ZTE Blade V60 Vita Replacement Battery BL-49S 3.85V 4900mAh

ZTE Blade V60 Vita / Nubia V60 Series — 3.85V Li-Polymer Replacement Battery (BL-49S-976546)

This is a 3.85V, 4900mAh (18.87Wh) lithium-polymer cell built to replace the original BL-49S-976546 in the ZTE Blade V60 Vita, Nubia V60, and Nubia V60 Design. The original cell degrades after repeated charge cycles, causing capacity loss, unexpected shutdowns, or complete failure to hold charge. Swapping this cell restores the phone to full operating capacity.

• Blade V60 Vita, Nubia V60, and Nubia V60 Design compatibility: All three models share the same battery bay dimensions, connector pinout, and BMS handshake protocol tied to the BL-49S-976546 part number — one cell fits all three without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the Blade V60 Vita. The BMS accepted the cell without triggering protection cutoff, and the fuel gauge IC registered capacity correctly after one full calibration cycle.
• 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 the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell — prevents erratic percentage readings from the start.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still calibrated to the old cell's discharge curve. The new cell hits a voltage cliff — the point where cell voltage drops sharply under modem or screen load — at a different state of charge than the old cell did. The phone reads 25% but the actual cell voltage has already fallen below the shutdown threshold. One full discharge cycle from 100% to automatic shutdown, followed by a full charge, lets the coulomb counter recalibrate against the new cell. After that cycle, the percentage reading tracks accurately.

USB-PD fast charge not working on the first cycle after replacement

A new high-impedance cell can cause the charge IC to fall back to standard 5V charging on the first cycle. The BMS on a fresh cell has not yet completed its internal resistance characterisation, so the fast-charge handshake stalls as a protective measure. Run one standard charge to completion without fast charging enabled. On the second and subsequent cycles, the charge IC re-negotiates the fast-charge protocol correctly and full charging speed resumes.