There have been many good questions as to which 'Mode' is the best to use. There is not an across the board best
to use. However the attached guide will offer a good understanding of how each one works and the conditions that may make it the best one to pick. As the driver you just need to know enough to decide which is best for your drive. It's good to understand because your drive conditions may change each time you get in the car.
Starting on page 11 it speaks of the different modes and as you read on explains in laymen's terms how and when to use the different ones.
While you can have a preference and use whichever one you like, reading and heeding
the instructions will give you the best economy for the driving conditions present for each driver.
Understanding how a PHEV is different from the previous hybrids will help a lot in knowing which mode (EV, HV, HV/Charge, or Sport) is best.
In short, this will work for most of us. If driving in municipalities where speeds are less than highway speeds and trip distance (round trip) will be less than 20 miles than EV is the most economical. If your distance is longer and/or highway speeds are involved than starting out in HV will run the ICE (internal combustion engine) enough to 'maintain' a high charge on the batteries. If you are traveling cross country for a few hundred miles, than when the battery condition falls below 50% you can select HV/Charge and the battery will come back up to slightly over 50% if you drive far enough. On a longer cross country drive your MPG will probably be in the mid-low 40's unless you drive over 70mph. If so, you'll get there slightly faster but it will use more gas.
Everyone has different driving conditions so a better understanding of the way the system is designed to work will offer the best economy for everyone. With the differences in drivers, routes, distance, and speeds, we will all get a different set of numbers but can operate the car to get best possible under each set of conditions.
I've owned three Lexus hybrids prior to the Clarity. I have 3800 miles on 'Watson' now and think this is the best design for the money currently available.
Comments are welcome.