About this replacement
ZTE Axon M Series — 3.85V Li-Polymer Replacement Battery (Li3931T44P8h686049)
This 3.85V, 3000mAh (11.55Wh) Li-Polymer cell replaces the original battery in the ZTE Axon M, Axon M LTE-A, Z-01K, and Multy. The Axon M is a dual-screen foldable smartphone, and this cell slots into the main battery bay. OEM part number Li3931T44P8h686049 confirms fitment across the listed variants.
- Dual-screen power draw: The Axon M runs two independent display panels off a single cell. Both panels share the same voltage rail, so the BMS must handle current spikes when both screens are active simultaneously. This cell matches the 3.85V nominal and the connector pinout the BMS handshake expects.
- Bench tested on actual hardware: We cycled the cell through full charge and discharge on the Axon M platform. The BMS accepted the new cell without flags, the fuel gauge IC initialised, and charge termination triggered correctly at top-of-charge voltage.
- First-cycle fast charge behaviour: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC recalibrate its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.
Why the Axon M reports wrong battery percentage after a cell swap
The fuel gauge IC builds its capacity model from the previous cell's charge history. After a swap, that stored curve no longer matches the new cell's actual discharge profile. Until the IC runs one complete discharge-charge cycle, the percentage reading can be off by 10–20%. One full cycle from 100% down to auto-shutdown and back to 100% resets the coulomb counter to the new cell's real capacity.
Sudden shutdown at 20–30% on the replacement cell
This happens when the cell voltage drops below the modem or dual-display load threshold before the fuel gauge reports 0%. Under peak load — both screens active, LTE active — a cell with any internal resistance will sag in voltage faster than the percentage indicator tracks. The BMS cuts power to protect the cell the moment rail voltage crosses the low-voltage cutoff, typically around 3.4V under load. Run the recalibration cycle described above; if shutdowns persist after two full cycles, check that the connector is fully seated and the cell is not swollen.