I am getting about 1-1.5 mpg better using power mode than normal mode. This seems to be about two mpg better when using the a/c. The car is also so responsive in power mode. Why is this? My next test is to see if power mode will give me better mpg while cruising the highway with the cruise set at 75mph. Any thoughts on why power mode is getting my better mpgs? Maybe I should always use power mode!
The theory is you get up to speed faster using ICE rather than waste battery energy by babying the pedal. Same concept as pulse and gliding.
Others have posted the same experiences and as 32 said, that's the general concnesus as to why. BTW, if your Prius is a 2010 it's a Prius III. (just reading your profile) The three designation began (a little too late to avoid confusion) with MY 2011's.
Personally, I think the mods should change all the II through V to Two through Five for the Gen III. There's absolutely no difference in how we call them and it's less confusing that way. It's confusing enough when we'll have the Prius v and its associated numeral trims.
I saw similar results when I first used PWR mode and for the reason that 32k gives. Since PWR mode is not a default mode on powerup I just chose to leave it in NORMAL mode, no mode indication. The only difference between ECO, NORMAL and PWR modes is the remapping of the accelerator pedal input in the first half of travel. So, you can get the same response in NORMAL mode but you will just need to move the accelerator pedal a little more than PWR. I still use the PWR mode when I need to accelerate quicker than normal like on a highway entrance ramp, from a stop light in order to change lanes, etc. I will switch to PWR mode now and then just to know that Prius can get up and go when it needs to.
In a nutshell, many drivers erroneously assume that granny driving is the key to good mileage, and because of this accelerate too slowly and tend to use electric propulsion more than necessary. Power mode makes it harder to do this, so for this sort of driver, Power mode can produce better mileage. Tom