The main difference between 7kW and 22kW is the charging speeds and how many lines of power are routed to each.

7kW is our single phase charger. It charges slower than 22kW but most homes will require this charger due to the power available through the switchboard. 

22kW is our three phase charger. Three phase chargers have the capability to charge at a faster rate than the single phase, however installing in the home is not available to everyone as this requires existing three-phase power setup. The design of the vehicle will determine how much power can be drawn from the charger regardless of how fast the AC charger is.