ZTE Blade Z Max Li3940T44P8h937238 Replacement Battery 3.85V 4050mAh

ZTE Blade Z Max / Z982 — 3.85V Li-Polymer Replacement Battery (Li3940T44P8h937238)

This is a 3.85V, 4050mAh lithium-polymer replacement battery for the ZTE Blade Z Max (Z982) smartphone. It matches the OEM part number Li3940T44P8h937238 and fits the original battery compartment at 92.30 × 71.56 × 3.45mm. Swap it in when the original cell no longer holds enough charge for daily use.

• Blade Z Max / Z982 compatibility: Both model names refer to the same hardware platform. They share the same battery connector, voltage rail, and BMS handshake, so one cell covers both designations without modification.
• Bench tested on actual hardware: We cycled this cell on a Z982 unit and confirmed the BMS accepted the new cell, reported state-of-charge correctly after one full cycle, and held voltage above 3.6V under combined screen and LTE modem load.
• First-cycle fuel gauge recalibration: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before high-current charging is applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the Z982 after a cell swap

The Z982's fuel gauge IC stores a learned discharge curve from the original cell. A new cell with a different internal resistance profile can hit a voltage cliff — where cell voltage drops below the BMS cutoff threshold — while the OS still reads 20–30% remaining. The phone shuts off not because the new cell is faulty, but because the gauge IC hasn't recalibrated yet. One full discharge from 100% to automatic power-off, followed by a full charge, resets the coulomb counter to match the new cell's actual curve.

USB fast charge not activating after replacement

On the first charge cycle after a cell swap, the Z982's charge IC may default to slow 5V/1A charging instead of engaging the faster protocol. This happens because the charge IC runs a brief negotiation handshake on first contact with a new BMS, and some chargers time out before that handshake completes. Use the original ZTE wall adapter — not a third-party USB-PD charger — for the first full charge. Fast charging typically activates normally from the second cycle onward once the BMS has completed its initialisation sequence.