Futurology

The 97 per cent limit was chosen for a specific reason. During a demonstration, BYD chairman Wang Chuanfu explained that ending the charging process at 97 per cent is a deliberate energy-saving measure. The remaining three per cent is reserved for regenerative braking, which helps reduce the vehicle’s overall energy consumption.

There are some good reasons for designing the system that way, but its irksome that its framed as an energy saving measure. The energy required to accelerate a vehicle is always greater than the energy that can be recovered through regenerative braking due to thermal and mechanical losses. Therefore, if you start driving on a flat road, you'll create sufficient space in the battery as soon as you move.

That last 3% charges slower, and BYD gains a competitive advantage by moving the goalposts to say that 97% counts as "full" because reasons.

It does mean that a car charged on top of a mountain can still do one pedal driving on the way down. Consistency of how the car responds to pedal inputs is a safety feature.