ZTE U880 Li-ion Replacement Battery 3.8V 1950mAh

ZTE U880 / N880s Series — 3.8V Li-ion Replacement Battery (Li3717T43P3H565751)

This is a 3.8V, 1950mAh Li-ion cell built to fit the ZTE U880 and its close relatives — the N880s, N855D, U880E, and six additional variants sharing the same battery bay. It replaces OEM part numbers Li3717T43P3H565751 and Li3717T43P3H565751-H. If your original cell is bulging, no longer holding a charge, or draining faster than it used to, this is a direct swap.

• U880 / N880s family compatibility: These models share the same 3.8V voltage rail, connector pinout, and BMS handshake protocol across the series. The cell dimensions — 56.00 × 55.50 × 5.00mm — match the battery bay on all listed variants, so no modification is needed at the connector or housing level.
• Bench tested on actual hardware: We cycled this cell on U880-series hardware and confirmed the BMS accepted the charge profile without triggering an overcurrent fault. The protection circuit tripped correctly at low-voltage threshold, and the charge IC resumed normally after recovery.
• Fuel gauge recalibration on first use: On first installation, disable fast charging and run one full discharge-to-charge cycle at standard rate. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC starts pushing higher current into an uncalibrated cell — otherwise the percentage readout drifts from the first charge onward.

Sudden shutdown at 20–30% on the ZTE U880 after a cell swap

This is a voltage-cliff failure, not a capacity problem. When the modem radio or display fires a high-draw burst, the new cell's voltage drops sharply under load — faster than the fuel gauge IC expects based on the old cell's discharge curve it still has stored. The phone's under-voltage protection reads that sag as a dead cell and cuts power immediately, even though the reported percentage looks fine. One complete discharge-charge cycle at standard rate resets the coulomb counter and teaches the IC where the real cutoff sits on the new cell.

ZTE U880 reporting erratic or incorrect battery percentage after replacement

The fuel gauge IC on the U880 tracks charge state using a coulomb counter that was calibrated against the original cell's internal resistance and discharge curve. Drop in a new cell and those stored values no longer match the physical reality of what's in the phone. The result is percentage readings that jump, stall, or show full charge well before the cell is actually full. Drain the phone fully until it shuts off from low battery, then charge it uninterrupted to 100% — this forces the IC to reset its reference points against the new cell. After one clean cycle, percentage tracking stabilises.