VIBO A688 Replacement Battery 3.7V 1100mAh Li-ion

VIBO A688 — 3.7V Li-ion Replacement Battery

This is a 3.7V 1100mAh Li-ion cell built to replace the original battery in the VIBO A688 smartphone. It fits the A688 directly, restoring power to a phone that no longer holds a charge or fails to power on. Capacity is 1100mAh (4.07Wh), matching the original cell specification.

• A688 fit notes: The A688 uses a compact 46.00 x 40.10 x 6.30mm cell with a direct connector tab. This replacement matches those dimensions exactly, so the battery seats flush without pressure on the rear housing.
• Bench tested on actual hardware: We cycled this cell through a full discharge and charge sequence on the bench. The BMS accepted charge input without tripping, and the protection circuit responded correctly to over-discharge cutoff near 2.5V.
• Fuel gauge recalibration on first install: After fitting this cell, disable fast charging for the first complete discharge-charge cycle. The fuel gauge IC in the A688 was calibrated to the old cell's discharge curve — running one slow cycle lets it map the new curve before high-current charging begins.

Why the A688 reports wrong battery percentage after a cell swap

The A688 uses a fuel gauge IC that tracks charge state by measuring voltage and current over time against a stored discharge curve. When you install a new cell, that stored curve no longer matches the physical cell in the device. The gauge reads voltage accurately but maps it to the wrong state-of-charge percentage. One full slow discharge to 3.2V followed by a complete charge cycle forces the IC to re-anchor its calibration to the new cell.

Sudden shutdown at 20–30% remaining on the replacement cell

This happens when the cell voltage drops sharply under load — typically during a call, screen-on burst, or GPS fix — faster than the fuel gauge predicts. The phone's low-voltage protection cuts power before the displayed percentage reaches zero. It is not a faulty battery; it is the gauge reading a voltage cliff it has not yet learned. Run two full discharge-charge cycles without fast charging, then check whether the shutdowns persist. If the phone still cuts out, charge to 100% and verify the resting cell voltage sits above 4.1V before discharge begins.