by Jack Rosebro
Virginia’s Fairfax County Department of Vehicle Services, which already has conventional hybrids in its fleet, took delivery last week of a Toyota Prius PHEV conversion from Hymotion of Toronto, Canada. The vehicle is part of the county’s regular motor pool, and is available to employees traveling on county business.
The Hymotion L5 conversion kit features a 5 kWh lithium-ion battery pack that supplements the OEM NiMH battery pack in the Prius.
The PHEV system recharges from the engine and regenerative braking during operation and from the power grid when the vehicle is parked and plugged in. Once the PHEV battery is depleted, the vehicle resumes normal operation using the factory battery. While the PHEV battery is in use, the OEM battery fuel gage indicates its status.
Fairfax County’s Board of Supervisors voted in June to join Plug-In Partners (earlier post), a nationwide initiative to encourage automakers to develop and produce plug-ins. According to James Gorby, director of the county’s Department of Vehicle Services, more than half the cars in the United States travel less than 25 miles on most days.
Hymotion’s engineers completed the conversion on the evening of Tuesday, 28 November. Dave DuVal of Fairfax County drove the vehicle to attend the Electric Drive Transportation Association conference in Washington, DC Wednesday and Thursday.
With some highway and some city miles, the Prius display shows that with 94 miles driven, the car has averaged 77.9 mpg, starting on its third battery discharge. We like it so far!—Dave DuVal
Hymotion claims that the L5 pack can double the fuel efficiency of the Prius, pushing it to more than 100 mpg in combined city/highway driving, depending upon the actual drive cycle.