Prius Plug-In: Tweaked for Efficiency

May 15 2005 – Vol.10 No.8

PRIUS PLUG-IN:TWEAKED FOR EFFICIENCY.

What’s Toyota to do? Shade tree mechanics are turning its poster child for fuel-efficiency into a star-of-the-show. Will Toyota reengineer its hybrid technology to plug-in capability and sell a car that gets over a 100 miles per gallon?

Unless they can find a legitimate excuse not to, they may have to.

The word is out - even in the mainstream press - that an extra battery pack tucked away under the hatch of a stock Prius, along with some additional wiring, can drastically improve the car’s already great fuel economy. Advocates of plug-in hybrids will certainly protest if Toyota ignores the improvement.

And, of course, if Toyota shifted gears from hybrids to plug-in hybrid electric vehicles (PHEV) other companies would soon follow suit. They’d have to, and in short order. A car that achieved better than 100 miles per gallon would certainly make headlines and sales; sales that some struggling car companies probably can’t afford to lose.

In the American Tour de Sol a Toyota Prius, modified into a PHEV, achieved 102 miles per gallon on a 150-mile run with the help of nine kilowatt hours of electricity needed to recharge the vehicle’s batteries when it was resting. Those nine kilowatt hours would cost less than a dollar if purchased from the power grid.

Do the quick math. About 1.5 gallons of gas at say $2.20 for the 150 mile trip equals $3.30, plus the dollar for electricity totals $4.30. Aside from a significant reduction in emissions, that’s really inexpensive driving, if, of course, you don’t include the premium cost for the stock hybrid vehicle and its modifications to PHEV.

Driving costs drop even more as fuel efficiency increases to 125 miles per gallon, or more, for daily commutes of 50-60 miles when trips are made mostly on battery power.

The modified Prius PHEV included Valence Technology’s Saphion lithium-ion batteries with electronics and modifications by EnergyCS. EnergyCS has partnered with Clean-Tech LLC to develop and commercialize retrofit conversion kits to turn some hybrids into plug-in hybrids. (Possibly available in 2006.)

(Because of the differences in hybrid design Toyota’s and Ford’s hybrid technology can be modified, Honda’s can’t. Honda hybrids can’t run on battery power alone.)

The Tour de Sol is an annual rally of cars built by manufacturers, individuals, and students, that are near or at zero emissions and nearing total independence from oil. Visit the Tour de Sol at http://www.tourdesol.org/ Valence at http://www.valence.com/ EnergyCS at http://www.energycs.com/ and EDrive Systems at http://www.edrivesystems.com/ .