Dr. Rangelove (or "How I Learned to Stop Pumping and Love the Plug")

The fact that Toyota has invested the time and engineering to develop a plug-in version of the much-loved Prius is fantastic. That they will be performing long-term, real-world tests with fleets over the next year is impressive. That they gave me one to drive around for a week is downright silly and careless. Oh well, two out of three ain't bad. Let's get this straight from the beginning: I have been driving my 2004 Prius for six years. I know that car inside and out. Literally. I chose to not purchase a 2010, Gen3 Prius when they were initially introduced. I have made it very clear that my next car would come with a charging cable. Because of my decision, I had very limited experience with a Gen3 Prius. So as you can imagine, I had a double learning curve to overcome and often had to check with my Gen3 Prius owning friends to determine if a characteristic was native to the Prius or new to the PHV. Keep in mind that the Prius PHV I drove is a pre-production, test unit. There are rumors, hopes and even a few non-disclosed confirmations that the functionality and setup of the final production vehicle will be different in a few key ways. I will review and explain the vehicle I drove. In a few years, we can look back and determine the final details Toyota tweaked as a result of the feedback they received. Overview: First, let's discuss the functionality of the plug-in and how it's engineered. From the very beginning of Prius, owners have asked whether they could plug it in at night to charge the hybrid battery. The intent was not to have an EV range but merely to start each trip with a full state of charge. The Prius PHV takes that idea one step further by replacing the single Nickel-Metal Hydride battery pack with three Lithium Ion packs. When the car is plugged in, all three packs charge to full capacity in three hours. Using an energy meter, I was able to determine that this charge requires a consistent 3.66 kWh of electricity. This full charge provides 14 miles of Electric Vehicle (EV) range. When those 14 miles are over and the EV battery packs are depleted, the PHV operates as a regular Gen3 Prius. That's pretty much the nuts and bolts. Now to break it down. Most current Prius owners realize that the Prius battery is never fully charged or fully depleted; the battery charge indicator does not actually show 0 to 100 percent (more like 40 to 60). By limiting the state of charge to this comfortable mid-range, Toyota is able to extend the life of the battery. There is currently no information to determine whether they have implemented the same approach in the PHV. For that reason, references to a full state of charge might actually mean that it's “full as far as you know.” Likewise, when the batteries show depletion, they might be depleted only as far as Toyota allows. This approach represents a trade-off between battery life and vehicle weight because it forces the car to carry around “extra” battery storage capacity that will never be fully charged nor fully discharged. The three-hour charge time is pretty quick and convenient. I found a few different scenarios in which three hours seemed just about perfect. One is after the morning commute. I could charge the car when I arrived at work and be full by lunch. If we went out, I could top off before returning home. If there were multiple plug-in vehicles where I work, we could charge in shifts. This way, one plug could serve multiple people throughout the day. A similar approach is simply not easy or possible with a four or five hour charge time. Additionally, if I felt uncomfortable having my car plugged in outdoors overnight, I could plug it in when I arrived home and be fully charged by bedtime. This way I could remove the plug and not leave it dangling from the car overnight. It's not that I don't trust the neighborhood kids, it's just that – yeah, I don't trust the neighborhood kids. There was no rewiring or dedicated wiring required for the PHV. I was able to plug it directly into the plug already in my garage. The only consideration is that it should be a dedicated plug; attempting to charge the car while making toast and drying your hair all on the same circuit is a bad idea. I consistently showed 3.66 or 3.67 kilowatt hours (kWh) on the energy meter. I pay 8.8 cents per kWh. This means that each charge cost me approximately 32 cents. Those 32 cents propelled the car 14 miles. My Gen2 Prius averages about 60 miles per gallon; the same 14 miles would require 0.23 gallons of gasoline. At $3.00 per gallon, that's 69 cents, slightly more than twice the cost of the electricity. Of course, as gasoline gets more expensive, plug-in vehicles become more appealing. It is at this point that it's worthwhile to mention that driving the PHV is not free. That sounds pretty obvious, doesn't it? But I would not be surprised if in a year or so someone makes the speculation that any plug-in vehicle could save a driver $1,200 per year if they currently drive 12,000 miles at 30 mpg averaging $3.00 per gallon. In my experience, even if you were able to drive the entire 12,000 miles purely on EV, you would still be paying $600 for the charge. In the grand scheme of things, the shock of the higher electric bills would be offset by the reduced gasoline expenses but it's still not free. And about that 14 mile range. When coworkers asked about the range, many scoffed at “only” 14 miles. With the Leaf touching 100 miles, the Volt estimating 40 miles and even the Tesla Roadster reaching 250 miles, 14 seems like an exercise in underachievement. However, I have to wonder how many people would exceed those 14 miles on a regular basis. I drove errands around town purely on EV. Here in the Chicagoland area, a daily commute exceeding 14 miles is average but unless I'm mistaken, most of the people in the world do not live in Chicago. I would love to see hard figures for the average daily drive around the world. The Prius is, after all, a global vehicle and should not be scrutinized exclusively on how it will be driven in the car-dependent United States. I exceeded those 14 miles every day with my regular commute. And that's where it's important to remember that this is not an electric vehicle: this is a plug-in hybrid. After 14 miles, you are driving a standard Gen3 Prius with the 55+ mpg capabilities it provides. This is truly a combination of the best of both worlds. But this is also a combination of the worst of both worlds. When driving in EV mode, the PHV is lugging around several hundred pounds of internal combustion engine and all the transmission, exhaust system and everything else that goes with it. No doubt this amount of dead weight negatively affects the EV range. Once the EV battery packs are fully depleted, the PHV is lugging around an estimated 300 pounds of dead batteries. No doubt this amount of dead weight negatively affects the hybrid mileage. So in a true case of equivalent exchange, you benefit and suffer from both technologies. Driving: Well, pre-driving, actually. The PHV uses the SAE_J1772 plug. This is an industry standard agreed upon by major automobile manufacturers. This is, of course, a very good thing. Unlike cellular phones that require a different charger for practically every phone, EVs and plug-in vehicles have a standard. This means that ideally you should be able to pull up to a charging station and plug right in. At least, that's the plan. My daily commute is 17.6 miles one-way. Pop quiz: this is farther than 14 miles. [ ] True [ ] False I got to see that “EV Range” deplete every day. It's like a ticking time bomb. As you drive, you see that number get smaller and smaller. At first, you accept it. Then it drops below ten and you say, “already?” You quickly add the trip distance to the EV number to see if it's really 14 miles. By the time you're finished with that, you're at 9 miles left. When you reach five miles left, you have a possessive sense of loss. After all, just a few minutes ago you had ten and before that, the pack was full. As I got more comfortable with the car, I became convinced that the average driver would probably see 14 miles of EV pretty consistently. Of course, your mileage may vary but I would guess that not by much. If you want more than 14 miles of EV, there are hypermiling techniques to gain an extra half mile, or mile or even two miles if you're good. This is where you turn that feeling of loss into a sense of pride. After all, most of us drive the identical commute every day. How fun it was to travel just a little farther this morning, to eek out another half-mile or even just one more block on EV before the engine had to engage. But it's not all fun and games. The PHV inherits a negative aspect of the standard Gen3 Prius: it is extremely difficult to “glide”. Like the Gen3, the PHV is either moving electricity from the battery to spin the electric motor or it's using the wheels to spin the electric motor to generate electricity and recharge the batteries. It's pretty much that binary, cut-n-dry. Compare this to the Gen2, which makes it possible for the driver to work the pedal in such a way as to disengage the electrical mechanisms. This allows the car to free-wheel or “glide” as it's called. This is the equivalent of putting the car in neutral and rolling. Without the ability to manually disengage the system, the driver is at the mercy of a constant drag on the system. I'm not saying that this causes the car to travel less than 14 miles on a charge; what I'm saying is that a good driver could routinely hit 16 miles if they had the ability to glide. Upon arrival at work, I would flip over to a new display Toyota has introduced for the PHV. This display shows the percent of your drive that was completed in EV mode and the percent driven in hybrid (HV) mode. At first, I felt that this screen was utterly useless. I mean, seriously, I have a full charge, it gives me 14 miles. Certainly whatever percent it shows me would be 14 miles. But that’s not what I found. When I started performing math against the numbers and percentages, I found that some days I was able to exceed 16 miles of EV whereas other days I was 15-point-something. On a day when I wasn’t trying to hypermile, I was just barely above 14 miles. This provided a new comparison model for hypermilers: how many miles were logged in EV mode. I’m still working out what other use this screen provides the average driver. For example, if you never exceed the EV range, you already know that you traveled 100% in EV. On the other extreme, for longer trips, the percentage of EV is very small and rounding errors are introduced. If I travelled 14% EV on a 100 miles trip, was it 13.5 miles or 14.4 miles? Should I care? Maybe if actual miles (with a decimal or two) were displayed instead of a percentage, I would feel better. One concern I had coming into the driving experience was that of engine warm-up. The standard Prius runs the engine to heat itself and the catalytic convertor. During EV driving, the engine is just sitting there at ambient temperature. This is where Toyota had some options. Option one was to completely deplete the EV batteries before engaging the engine. This way, the car could travel the whole 14 miles without burning even a drop of gasoline. They chose option two: start the warm-up cycle before the EV batteries are completely depleted. Specifically, when there are exactly 1.6 miles of EV range left, the engine engages and begins a warm-up cycle. At first, I was disappointed that I couldn't travel the entire 14 miles gas free. Then I realized that by starting the warm-up cycle, they are allowing the engine to warm-up at a light-load state. When the EV batteries are completely depleted, the engine is already at optimal operating temperature. It's a strategy that, in my opinion, was a good call. The PHV can operate exclusively on batteries up to 65 mph. Due to electrical motor sizing, this is the point at which the engine engages. The transition from EV to engine is fluid and almost undetectable. In fact, it was so subtle that the standard road noise nearly covered any indication of the switch. When operating in hybrid mode, the EV distance is not affected. Hybrid mode driving seems to pull energy exclusively from the hybrid battery pack and not from the plug-in packs. This means that if I wanted to drive on the interstate and have EV range left over when I exit, I could simply maintain a speed faster than 65mph the entire time. I'm not sure it was Toyota's intention to encourage speeding. A viable alternative to this would be the introduction of a button to override the EV driving. I have already heard the cries of potential buyers who do not want to deplete their pack in the first 14 miles because it makes more sense for them to use it at various locations spread over their drive. Accelerating from a stop is a very different experience to those accustomed to conventional cars. The most obvious is that there is no revving of an engine. There is no transmission shifting gears (Prius drivers forgot what this felt like years ago). What there is can be accurately called silent motion. Make no mistake: if you punch the pedal hard enough the engine will engage. So this proves that it is possible to force the engine on but it will shut off again with the first chance it gets. This is the interesting part of driving the PHV: rather than using the battery to supplement the power of the engine, the engine is there, if needed, to supplement the power of the batteries. When it's no longer needed, it will shut off. I found this very refreshing. I knew that I wasn't driving an EV but it felt as though I was most of the time. On the highway, the PHV is a very capable vehicle. Solid handling and able to nimbly move through traffic when needed. Interstate speeds were easily manageable, with passing abilities when needed. Much more so than my 2004. Not that I, uh, you know, fully tested interstate passing speeds or anything. Certainly not. ;-) As I mentioned, there are a total of three battery packs in the current PHV: two for plug-in range and one for hybrid driving. While it is possible to capture some regeneration while in EV mode, once the EV batteries are depleted, they physically disconnect from the drivetrain. The only way to recharge the plug-in packs – once depleted – is with a plug. This is unfortunate. My hope is that Toyota will change this setup with the production version. Ideally, a long downhill stretch would be able to recharge all three packs to provide additional miles of EV range or at least allow extended periods of stealth mode while in hybrid mode. How ironic it would be if those early Prius owners got their wish of a single pack, fully charged at the beginning of each day and fully rechargeable throughout the day. I personally exceed 65mpg in my Prius with its 6 year old battery and battery range; give me a battery pack capable of holding, say, ten miles of rechargeable EV and 150mpg wouldn't even be a challenge. I have to believe that Toyota considered the range of the PHV in comparison to the other vehicles coming to market. They had to know that a 14 mile range is currently the lowest. However, as I became familiar with the car, I began to think in terms of overall appeal. Sure, 14 miles is not that far, but a three-hour charge time from a straight 120v outlet is pretty sweet. Farther distances require larger batteries and batteries are expensive; their goal is to bring a car to market that people can use and afford. So I'm thinking that somewhere at Toyota Headquarters is a pie chart or perhaps a spider chart showing a balance between distance, charge time, weight and overall vehicle cost. Their goal, of course, is the sweet spot. Overall and Lasting Impressions: As I logged the mileage I was achieving, I became acutely aware of a huge gap in American vehicle rating: we have no current standardized system for gauging the efficiency of electric and plug-in vehicles. As I said earlier, I used 3.66 hWh of electricity to travel about 14 miles. Is this good? I simply don't know. How far will the Leaf travel on 3.66 kWh? Can it go farther or not? Which vehicle has the more efficient storage system and electric motors? I simply don't know and neither will the average consumer when they consider a vehicle that uses electricity for at least some of its propulsion. Reporting miles per gallon simply is not appropriate for the first 14 miles of PHV driving. A system of miles per kWh or similar electricity-based measurement will need to be established and agreed upon by manufacturers and built into the EPA's testing cycles. This is the only way consumers can know which system is the most efficient and the only way manufacturers can claim to have a better electrical system. By the time my experience with the car was over, I was just starting to view it as just another vehicle. As a friend once put it, “the go-pedal is on the right, the stop-pedal is on the left and when you move that wheel thingy the car changes direction.” That's it. As some consumers look to hybrids to prove to the world that they are a little different than the average driver, manufacturers must make sure the driving experience is as close to a conventional vehicle as possible. The adoption of a new technology rests on a manufacturer's ability to reduce or eliminate the learning curve. In this area, I think Toyota has a winner. The PHV that I drove seamlessly integrated the Prius that we all know and love with plug-in technology. Once I was able to get over my child-like giddiness for driving the car and enjoy it for the solid vehicle it is, I was able to appreciate the engineering that has clearly gone into it. As much as I appreciate the reduction in gas and oil consumption; as much as I like knowing that this is another step in the right direction of electric vehicles; as much as I believe Toyota has another winning vehicle coming to market in a couple years, I was absolutely underwhelmed by the whole EV experience. This is a car that anyone can drive with no need to understand how the charging cycles work, how the warm-up cycles activate, how the batteries are depleted and balanced or even when the engine is running or not. In the same way that the Prius made hybrid technology fashionable and available for the average driver, this Plug-in Prius will play its role, alongside other vehicles coming to market, to usher in the era of plug-in vehicles. This is truly an advanced technology vehicle that outshines even the Prius that came before it. But it is also a vehicle the mass market can grasp with no leap of faith or learning curve. In short, this is a car I would buy my mother. And she would love it. Sorry Mom. You're going to have to wait until 2012 when the PHV is expected to hit the showrooms.

 

You mean these things come with A/C?!

I only used the A/C on the one drive from Green Drive Expo and that was slightly more than 100 miles and I started with a nearly depleted EV pack on a drive that started with about ten miles of high-speed highway. Any drop in EV performance was not noticed. As far as I know, the Heat and A/C of the PHV is identical to the Gen3 Prius.

 

Remember that eye-crossing non-disclosure agreement Toyota gave us in Torrance?