[Calc] Battery % Remaining at End of Trip Depending on Speed and Distance

Naturally I love to nerd out with my new Prius Prime 2017!
I've been driving it for the past 2 months from work to home, starting fully charged, to test out the usual 12.4 mile drive after work everyday with no AC, varying my highway speeds between 55-85 mph.

so I've been trying to calculate how much energy is loss to Air Resistance, kinetic energy brake regeneration, and friction from motor/moving parts losses.
At high speeds between above 60 mph, the % battery remaining calculated on my excel sheet is stupid accurate, but at low speeds below 60 mph, the error increases exponentially;
I'm assuming motor/moving parts losses increases exponentially with lower speeds; I have it calculated relative to total energy output relative to Kinetic energy and air resistance energy outputs, which is incorrect.

Does anyone know how what to add to this excel sheet to make it more accurate to real life?

Thank you, and have fun!

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