Certain vehicle models, particularly PHEVs (Plug-in Hybrid Electric Vehicles), have a default setting that limits the maximum charge for DC fast charging to 80%. This deliberate limitation is designed to enhance the overall lifespan of the battery. It's worth noting that this practice may extend to other EVs as well.
Depending on your specific vehicle model, you may have the option to modify this charging setting. Check your vehicle's manual or consult with the manufacturer to explore customisation options based on your preferences and charging needs.