About this replacement
ZTE Axon Max C2016 Series — 3.85V Li-Polymer Replacement Battery (Li3940T44P8h907043)
This 3.85V 4000mAh Li-Polymer battery replaces part number Li3940T44P8h907043 in the ZTE Axon Max C2016, Axon Max C2016 Dual SIM, Axon 7 Max, and Axon 7 Max C2017. It fits the original battery bay without modification. Capacity is 15.4Wh, matching the factory specification.
- Axon Max and Axon 7 Max compatibility: These models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The 88.80 × 69.50 × 4.50mm cell fits all listed variants without adapter or rewiring.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the Axon Max platform. The BMS accepted the cell without fault flags, and the charge IC stepped through trickle, CC, and CV phases correctly at each stage.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes into an uncalibrated state.
Sudden shutdown at 20–30% on the Axon Max after a cell swap
The Axon Max fuel gauge IC stores a discharge model calibrated to the original cell. A new cell with a different internal resistance profile hits a voltage cliff at a different state of charge than the IC expects. When the modem, screen, or GPS pulls a high current spike, the cell voltage drops below the BMS cutoff threshold even though the reported percentage reads 20–30%. One full slow discharge-charge cycle rewrites the coulomb counter baseline and pushes the shutdown point back to the correct level.
USB fast charge not activating on the first cycle after replacement
ZTE's charge controller runs a handshake check before enabling fast charge. On the first cycle with a new cell, the BMS reports an uncalibrated state and the controller defaults to standard 5V charging as a precaution. This is not a fault — it clears after the first complete charge cycle. Confirm fast charge is active by checking the charging indicator in Settings → Battery after the second full charge.