When do I need to charge my EV? Do I need to charge my EV to 100%?

No, you don’t need to charge your EV to 100%.  

If the charge flow rate, meaning the power delivered by the charger, is high at the start of the session, it will drop throughout the charging session.  

Similarly, the slower the charge flow rate, the more constant the energy recovery by the EV, and the more it will drop when the charging level has reached its maximum limit, which is around 80%. 

It is therefore recommended that you charge your EV to between 20% and 80%. When the battery level reaches 80%, charging speed drops considerably and the time needed to go from 80% to 100% will be similar to the time needed to go from 20% to 80%. 

For more details on the factors impacting your charging session, this article may interest you.