Hymotion battery installed !!!

Hymotion battery installed

Hymotion battery installed

Today was the big day for my Toyota Prius. A brand new Hymotion battery system was installed in my brand new 2009 Toyota Prius. I have only had about 1/2 of a charge to drive around in, so I don’t have a lot of experience with the improvements yet. But I am already impressed.

I rode along with the technician at The Green Car Company for the test drive. This consisted of a 10 mile drive around Bellevue Washington. The goal of the test drive was to verify that the Toyota Prius could average over 99.9 mpg, which is the maximum that the Prius computer will show on the display screen. In order to know the true mpg, I need to get a trip computer that goes over 100+ mpg.

With two big guys in the Toyota Prius, it passed the test easily. 10 miles at over 99.9 mpg with about 1/2 of the battery charged up.

From my brief experience today, I believe that an upgraded Hymotion Toyota Prius will be able to do between 20 to 25 miles in pure electric mode at speeds of 38 mph or less. It will take more testing to verify the actual pure EV range.

From what I have read from others, at highway speeds of 60 mph using cruise control, the battery should last for 50 to 55 miles and provide 100+ mpg average fuel consumption. Then once the Hymotion battery is empty, the Prius should revert back to standard Toyota Prius performance and do the typical 50 mpg after that.

It takes 5 or 6 hours to recharge on a standard outlet. 5 kwh at 8 cents per kwh = about 40 cents to recharge the battery. Our local electric grid is about 70% hydro, so that makes the Pacific Northwest an ideal region for this technology.

I will have more data and some videos soon. My ScanGauge II trip computer has been ordered. That will enable me to track the performance statistics above 100+ mpg.



  1. When you’re driving EV, how does the car feel? Is having only the electric power make sluggish acceleration? Do you feel the need to “tromp” on it to accelerate normally with other traffic?
    I’d assume that if more power is needed while in EV, and you do tromp on it, the gas engine kicks in and you have full power to pass or whatever the situation requires.

    Thanks for sharing the information!

  2. You have to accelerate a bit easy. If you stomp the acceleration, it will use gasoline. But there is a lot more play in the pedal compared to a stock Prius. In normal city stop and go traffic, you can stay in pure EV mode with normal Hymotion acceleration.

    It is rock solid to stay in EV mode up until 32 mph. At 33 mph or higher, there are many variables that can trigger the ICE to engage.

    At highway speeds of 55 mph, my trip computer tells me that the RPMs are at idle of around 950 to 1,100 RPMs. I have read that at 55 mph, 75% of the energy is coming from the Hymotion battery and 25% is from the gas engine. At 75 mph it is the reverse. My trip computer (ScanGauge II) is typically showing me 150+ mpg at 55 mph.

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