Pre-Production Review: Toyota Prius Plug-In Take Two

Alex L. Dykes
by Alex L. Dykes

Every time I drive a hybrid – EVERY time – someone asks: “so where do you plug it in?” It’s as if more than 10 years of hybrid sales in the USA have gone by without the public knowing that a hybrid is not an electric car. Finally, however, Toyota has announced there will be a hybrid Prius on sale in the US where the answer isn’t “um, you don’t, the gas goes in over there.” Now the answer will be: “you plug it in up here and put gas in back there.” Yep, the 2012 Plug-In Prius is coming, so be prepared for blank stares as passers-by try to process the information. Toyota tossed us the keys for a week’s drive in a pre-production version so we could see what the hype is all about.

In 2010 Toyota kicked off their plug-in program by sending 150 Prius-Plus-Cords to the USA. All are powder blue, all destined for the press, commercial or government fleet use. Toyota has been cagey about how much the 2012 plug-in will cost and exactly when it will appear in showrooms, but the online rumor mill tells us the premium will be $3,000-$5,000 and we should see them before the year is over. The price difference doesn’t buy you bigger motors or fancier interiors; the only real difference lies in the battery pack under the carpet in the trunk and the software under the hood.

A regular Prius uses a 1.3kWh nickel metal hydride (NiMH) battery pack, the same technology that powered my first 1990s cell phone and my Apple Newton, the plug-in Prius uses lithium-ion cells, the same thing that’s in your trendy iPad2. Of course trendy batteries cost a pretty-penny, but they also pack a bigger punch: capacity is up from 1.3kWh to 5.2 kWh in the plug-in. Rather than popping in a single larger battery, the plug-in actually uses three packs all hidden under the cargo area. There is one small pack with a similar capacity to the regular Prius and two larger packs with a capacity of approximately 2kWh each. When charged, the Prius will first discharge the two larger packs, and when the car drops out of EV mode it uses just the smaller pack and runs just like a regular Prius.

In addition to the capacity bump, the new pack allows a higher discharge rate than the NiMH pack and that’s important. What does this mean in English to a regular Joe? It means that the new Prius can operate electric-only in every-day driving, even up hills at speeds up to about 50 MPH while accelerating normally and up to about 70MPH if you are ginger on the pedal. The cost of this electric-only fun will run you some $0.50-0.60 depending on your electric rates and, unlike a Leaf it won’t take you all day to charge going from empty to full in 3.5 hours on 110V or 1.6 hours on 220V.

Inside, the Prius is the same as always: the dash still wears wavy-patterned hard plastic, the 1980s modern disco-dash is still in the center, and the overall theme is still focused on weight reduction. Indeed the only interior difference is the EV icon on the dash, a charger under the passenger seat, and the bigger battery in the trunk. Despite the changes, the plug-in Prius weighs only slightly more than the standard model as lithium batteries weigh less per KW than the nickel units, so even though capacity is up 400%, weight is only up 100lbs or so.

OK you say; it has a bigger battery, so what? Well, with that bigger battery you store electricity that was (hopefully) generated more cleanly than the Prius’ onboard gasoline engine can muster. If you live on the right or left coasts, using your household electricity would (supposedly) result in lower CO2 emissions, if you are into that sort of thing. Since you’re adding electric mojo to the mix, your gasoline usage will of course be reduced on your daily commute. Here’s where the disclaimer “your mileage may vary” has never been more appropriate. ABC News Polls claimed in the results of a 2005 survey that the average American commutes only 16 miles a day. Our own informal Facebook poll revealed similarly short commutes for our followers. I however commute 109 miles a day (because I’m insane). Because of my commute, my first reaction to the 14-mile range was: it wouldn’t make enough of a difference. 14-miles? Who cares? Right? Well, here’s how it worked out for me:

Starting with a full tank of gasoline and a charged battery, I made it from home at 1,100ft above sea-level to the 2,250ft mountain pass on the fumes of electrons and then started downhill. First thing I noticed on my way down to sea-level on the other side is; the larger battery pack in the plug-in provided greater capacity for regenerative braking, a real benefit on my terrain as a regular Prius fills it’s battery to capacity before I am 1/3 of the way down. At 20 miles from home my commute-route turns from mountain terrain to flat highway. By this time, the engine had run for brief moments with negligible fuel consumption resulting in some 130 MPG average. This is where most Americans would end their day. At 30-miles my average had dropped from the high triple digits to a (still) lofty 96 MPG. At 40 miles, my average dropped to 93 MPG, 50-miles came in at 85mpg, and by the time I reached work (54 miles later) my economy dipped to 83.4MPG. That’s the point of the larger battery.

Just to verify my mileage calculations were grounded in reality and not based on some optimistic ECU, I topped off the Prius at the gas station around the corner from the office and my informal calculations bore out the ECU with an estimated 82.5 MPG. (Gas-pump mileage calculations on such a small quantity of fuel are difficult, so keep that in mind) How does this compare to a normal Prius? On my same journey in a regular Prius I averaged 52.9MPG, and the plug-in Prius with a discharged battery averaged 55.6. Why the difference? The plug-in’s larger battery pack seems to take greater advantage of regenerative braking on my mountainous commute.

My round-trip commute average, only charging at home resulted in an average of 72MPG meaning my commute of 109-miles required only 1.5 gallons of gasoline. I tested a regular Prius on the same commute and it required 2.1-gallons for the same journey. Meaning for me, it would take 5-8 years to pay off with the expected price premium of $3,000-$5,000. Is it worth it? Let us know in the comment section. As fate would have it, two weeks after the Plug-in-Prius, GM loaned me a Volt for a few days. With a full battery charge and an EV range of 40-miles, the Volt averaged a startlingly low MPG average of 48 on this same 109-mile trip primarily because the economy after the battery ran out averaged a paltry 30.1MPG. Comparisons to the Leaf are tricky since the Leaf is electric only, I’ll let you draw your own conlusions.

Out on the road, the plug-in handles just like a regular Prius: the low rolling resistance tires deliver moderate road noise and precious little grip in the twisties. If you have ever wondered why hybrid drivers drive so slow around corners, it’s the rubber to blame. The steering is numb and a bit over-boosted, body roll is average and acceleration is leisurely. The Prius’ mission is efficiency rather than driving pleasure, so keep that in mind before you trade-in your 335i. The one area the plug-in differs from the regular Prius is acceleration. When the battery is fully charged you have to exceed approximately 3/4 throttle to involve the gasoline engine. Even in mountainous terrain gentle-to-average throttle is met with only the light whine of the electric motor, an experience you can only get in a plug-in or fully-electric vehicle. If you treat the pedal gently, it is possible to break 70-MPH electric only, but that does mean you have to piss off everyone behind you on the freeway on-ramp. If however you drive it like a normal Prius, then somewhere around 45-50 MPH the gasoline engine will turn on (this is accelerating at a normal pace to freeway speeds). Unlike a normal Prius which will use the engine for the majority of the locomotion, the plug-in lets the engine more-or-less idle when accelerating gently using the plug-in battery for most of the oomph. Contrasting back to the Volt, flooring a Volt with a charged battery doesn’t involve the engine [Ed: unless it’s cold out or you’re over a certain speed or the Volt’s algorithms only know what else].

Since this is a pre-production car, we will have to wait until Toyota releases official pricing and produces a production car to assess final range figures and posit an opinion about whether or not it will be “worth it”. However on the face of things it looks to be a must better proposition than the Chevy Volt providing you some obvious mileage benefits and a possibly plausible pay-off date, something the Volt has trouble achieving. If you live in one of the 15 states where the Prius plug-in will be available, stay tuned for a full review when the production models start rolling off the line.

Toyota provided the vehicle, insurance and fuel for this review.

Not a fan of our Facebook page? Too bad. For our facebook peeps, here’s what you wanted to know: Eric R: nope, not possible. Brian J: Yep, I have to say I did feel green-superior while driving it, probably because of the “plugin” stickers on the side. Jamie F: It is more practical than a Leaf, but less “whiz-bang.”

Fuel economy average over 870 miles: 59.9

Percent of time in EV mode: 16%

Performance statistics as tested:

0-30: 3.42 seconds

0-60: 10.35 seconds (“regular” Prius: 9.5 Seconds)

¼ Mile: 17.7sec @ 77.9 MPH










Alex L. Dykes
Alex L. Dykes

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  • Michal1980 Michal1980 on Jul 14, 2011

    Why do you push people to facebook? Your ad are on this site, not face book, or would you rather just kill ttac, and just be on facebook?

  • Carlson Fan Carlson Fan on Jul 14, 2011

    You simply cannot define "payback" on any vehicle that helps the US become energy dependant by running on domestically produced electricty vesus imported oil. Electric cars are not the "smoking gun" to solving all our energy issues but they are definitely a piece of the puzzle. Hooray for cars like the Volt, Leaf and PI Prius.

    • Wsn Wsn on Jul 15, 2011

      Exactly, a coal fueled plant in Western Virginia may be cleaner overall than fighter jets flying and bombing middle-east. Not to mention the jobs.

  • SaulTigh When I was young in the late 80's one of my friends had the "cool dad." You know the guy, first to buy a Betamax and a C-band satellite dish. Couple of stand up arcade games in the den. Bought my friend an Atari 2600 as soon as they came out. He had two of these crap heaps. One that only ran half the time and one for parts in the yard. My middle school brain though he was the most awesome dad ever, buying us pizza and letting us watch R rated movies recorded on free HBO weekend. At the time I though he was much better than my boring father.Now with adult hindsight, I now know he was "dad who should have taken better care of his family" and not had so many toys.
  • Dave Has to be Indy 500. Many more leaders and front passes than NASCAR, and Monaco is unwatchable with the inability to pass on that circuit.
  • Jeff How did the discussion get from an article about a 56 billion dollar pay package for Elon Musk to a proposal to charge a per mile tax on EVs in California or paying increase registration on vehicles to make up for lost gas tax revenue? I thought such a discussion would better fit Matt's Gas Wars series.
  • Master Baiter Both people who bought ID.4s will be interested in this post.
  • Urlik Not a single memorable thing happened in the big three races this weekend IMHO.
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