ZTE F252 Li-ion Replacement Battery 3.7V 700mAh

ZTE F252 / F850 Series — 3.7V Li-ion Replacement Battery (Li3707T42P3h513651)

This is a 3.7V, 700mAh Li-ion cell built to replace the original battery in ZTE F252, F256, F850, and F851 handsets. All four models share the same battery footprint and connector, so one cell covers the full group. Capacity matches the OEM spec at 700mAh (2.59Wh).

• F252 / F256 / F850 / F851 platform fit: These four ZTE models run the same 3.7V power rail and use an identical connector pinout and BMS handshake, which is why a single replacement cell works across the whole group.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the F850 platform. The BMS accepted the cell without fault codes, charge termination triggered correctly at full voltage, and low-voltage cutoff engaged cleanly at the expected floor.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one full discharge down to auto-shutoff, then charge uninterrupted to 100%. This gives the fuel gauge IC a complete reference curve against the new cell before normal use resumes.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC still holds the discharge curve from the old, degraded cell. When the new cell hits a steeper voltage drop under screen or modem load, the IC has no matching reference point and the phone shuts down before the display reaches 0%. The fix is one full reference cycle — discharge to auto-shutoff, then charge to 100% without interruption. After that cycle the coulomb counter recalibrates and reported percentage tracks actual cell voltage correctly.

Phone won't power on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the cell dropped below roughly 2.5V per cell, the BMS enters lockout mode to prevent damage and the phone shows nothing when you press the power button. Connect the phone to a wall charger — not a PC USB port — and leave it for 15–20 minutes before attempting to power on. The charge IC needs enough current to push the cell voltage back above the BMS re-enable threshold, typically around 2.9V, before the handset will boot.