I often wondered, if in a close-call situation regarding remaining range, would it be better to slow-down or stop at a Level-2 charger. I decided to do some quick math, realizing that there are lots of variables that I didn't consider, but generally speaking, it seems slowing down is about equal. Here's the math (or maths if you're from the UK): Let's assume an S75D can go 225 miles at 75MPH. Sound about right? That would be 3 miles per kWh (225miles/75kWh). At 55MPH, the car should be able to go 335 miles which would be 4.46 miles per kWh (335miles/75kWh). Let's say you have 75 miles remaining on your trip but only 17kWh of battery left. Going 75MPH would take one hour to arrive, but would require 25kWh of energy (75miles/3miles per kWh). You would have an 8kWh deficit. At a 30A/6kW Level-2 charger, those 8kWh would take about 1.33hrs (8kWh/6kW). Going 55MPH would require 16.8kWh (75miles/4.46miles per kWh) but would take 1.36hrs to get there (75miles/55MPH). Therefore, it seems that slowing-down from 75MPH to 55MPH in this case would be about equal, notwithstanding the extra time to pull over, plug-in and get-back on course. As much as this was a specific set of circumstances, I think it generally applies to most situations. If you can still make it by slowing down a reasonable amount, it pays to do that vs. stopping at a standard Level-2 charger. Of course, if you need to stop anyway, then charging is a better option, but if time optimization is paramount, it looks like a tie. Moral of the story, if you need more range, slow-down, unless there's a Supercharger en route. But, if you don't want to slow down, stopping at a Level-2 is about equal.