HB5N1 Huawei Ascend Replacement Battery 3.7V 1800mAh Li-ion

Huawei Ascend Series — 3.7V Li-ion Replacement Battery (HB5N1)

This is a 3.7V, 1800mAh Li-ion cell built to replace the OEM HB5N1 and HB5N1H batteries. It fits the Huawei Ascend, Ascend C8812, Ascend G300, Ascend G302D, and over 39 additional Ascend variants. When the original cell degrades and can no longer hold a stable charge, this unit restores full function to the handset.

• Ascend platform compatibility: The Ascend G300, G302D, and C8812 share the same 3.7V single-cell architecture, HB5N1 connector pinout, and BMS handshake protocol — which is why one cell covers the full range. The battery management IC communicates charge state identically across each model in this lineup.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on Ascend hardware. The BMS engaged thermal and overcurrent cutoffs correctly at expected thresholds, and charge acceptance was clean from the first cycle.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-to-charge cycle before normal use. This gives the fuel gauge IC time to map the new cell's discharge curve — without it, the coulomb counter reads against the old cell's profile and percentage reporting drifts.

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

This happens because the fuel gauge IC was calibrated to the worn original cell, which had a flattened discharge curve near end-of-life. The new cell has a steeper voltage cliff at low charge states. When the modem transmits or the screen brightens, load current spikes and the cell voltage drops sharply — the BMS trips the output before the OS has time to shut down gracefully. One full discharge cycle from 100% to automatic power-off, followed by an uninterrupted charge to 100%, resets the coulomb counter to the new cell's actual curve. After that cycle, shutdowns at 20–30% stop.

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

Li-ion cells shipped or stored in a low-charge state can drop below 2.5V per cell during extended storage. At that voltage, the BMS locks the output rail to prevent damage and the phone shows nothing when the power button is pressed. Plug into a wall charger — not a PC USB port — and leave it for 15–20 minutes without pressing any buttons. Most Ascend charger ICs trickle current into a locked-out cell at around 100mA until the voltage recovers above 3.0V, at which point the BMS unlocks and the charging indicator appears. If the screen stays blank past 30 minutes on a wall charger, check the charge port for debris before replacing the cell.