Back in 2006 when I first started writing professionally about cars, plug-in cars were just starting to make a comeback to the marketplace with the reveal of the Tesla Roadster. At the time, a number of fans of the second-generation Toyota Prius wanted in on the action and started adding bigger battery packs to turn them into plug-in hybrids. A combination of wanting to grease that squeaky wheel and plug-in vehicle mandates from the state of California eventually led Toyota to produce a plug-in variant of the third-gen Prius and I recently got to spend a week driving one.
Between the do-it-yourselfers and a handful of conversion companies that popped up, word began to spread that you could double the mileage of a Prius from 50 mpg to more than 100 mpg. When the production Prius PHV launched almost three years ago, the EPA officially rated it at 95 MPGe in “electric” mode and 50 mpg in regular hybrid mode, but how does it measure up in the real world?
The reality, as is so often the case when we talk about vehicles capable of running on electrons is complicated. Compared to other mainstream plug-in hybrids, the Prius powertrain is somewhat less powerful. Ford uses a 118-horsepower electric motor in the C-Max and Fusion hybrids while the Prius only has 80-horsepower to work with. The Fords also carry a 7.6-kilowatt-hour lithium ion battery pack while the Prius only has 4.4-kWh of electron storage capacity.
The result is that on the EPA driving cycle, the Prius doesn’t get an all-electric driving range because the engine must occasionally run to complete the test. However, the Prius is able to go about 11 miles in blended operation with occasional engine running, especially if it’s cold and you turn the heat on.
Since it debuted, even the non-plug version of the third-gen Prius has had an EV mode button that would try to keep the engine off and use what ever recovered energy was stored in the battery. My experience with that was that you needed an extremely light touch on the accelerator to squeeze about a mile of electric operation out of it without triggering the gas engine.
In the Prius PHV, with a full charge of the battery which takes about three hours on 110-volts, I found it actually quite easy to drive electrically using moderate acceleration that wouldn’t totally irritate the other drivers around you. Since I’m not partial to freezing my backside when the temperatures are in the 20s or teens, I set the automatic climate control to 68 degrees which caused the engine to run for a couple minutes after starting to generate some heat and then shut off in around town driving.
As an aside, the Prius PHV Advanced I drove was equipped with heated seats but it was a couple of days before I realized that the switches were actually mounted in the storage bin below the center console, outside of any normal visibility or comfortable reach. Not really a good ergonomic choice by the Toyota designers.
Overall it’s actually not that hard to drive the Prius PHV completely on electricity for about 10 miles or so, enough to run some errands and pick up groceries. I was definitely able to keep the fuel consumption graph up in the 100 mpg range for most of my local driving. The limited motor power of the Prius means it can only operate without the engine at speeds up to 62 mph, before switching to hybrid drive at highway speeds. With the cold early December weather we had around here and early sunsets that meant lights on a lot of the time.
Seat heater switches are hidden in the storage space below the center console
Combine that with the extra couple of hundred pounds the PHV is constantly lugging around in the back and both city and highway fuel economy in hybrid mode were generally about 40-42 mpg. An excellent result for most cars, but less than the 50 mpg most Prius owners generally expect.
One of the displays available in the instrument cluster is a graph that shows lifetime percentage of electric driving vs hybrid operation. The Chevy Volt has a similar display and on average, it will show about two-thirds all-electric operation and one-third hybrid. This press-fleet Prius showed a mere five percent of its several thousand accumulated miles being electric only.
Aside from the silent driving around town, the Prius PHV is pretty much like any other Prius albeit with a slightly more lumbering feel thanks to the extra mass. I’ve never been particularly fond of the long, skinny central instrument cluster of the Prius. I prefer a set of clear, round gauges directly in front of me. The Advanced model does have a small heads up display which helps and thankfully Toyota has incorporated a HUD that doesn’t disappear when you wear polarized sunglasses.
It was surprisingly easy to stay in electric mode around town
Prius has never had the most nimble handling or supple ride quality and this example was no different. It wasn’t objectionable by any means, but the Prius has never been the sort of car that inspires owners to just get in go for a drive to nowhere in particular which is probably a good thing given its green image. If you want something for a random drive down a twisty country road there are choices elsewhere. If you want efficient functionality, Toyota has you covered.
Since I last drove a Prius Toyota has introduced it’s Entune infotainment system. Unlike the Ford AppLink approach of letting developers add hooks to smartphone apps to enable drivers to control them through the head unit of voice commands, Toyota integrates a small selection of apps into a custom Entune app. Entune includes the ubiquitous Pandora, Yelp, OpenTable, Microsoft Bing search and a handful of others.
After linking the Entune app to your accounts for these services, you can use them through the Prius touchscreen although voice commands are very limited. For example in Pandora you can create a station with a voice command but you have to touch the list on the screen to select existing channels. Strangely, in order to trigger voice control you have to touch the microphone icon on the screen rather than the voice button on the steering wheel. The button on the wheel only works for navigation and hands-free phone calls.
Entune uses the connection from your smartphone to update itself
Since the Prius doesn’t have an embedded cellular radio, when you launch Apps function, the in-vehicle component of Entune uses your phone to connect to Toyota’s servers and check for an update. If an update is available, the system asks before downloading and you’ll probably want to do this at home with your phone on wifi. Since the bluetooth phone connection to the car is much slower than a typical wifi connection, the update available for this loaner took about 15 minutes to download and install.
So is it worth opting for the plug-in version over a conventional Prius? Frankly, with a base price nearly $6,000 more than the most affordable non-plug model, it’s pretty hard to justify the plug and bigger battery. The limited electric range and the need to run the engine generate heat means that once you add in the cost of electricity, you won’t actually be saving much in around-town driving. If you do any significant amount of highway driving your EV mode driving will be further limited.
If your highway commuting is limited and you really want zero emission driving, you can get a base Nissan Leaf S for nearly $1,000 less and get triple the Prius’ plug-in tax credit at $7,500. Even stepping up to the mid-level Leaf SV and adding the cost of a 240-volt home charger will be cheaper than the entry Prius PHV. The Advanced model I drove stickered at $38,900. Through November, Toyota had sold 12,772 PHVs and 113,977 conventional models in 2014 so it seems most customers have been doing the same math.
Click here for full specifications of the Toyota Prius PHV
