About this replacement
ZTE Blade V7 Max — 3.85V Li-Polymer Replacement Battery (Li3930T44P8h866534)
This 3.85V, 3000mAh lithium-polymer cell replaces the original battery in the ZTE Blade V7 Max and Blade V7 Max Dual SIM. It matches the OEM part number Li3930T44P8h866534 and fits the 85.00 × 64.72 × 3.26mm battery bay. Capacity is rated at 11.55Wh, in line with the factory specification.
- Blade V7 Max and Dual SIM compatibility: Both variants share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers both configurations — no adapter or modification needed.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the Blade V7 Max platform. The BMS accepted the cell without fault flags, the fuel gauge IC tracked state-of-charge across the full curve, and charge termination triggered correctly at 4.35V.
- First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. This allows the fuel gauge IC to recalibrate its coulomb counter against the new cell's actual discharge curve before high-current charging is introduced into an uncalibrated cell.
Why the Blade V7 Max shuts down suddenly at 20–30% after a cell swap
The Blade V7 Max uses a coulomb-counter fuel gauge IC that was calibrated to the original cell's internal resistance profile. A new cell has a different impedance curve, so the reported percentage diverges from true state-of-charge. When the modem fires a high-current burst or the display ramps brightness, voltage drops sharply below the BMS cutoff threshold — even though the gauge still reads 20–30%. One full discharge-charge cycle without fast charging corrects this by resetting the counter against the new cell's actual characteristics.
Phone won't power on after the replacement cell sat in storage
Li-polymer cells self-discharge during storage, and if the voltage drops below approximately 2.5V per cell the BMS enters a lockout state to prevent damage. The phone will show no response when the power button is pressed. Connect the device to a wall charger — not a PC USB port — and leave it for 15–20 minutes before attempting to power on. Most BMS circuits re-initialise once the cell climbs back above 3.0V and the charger IC is delivering stable current.