Here’s an example of voltage-based gauging. As seen before, there is a finite/nonzero offset between the OCV discharge curve of a cell versus the actual curve when a load is applied. This offset is variable depending on the load current and the internal resistance of the battery. As seen here, a voltage just under 3.9V might be nearly full if load current is being drawn, but possibly around 60% full at zero or light load current levels. If the load current pulses on and off, the display of the battery capacity is likely to flicker between two and three bars.