ZTE Blade Q Maxi Li3720T43P4h825839 Compatible Battery 3.8V 2000mAh

ZTE Blade Q Maxi — 3.8V Li-ion Replacement Battery (Li3720T43P4h825839)

This is a 3.8V, 2000mAh Li-ion replacement battery for the ZTE Blade Q Maxi smartphone. It matches the OEM part number Li3720T43P4h825839 and fits directly into the original battery compartment. Swap this in when the original cell no longer holds a usable charge or causes unexpected shutdowns.

• Blade Q Maxi cell compatibility: The Blade Q Maxi uses a single-cell 3.8V Li-ion configuration with a fixed connector pinout. This replacement matches that pinout and the BMS communication protocol the phone's charge IC expects — no adapter or wiring modification needed.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Blade Q Maxi platform. The BMS accepted the cell on the first connection, charge termination triggered correctly at 4.35V, and the protection circuit tripped cleanly at the low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's discharge curve before any high-current session pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the Blade Q Maxi after a cell swap

This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. The new cell has a steeper voltage drop under modem and display load, and the phone's reported percentage doesn't reflect that accurately yet. When voltage sags below the hardware cutoff threshold — typically around 3.4V under load — the phone shuts off even though the reported percentage looks safe. One full discharge-charge cycle at standard current resets the coulomb counter and eliminates this behaviour.

Phone not powering on after the replacement battery sat in storage

Li-ion cells self-discharge in storage. If this battery shipped or was stored for an extended period, the cell voltage may have dropped below 3.0V — at that point the BMS engages a lockout to prevent charging a critically low cell. Plug the phone into a wall charger, not a PC USB port, and leave it for 20–30 minutes without attempting to power it on. The charge IC needs to trickle current into the cell until it clears the 3.0V recovery threshold before normal charging and boot can begin.