Alcatel One Touch S680 Replacement Battery 3.7V 900mAh

Alcatel One Touch S680 / OT-S680 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 900mAh Li-ion cell for the Alcatel One Touch S680 and OT-S680 candybar-style handsets. It replaces the original battery when capacity has degraded or the cell no longer holds a charge. Physical dimensions are 46.20 × 34.14 × 5.68mm — verify against your existing cell before fitting.

• One Touch S680 and OT-S680 fit: Both model designations refer to the same handset variant. The S680 uses a fixed connector pinout and housing slot — this cell matches both the contact layout and the compartment depth without modification.
• Bench tested on actual hardware: We cycled this cell through charge and full discharge on S680-class hardware. The protection circuit tripped correctly at low-voltage cutoff, and charge acceptance was consistent from the first cycle through subsequent runs.
• Fuel gauge recalibration on first install: After fitting this cell, run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. The S680's fuel gauge IC was calibrated to the original cell's discharge curve — one full cycle resets that reference so percentage readings track accurately from the start.

Why the S680 reports wrong battery percentage after a cell swap

The S680 uses a fuel gauge IC that tracks charge state against a stored discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual cell chemistry and impedance. The IC keeps reporting against the old reference, so the percentage shown on screen drifts — often reading full well before the cell is actually full, or dropping suddenly near the end. One complete discharge-to-shutdown followed by a full uninterrupted charge resets the coulomb counter and aligns the gauge to the new cell.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff, not a faulty cell. Under screen-on or active load, the cell voltage sags below the protection circuit's cutoff threshold before the reported percentage reaches zero. It happens most often in the first few cycles when the cell hasn't fully formed. Run two or three full discharge-charge cycles — the voltage sag under load reduces as the cell conditions, and the shutdowns should stop. If the problem persists past three cycles, check that the battery contacts on the handset are clean and making firm contact, since high contact resistance amplifies voltage sag at the same load.