ZTE Nubia N2 Li3950T44P6h Compatible Battery 3.85V 4900mAh

ZTE Nubia N2 / NX575J — 3.85V Li-Polymer Replacement Battery (Li3950T44P6h856751)

This is a 3.85V, 4900mAh lithium-polymer replacement battery for the ZTE Nubia N2, Nubia N2 Dual SIM, Nubia N2 Dual SIM TD-LTE, and NX575J. It matches the OEM part number Li3950T44P6h856751 and slots into the same battery bay as the original cell. Dimensions are 83.56 × 67.30 × 4.74mm — measure your bay before ordering if you are unsure.

• Nubia N2 and NX575J platform fit: The N2 and NX575J share the same battery bay geometry, connector pinout, and BMS handshake protocol. One cell covers all four listed variants because the fuel gauge IC communicates over the same data line across the TD-LTE and Dual SIM builds.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on an NX575J unit. The BMS accepted charge, the fuel gauge IC registered state-of-charge correctly after one full cycle, and the protection circuit tripped at the expected low-voltage cutoff threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. 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 cell.

Sudden shutdown at 20–30% on the Nubia N2 after a cell swap

This happens because the fuel gauge IC still holds the discharge curve from the old, degraded cell. When the new cell hits a voltage point the IC associates with 20–30% remaining on the old curve, it triggers a shutdown before the actual charge is depleted. The modem and display draw spikes during calls or screen-on events accelerate the voltage cliff effect. Run one full discharge to below 5% and a full charge to 100% without interruption — the IC relearns the curve and the premature shutdowns stop.

USB fast charge not activating on the first cycle after replacement

The Nubia N2 charge IC checks BMS state before negotiating the fast-charge protocol. On a freshly installed cell, the BMS may not pass the handshake criteria on the first cycle because its internal registers are not yet populated with cycle history. The phone defaults to standard 5V charging as a precaution. Charge fully at standard rate first, let the phone boot and idle for a few minutes, then reconnect — fast charge typically activates from the second cycle onward once the BMS registers a valid first cycle.