ZTE Z965 Li3930T44P6h816437 Compatible Battery 3.85V 3000mAh

ZTE Z965 / Blade X — 3.85V Li-Polymer Replacement Battery (Li3930T44P6h816437)

This is a 3.85V, 3000mAh (11.55Wh) lithium-polymer cell that fits the ZTE Z965 and ZTE Blade X smartphones. It replaces OEM part number Li3930T44P6h816437 and matches the original connector, dimensions, and BMS handshake. The cell measures 79.30 × 63.18 × 3.45mm — check clearance before installing if your unit has third-party adhesive residue from a previous swap.

• Z965 and Blade X shared platform: Both devices run on the same voltage rail and use the same connector pinout, so they share this cell. The BMS on each model negotiates charge termination the same way — no firmware conflict between variants.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Z965 platform. The BMS accepted the full 3000mAh rated capacity, held charge termination correctly at 4.35V, and did not trip low-voltage cutoff during a simulated modem and display load.
• Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC one full reference cycle against the new cell's discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the Z965 after a cell swap

The Z965's fuel gauge IC stores a discharge curve from the original cell. A new cell has a different internal resistance profile, so the IC miscalculates remaining capacity. Under modem load — during a call or LTE data burst — the cell voltage sags below the shutdown threshold before the percentage reaches zero. The phone cuts out even though the display showed charge remaining. One full discharge-charge cycle without fast charging resets the coulomb counter and maps the new cell's actual voltage cliff, usually sitting around 3.4–3.5V under load.

USB fast charge not activating on the first cycle after replacement

On the first charge after installation, the charge IC on the Z965 may default to standard 5V/1A input and not negotiate the higher voltage profile. This happens because the BMS on a new cell starts with conservative thresholds until it confirms cell temperature and impedance are within range. Plug the phone in for a full uninterrupted charge at standard rate — do not disconnect mid-cycle. On the second charge, the IC typically resumes fast charge negotiation once the BMS has cleared its first-cycle validation check at 4.35V termination.