Putting a Plug-In Hybrid (PHEV) Car to the Test

By dancurranjr On April 21st, 2009

plug-in-hybrid-phevThe most surprising thing about driving a plug-in hybrid was how ordinary it felt.

Experts say plug-in hybrids are likely to be the Next Big Thing in automobile technology. I wanted to see how they work in the real world.

This would be a test: I’m a driver who never looks under the hood, hates spending money on cars and/or gasoline and can’t handle any automotive problem more complicated than adding Drygas to the tank.

First came a neon-green 2006 Toyota Prius emblazoned with the Green Mountain Power emblem. It’s one of two the electric utility added to its fleet, spending $10,000-a-car to have a stock Prius hybrid modified by adding a big second battery. (Solar panels on the utility’s roof generate enough electricity to recharge the batteries.)

My first reaction when I turned on the car was like that of many new Prius owners: This thing isn’t working.

No hum of a gasoline engine. Dead silence at every stop sign. I kept reaching for the starter button, assuming the car had stalled. Lesson One: An electric motor is silent.

Unlike stock Priuses, the GMP car supposedly can travel up to 40 miles on electric power alone. For someone who lives in the center city, as I do, that could mean a lot of nearly all-electric driving.

But in the four days I drove the car, it never came close to 40 miles of all-electric driving.

I could watch the car’s computer monitor as the charge in the added battery dropped quickly. On day one, the battery ran out at about 17 miles. The car smoothly switched to running on its gasoline engine, assisted by the stock Prius battery. I was back to 50 miles a gallon instead of 100.

Learning the tricks

As I learned the tricks of driving a hybrid, the battery took me somewhat longer distances. To keep the gasoline engine off, my right foot began to push more slowly on the gas pedal. Any sudden acceleration switched on the gasoline engine. As I drove Shelburne Road, I would push down gently on the accelerator, then let up so the car would glide.

The Prius’ dashboard computer screen registered every little change, telling me my miles-per-gallon had plummeted from 99 mpg to just 12 when I tried to accelerate really fast.

Jim Harding, a Green Mountain College professor who drove an identical plug-in Prius last year as part of a research project, found his driving style also changed.

“You become hyper-aware of how you are using the vehicle because the feedback is so immediate and detailed. I found myself not pressing the accelerator as quickly as I would have, and coasting through turns,” he told me.

Recharging the add-on battery was a snap. At bedtime each night, I plugged one end of an extension cord into an outlet on the back wall of our house. The other end fit a plug on the back end of the Prius. Red tail lights went on, alerting me that the battery was charging.

When I came out in the morning, I unplugged and drove off.

One morning I drove around Burlington, looking for places I could recharge during the day. The charging stations at City Market and the intersection of Church and Main worked fine. The three outdoor plugs on the waterfront were dead. Later, I learned that a number of Burlington parking garages have at least one plug-in station.

Vermont-made plug-in

After I returned the GMP hybrid, I borrowed a second one from EVermont, a nonprofit consortium that studies electric vehicles.

This was definitely a homemade version. It had little quirks. The gasoline engine cycled off and on at stop signs, for no reason I could discern. The dashboard warning light was permanently on.

“The car is still a work in progress,” research director Harold Garabedian said.

Instead of adding a battery to the off-the-lot Prius, EVermont pulled out the car’s original battery and replaced it with one capable of being recharged from the electric grid.

This battery was bigger than the one in the GMP Prius and it showed. I drove the car 30 miles one afternoon and still had juice in the battery. Garabedian said he’s gone as far as 50 miles relying mostly on the electric motor.

Paradoxically, this car got better mileage on the highway than in the city, the opposite of most hybrids. That’s apparently because EVermont is still working out the bugs that turn on the gasoline engine at slow speeds, when it isn’t needed.

Once on the open road, the electric motor carried me most of the way to Charlotte. My average miles per gallon soared to 74.3.

Paying the price

I loved driving both cars. They were quiet, I wasn’t burning much fossil fuel, my carbon footprint shrank, and I was using a cheaper fuel than gasoline.

Charging the GMP Prius took 4½ hours one night. A special meter told me the car had drawn 5.23 kilowatt-hours of electricity.

A call to Burlington Electric Department informed me that I pay 12.5 cents per kilowatt hour for my electricity (not including the customer service charge, which I pay however much juice I draw).

Cost to power the Prius for a day: 65 cents, plus a few tablespoons of gasoline.

Of course, that doesn’t include what it would cost me — north of $30,000 — to acquire a plug-in Prius.

That’s the only reason I’m back today, driving my ordinary Honda Civic.

SOURCE: Burlington Free Press

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