It depends on settings, state of charge and temperature of the batterypack. On normal it stars a slow regen as soon as you let go of the "gas". And brakes are only deployed if you hit the brakes. However if you already have a full battery (very rare) or the battery is cold (very often in cold winter) the battery cant absorb the charge, so regen is disabled. This means the car brakes very differently, with or without regen, but this is also indicates on the dash.