I feel this whole MPGe figure is a joke since prices of electricity and gas fluctuate. For me I can't plugin at home and the charpoints near me are .20 kw/h and gas is just under $3. Based on my simple calculations I found that running on electricity or gas to give me a similar cost within fractions of .05 per mile. when i see 199 mpg average when running in EV mode this is meaningless to me, as I know from my calculations that the EV mileage should be very similar to the Hybrid mileage of 55 depending on driver and conditions. So to calculate a more accurate average mpg I think it would be necessary to allow the user to input their cost per gallon of fuel and electricity rate per kwh into the system. Then the car can calculate if running on electricity offers an advantage or deficit to gas in cost per mile and adjust the average MPG accordingly. For instance if running on electricity the same distance costs half of the same distance on hybrid. Then the EV miles should show an average of 110 if the hybrid 55 is used as a baseline. The only way that we should ever see 199mpg would be if electricity was 1/4 the cost, which is very possible years in the future, but it would be nice to have this accurate for current month.
miles per gallon has nothing to do with cost. 199 mpg is meaningless. it could be 999 or 9 million. when using ev, mpg does not apply. miles per kWh would though.
Fair enough. Then we should just get rid of the mpg average altogether and have a guage that does cost per mile then To blend a mileage rating for EV and hybrid, I think we have to use a common factor. Also does anyone know the miles per kw/h for the prius prime? Or what is the size of the EV portion of the battery? I can run some math with those numbers. From another thread someone charged their prime with a full hybrid but depleted EV portion and it took 6.41 kwh to fully charge. So it would be close to 4 miles per kw/h VS 54 miles per gallon of gas. So back to my example using .20 cost per kw/h: Take the .2 and divide by the 4 miles and you get .05 per mile. For the $3 gallon / 54 = .055 per mile. If the car could have these imputs it could then blend a true cost per mile using whatever combination of EV vs hybird miles that were put on the car. For those of you able to charge at home for say .11 per kwh you would be seeing a cost of EV of only .0275 per mile. So if you drove half on EV and half hybrid your combined mpg should be something closer to 80.