An customer is not always aware with how much power his/her (new) electric vehicle can be charged.

To give proper advice about this, you can take a look at the EV-Database website.
Here you can see what the maximum charging capacity is per electric vehicle (for 1- or 3-phase).

Example:



When you are not able to find the exact model of your car, please also check the Archive on the bottom of the page.

 
You can then advise the customer what type of charging station is most suitable for this specific vehicle type. 
Please take into account the available power at the local electricity connection.