The MPH/kW display causes some confusion, because: MPH is an average over the entire charge session, calculated as (miles/kWh * (kWh added during session)) / (charge time in hours)) kW hours displayed is your current, instantaneous power draw. On a Model 3, you can approximate "instantaneous" MPH by multiplying kW by 4 (250Wh/mile; on an S or X, use 3; 333Wh/mi). At the beginning of a charge session, you'll notice the *4 relationship is pretty close (250kW = 1000MPH). As the charge session continues and the charge rate tapers, the *4 relationship breaks down. Let's say I plug in my S at around 10% with the charge slider set to 100%. Initially I will draw around 118kW, and the MPH will show around 354MPH (118*3). Assume it takes 1 hour to hit 100%. After 1 hour, I will have added (100%-10%) * 255 miles, or 230 miles (I'm using 255 instead of the original capacity of 265, since my battery has degraded a bit). Just before charging completes, my MPH will show ~230MPH, but my charge rate will be down to around 2kW.