ZTE U880S2 Li3712T42P3h484952 Replacement Battery 3.7V 1200mAh

ZTE U880S2 / V880S2 — 3.7V Li-ion Replacement Battery (Li3712T42P3h484952)

This is a 3.7V, 1200mAh Li-ion cell built to fit the ZTE U880S2 and V880S2 smartphones. It replaces the original Li3712T42P3h484952 cell when the existing battery no longer holds charge or swells. Dimensions are 47.85 × 48.86 × 5.15mm — measure your original before ordering if unsure.

• U880S2 and V880S2 compatibility: Both model variants share the same battery bay dimensions, connector pinout, and BMS communication protocol — one cell fits both without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the U880S2 platform. The BMS accepted the cell without fault flags, and the charge IC cycled correctly from cutoff to full termination voltage.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging and run one complete discharge down to automatic shutdown, then charge fully without interruption. This gives the phone's fuel gauge IC a clean reference cycle against the new cell's actual discharge curve before high-current charging begins.

Sudden shutdown at 20–30% on the U880S2 after a cell swap

The U880S2 uses a coulomb-counter fuel gauge that was calibrated to the old cell's internal resistance profile. When a new cell is fitted, the gauge doesn't yet know where the new cell's voltage cliff sits — the point where voltage collapses rapidly under modem or display load. The phone sees the voltage drop faster than expected and triggers an emergency shutdown, even though the reported percentage still shows charge remaining. One full discharge-charge cycle corrects the reference table. After that cycle, reported percentage and actual remaining capacity align correctly.

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

Li-ion cells self-discharge during storage. If this cell dropped below roughly 2.5V before installation, the BMS may have entered a lockout state to prevent damage to the over-discharged cell. Plugging into a charger may show no response at all — no charging LED, no boot. Connect the phone to a wall adapter rated at 5V and leave it for 20–30 minutes without attempting to power on. The charge IC will trickle current into the cell until voltage recovers above the BMS re-enable threshold, after which normal charging and boot behaviour resumes.