About this replacement
Huawei Ascend G7 / Maimang — 3.8V Li-Polymer Replacement Battery (HB3748B8EBC)
This is a 3.8V, 3000mAh (11.4Wh) lithium-polymer cell built to fit the Huawei C199, C199-CL00, Maimang, and Ascend G7 family. It uses OEM part number HB3748B8EBC and slots into the same battery bay as the original cell. If the original cell is swelling, losing charge overnight, or triggering sudden shutdowns, this is the direct swap.
- Ascend G7 and Maimang series compatibility: These models share the same battery bay geometry, connector pinout, and BMS handshake protocol — all pulling from the same 3.8V nominal rail. The HB3748B8EBC part number spans the full C199 lineup including regional variants like the C199-CL00.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Ascend G7 platform. The BMS accepted the new cell without fault flags, and the charge IC negotiated correctly at both 5V standard and the device's adaptive charging profile.
- First-cycle recalibration after installation: On first use, disable fast charging and run one complete discharge-to-charge cycle. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging pushes amps into an uncalibrated coulomb counter — preventing early percentage-reading errors.
Why the Ascend G7 reports wrong battery percentage after a cell swap
The Ascend G7 uses a coulomb-counting fuel gauge IC that builds its percentage model from the original cell's charge and discharge history. When you install a new cell, that learned curve no longer matches the physical reality of the fresh cell. The gauge will report stale data — sometimes jumping 10–15% in either direction — until it relearns the curve. One full discharge from 100% down to automatic shutdown, followed by a full charge to 100%, resets the counter. After that single cycle, percentage readings stabilise.
Sudden shutdown at 20–30% remaining on the replacement cell
This happens when the modem or display pulls a current spike the cell cannot sustain at that state of charge — the cell voltage drops below the BMS cutoff threshold even though the gauge still reads 20–30%. It is a fuel gauge calibration issue, not a defective cell. The BMS cuts power to protect the cell from going below 3.0V under load. Run one full discharge-charge cycle without fast charging to let the fuel gauge IC relearn the true low-voltage cliff on this cell. After calibration, the shutdown threshold will align with the actual remaining capacity.