While electric car batteries do not need to be fully discharged in order to “calibrate” them like many consumer electronics, allowing your electric car battery to regularly dip down to a low charge level can help prolong its overall lifespan.
This is because electric car batteries tend to degrade over time due to repeated charge/discharge cycles. Also, the available capacity of electric car batteries decreases with each cycle, so using the entire capacity of the battery helps maximize its full potential and decreases the rate of deterioration.
Therefore, it is generally a good idea to use all of your electric car’s battery before starting your charge cycle in order to maximize the battery’s longevity and performance. However you should always follow your EV’s owner’s manual advice first, each car’s charging requirement may vary by model and production year.