above the BMS re-enable threshold of around 2.9V before normal charging resumes.