ZTE E700 F860 F868 F866 Replacement Battery Li3712T42P3h633959 3.7V 1200mAh

ZTE E700 / F860 / F868 / F866 — 3.7V Li-ion Replacement Battery (Li3712T42P3h633959)

This 3.7V Li-ion cell delivers 1200mAh (4.44Wh) and fits the ZTE E700, F860, F868, F866, and I909 smartphones. It replaces the OEM cell under part number Li3712T42P3h633959. Use it when the original battery no longer holds a usable charge across a full day.

• E700, F860, F868, F866, and I909 compatibility: These models share the same 3.7V battery bay, connector pinout, and BMS handshake protocol, which is why a single cell covers all five. The Li3712T42P3h633959 part number maps directly to this shared platform spec.
• Bench tested on actual hardware: We ran the cell through charge and discharge cycles on compatible hardware. The BMS accepted full charge without triggering protection cutoff, and the fuel gauge IC responded correctly to the cell's discharge curve without erratic readings.
• First-cycle fuel gauge calibration: 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 — preventing early percentage drift.

Why the ZTE F860 reports wrong battery percentage after a cell swap

The fuel gauge IC on these ZTE models stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches actual cell voltage behaviour. The gauge reads against the old profile, so the percentage displayed can be 10–20% off until the IC relearns. One full uninterrupted discharge down to automatic shutdown, followed by a full charge to 4.2V, resets the calibration data and brings percentage readings back into line.

Sudden shutdown at 20–30% on a freshly installed cell

This happens when the modem or display draws a high-current burst and the cell voltage drops sharply below the BMS cutoff threshold — even though the gauge still shows charge remaining. It is a voltage cliff issue, not a capacity fault. A fresh Li-ion cell at room temperature is more susceptible to this until internal resistance stabilises after a few cycles. If the shutdowns persist past three full cycles, check that the battery contacts are clean and making solid connection — oxidised contacts add resistance and deepen the voltage sag under load.