Prius hackers plug their cars in at night - get 100 MPG Marc Hedlund 02 Apr 2005

26 comments Latest by Cinnamon

NY Times: Hybrid-Car Tinkerers Scoff at No-Plug-In Rule - great story about Prius hackers getting huge gas mileage by plugging their cars into the electrical grid overnight:

Plug-in hybrid prototypes have been around for several years, but the idea of modifying a Prius stemmed from the curiosity of some Prius owners in the United States, Mr. Kramer said. They were aroused by a mysterious unmarked button on their Prius and discovered that in Priuses sold in Europe and Japan, the button allows the car to drive for a mile in electric-only mode. Mr. Hermance said the feature was disabled in Priuses sold in the United States because of complications it would have created in emissions-testing rules.
Mr. Kramer said "a bunch of engineers reverse-engineered it in the United States and figured out how to hack it."

26 comments so far (Jump to latest)

Brad 02 Apr 05

In a region like, say, the Pacific Northwest, where most electricity is produced without emissions (i.e., hydro), plugging in your Prius at night may be a good thing for the environment. But more than half the electricity in the United States is still produced by coal, so in some parts of the country your plugged-in Prius will have some pretty dirty emissions associated with it.

Also, I wonder how the economics of it work out…electricity isn’t free…how much does it cost to charge a Prius by plugging it in overnight versus charging it the usual way (through the little gasoline motor inside)?

Brad 02 Apr 05

Duh, I see that Dan Becker says the same thing in the NY Times article, should have read that first!

Anyway, the other thing that I’ve always wondered about the Prius — the article quotes an owner as saying that he gets 40-45 mpg in his Prius. That’s no better than a Toyota Echo, which costs more than $10,000 less. Hey, if you want to do something for the environment and can afford a Prius, why not just buy an Echo and donate the $10,000 to an environmental group or the Democratic Party?

Steven Andrew Miller 02 Apr 05

Toyota Echo, which costs more than $10,000 less. Hey, if you want to do something for the environment and can afford a Prius, why not just buy an Echo and donate the $10,000 to an environmental group or the Democratic Party?

I have read several times that there are more than a few hybrids that are less expensive and more readily available than the Prius, but they just do not sell as well. The problem with the other cars is that they do not “look” like hybrids. The Civic Hybrid for example looks like a normal Civic. It is a status thing. In fact, I think it is the exact polar opposite of people who drive H2s around. “Look at me, I’m _____ the environment”

Marc Hedlund 02 Apr 05

Brad, I definitely agree with the point you make, but note this line from the article:

For power companies, the notion of people plugging in cars overnight represents not only a new way to make money, but the vehicles would also draw power mostly during off hours which would improve efficiency, because power plants cannot simply shut down at night as demand diminishes.

I don’t know enough about energy production to say whether, today, a lot less coal is burned at night than during the day, and whether this hack, spread widely enough, would change that significantly. I do think, though, that having the alternative available is a good thing. Maybe the pollution from one centralized energy source would be lower than that from all the cars that would otherwise be driving on gas.

I was more enamored with this story because of its hacker ethic, though. “Here’s this unlabelled button — what does it do?”

Brad 02 Apr 05

Well, coal is usually used on the baseload plants (those that run all the time, rather than those that are called into service to help meet peak loads), so I don’t think it’s going to reduce emissions in that sense.

But anyway, it’s not a big issue at this point because there aren’t enough Priuses or people who care enough to try the hack to have an effect!

huphtur 02 Apr 05
Echo == 41MPG
Prius == 51MPG

Joe B. 02 Apr 05

I own a Toyota truck, and while in the service department one day a lady came in yelling at the top of her lungs because she *never* gets above 45mpg… ever. After she left the room, I heard the Toyota service people say “This is the worste thing Toyota could have done for that car… claim those number, it never happens”. I heard them talking about the same “line” they tell all the irrate prius owners… has something to do with getting above a certain MPH or something and being in the right “mode” before you start seeing the real benefits. An echo does sound like a better option if your real goal is to spend less on gas and help the enviroment. Maybe if they put one of those nifty screens in the echo with all the cars’ vital statistics people would go for them more? :)

Dan Boland 03 Apr 05

I actually drive a two-door 2002 Toyota Echo. When I bought it, I had four criteria:

1) Good gas mileage
2) Inexpensive
3) Small
4) Won’t fall apart in no time flat

The Echo was the perfect fit for me. The Prius is a beautiful car, but if I were to get a hybrid (which I might actually do eventually), I would get the Civic Hybrid. I can’t comment on highway mileage because I don’t do much long distance driving, but city mileage varies from 25 to 33 MPG.

But do you guys remember the Geo Metro? It claimed to get 59 MPG highway. My sister had the first model from 1989 (drove it for 13 years, too), and while the gas mileage was excellent, it only ever topped out in the low to mid 40s.

Michael 03 Apr 05

I saw a british car show, top gear, where the reviewer concluded that a VW Lupo diesel was far better for the envoironment.

I don’t know if they sell the lupo in USA, but they claim it has a mileage of 27 km per litre (roughly 63 mpg) when driving in the city and 33 km/l (77 mpg) on the highway.

Caleb 03 Apr 05

SmartCar (substitutable for other diesel engine car) + Bio-diesel = yessssss.

what if someone hacked out the gas engine of the prius, replacing it with a diesel, and ran it on bio-diesel…

Now that would be hawt

Brad Pauly 04 Apr 05

The EPA is responsible for the estimated mpg of a car. It was recently in the news that their estimates come from tests under optimal condition in a controlled environment. When people get out on the road the cars don’t perform anywhere near the estimates and people are pissed. The EPA is apparently considering changes for its tests.

I owned a Jetta TDI for a couple of years and it got around 50 mpg on the highway. Loved it.

eric 04 Apr 05

did you guys make changes to you stylesheet? this is the first time in a while that your content div wasn’t smooshed to the left, in Opera. awesome.

Lee Dale 04 Apr 05

If I were to purchase a fuel-economy centric car, I can tell you that I would definitely purchase a Prius over an Echo or any other existing options.

It has nothing to do with status, it has to do with space. The Prius is a mid-size car and has substantially more cargo space than, say, a Honda Civic or Toyota Echo. In Canada, we like to fit our hockey equipment in the trunk, not shove it in the back seat. ;-)

Darrel 04 Apr 05

”+ Bio-diesel”

The problem with a lot of biodiesel (like ethanol) is that it actually takes more oil to produce the fuel than you get out of it. Bio-Diesel, at least for now, is just yet another pork-barrel farm subsidy. Now, if we’re talking those ‘recycled McD’s fryer greese’ cars, well, there’s something to that… ;o)

Brad 04 Apr 05

The Matrix gets amazingly good fuel economy (the Canadian version is rated around 45 mpg) and has more cargo space than the Echo, and it’s still more than $10,000 cheaper than the Prius. I think the Matrix has as much or more cargo space than the Prius; I’ve been car-shopping lately and have checked them both out.

I’m not bashing the Prius, I think it’s great that people are buying hybrid cars and helping to push the technology forward. But from a purely environmental perspective, the Prius doesn’t perform much better in real life than the Echo or Matrix. The only real reasons to buy a Prius are 1) it’s cool and 2) you’re supporting the development of hybrids.

Oh and one note on those Volkswagen TDIs — diesel can give you incredible fuel economy, but it’s still not considered a “green” choice because of the particulate emissions. Even the newest “clean” diesels emit too many particulates to get good environmental ratings. Particulates have been strongly linked to heart disease and cancer, and a significant portion of those diseases in urban areas may be due to diesel emissions (mainly from trucks and buses, though cars don’t help).

Eamon 04 Apr 05

Ugh. Regarding Prius versus corolla/echo/elantra/accord/horse-and-buggy/segway: we’ve had this conversation before. And again. Anyway, let me summarize:

  • Those oft-quoted “misleading” mpg numbers are the EPA’s numbers, not Toyota’s. In a weird twist, Toyota’s hands are tied here: they are mandated by law to post the EPA’s numbers, and can not substitute numbers from their own testing. This is obviously a good thing: you wouldn’t want Hummer posting things like “Now 40* mpg! (* indicates highway, tail wind, in neutral, falling off a cliff)”.
  • Most of the mpg backlash came after Consumer Reports noted that their real-world testing of the Prius and the Civic hybrid did not match the EPA numbers. However, what’s often not cited is that it is a rarity that the EPA numbers ever match the CR numbers. CR also pointed out that the highway numbers were remarkably close, and although their city driving mpg of 35 was much lower than the EPA estimate of 47, it was still one of the best ever recorded in their history.
  • Fuel economy isn’t the end-all-be-all of green living. Total emissions is a key factor, too, and this is clearly where the Prius outshines its competition. They even made up a new category for the vehicle: the hilariously named “Super Ultra Low” standard. For comparisons, see’s side-by-side comparisons and the EPA’s Green Vehicle Guide. The Echo, for instance, puts out a full 15% more greenhouse emissions than the Prius.

Anyway, a personal anecdote: when Toyota announced that the Prius would be coming to the United States, I was concerned about the maintenance and longevity of the vehicle, so I made an appointment with a local dealer to talk with their master mechanic for a while. He told me that Toyota had flown him to a special week-long intensive introduction to the Prius. On the very first day, an engineer held up a small Ziploc bag of dirt and said, “This bag contains the entire particulate emissions of ten years of driving the Prius.” That made my mechanic a convert, and it made me one too. I [heart] my Prius.

All that said, I take the bus more often than not.

smoothj 04 Apr 05

From a purely environmental perspective, the Prius doesn’t perform much better in real life than the Echo or Matrix. The only real reasons to buy a Prius are 1) it’s cool and 2) you’re supporting the development of hybrids.

I’d think that you have to add the 40-60% less tailpipe emissions from the Prius to that list. The average car (even the Echo and the Matrix) produces about 13,600 pounds of carbon dioxide a year. Any reduction in that has to be good …

MrBlank 04 Apr 05

“The problem with the other cars is that they do not “look” like hybrids.”
Yuck! The Prius is U-G-L-Y. I’d go with a Honda just because it doesn’t look like a hybrid.

My questions are: How many miles do you get out of a hybrid before it craps out? less than 200,000 miles? What do you do with the dead batteries? If they don’t last 200,000 miles, then what do you do with the waste from the batteries? Even though you aren’t dumping as much waste into the air, how much extra would you be adding to the landfill? How much extra energy would it take to recycle the stuff? Is it really that much better than an efficient gas-powered car?

Brad 04 Apr 05

I’d think that you have to add the 40-60% less tailpipe emissions from the Prius to that list. The average car (even the Echo and the Matrix) produces about 13,600 pounds of carbon dioxide a year. Any reduction in that has to be good …

Sorry to be nitpicky, but the reduced tailpipe emissions you’re citing (relative to other high-economy cars) are not carbon dioxide, they’re the other stuff like NOx and particulates. The amount of carbon dioxide emitted by a car is directly proportional to its fuel economy; emissions controls have no effect on CO2 (in fact they may increase CO2 emissions since gasoline is burned less efficiently than it would be otherwise).

Eamon 04 Apr 05

I don’t know, MrBlank. How about doing at least a tiny bit of research instead of just phrasing your speculation as questions?

Never mind, I’ll do it for you. One, the entire hybrid system in the Prius is warrantied to 100,000 miles. Two, the batteries are considered “non-hazardous waste” and can be safely disposed as normal municipal garbage. And three, Toyota has had a battery recycling program since 1998 and even offers a “bounty” to dealers to ensure that the batteries aren’t just thrown away.

So yes, it is. HTH.

MrBlank 04 Apr 05

Thanks, Eamon, I liked those links. Saved me a lot of time. :-P

PS: How else do you phrase speculation if you want an answer?

One of several Steves 04 Apr 05

Eamon, thanks for the bullet points. Every thing I wanted to say is captured right there.

One other thing to note: as appealing as diesel is for fuel economy, the stuff is still pretty filthy in terms of emissions. It’s gotten a lot better, but it’s still very sooty and still cranks out a lot of sulphur. As Brad notes, that invites its own host of problems.

Dan Boland 04 Apr 05

Lee Dale: I don’t know, I was surprised by the amount of trunk space in the Echo. It had more than my old car, a Pontiac Grand Am (a much larger car). Though I’ll admit that your hockey equipment still wouldn’t fit. ;D

Eamon: You’re exactly right that fuel economy and emissions are equally important in determining a car’s environmental record. But fuel economy is the only one that’s relevant to the average person’s daily life. Idealistically, I would drive the car with the best combination of the two, but realistically, I’m going to pick better gas mileage over better emissions every time because you can have the former for not a lot of money (e.g. the Echo), whereas having the latter requires a lot more green up front.

Now I’m sure someone can go dig up a bunch of information about how high emissions cost the country billions of dollars a day or something equally horrifying from a financial standpoint. And I wouldn’t doubt that for a second, to be honest with you. But the average person can gauge how much gas he/she needs to spend and can afford to spend to get around. That’s something tangible I can put in my budget.

sloan 04 Apr 05

In the end, going to something like zero emission hydrogen based cars is the way to go. I haven’t seen a study, but I would have to imagine that it is much more cost effective to clean up power plants than each and every car individually. Coal can be cleaned up greatly, but recent laws have actually made it dirtier than in years past and mining for coal has had restrictions removed, resulting in more environmentally devastating practices. Over a third of greenhouse gas pollution in the US comes from cars, hybrids are a great middle ground for the foreseeable future. I prefer the Prius over the Honda’s because it is a 5 door. But all of them are priced too highly and the tax break was reduced to $1500 from $2500 (if I remember correctly) so the price hike to be greener is hard to take.

Felix Kramer 05 Apr 05

I appreciate all the thoughtful comments. I urge you to read our 3-page Fact Sheet, found in PDF form at and in text form at

We answer the Q, How Much Cleaner than a Gasoline Car is a PHEV Charged from the Dirty (Coal) Grid? at

Paybacks from green cars are complicated, because so much of the benefit goes to society and the world, not to the individual. Here’s another way to think about it: when you hear a person shells out big bucks for a V8 instead of a V6, or leather seats, do you ask, “What’s the payback?” Of course not. It’s a “Feature.” Plug-in hybrids offer the feature of car that’s fun and better for the world. If gas prices go up, or you get a solar photovoltaic rooftop, congratulations, you’ll clean up personally a bit more.

And to keep things lively, we’re linking to this blog at

Cinnamon 06 Apr 05

My partner and I purchased a Prius a little over a year ago. During the winter we averaged 46-50 mpg in the city and during the summer it was more like 50-54 in the city. There are tricks to driving. It turned my partner from a brake and gas quickly guy to more of an easygoing, spend a lot of time coasting guy. How you drive really does affect the gas mileage.

We chose the Prius over the Echo because it doesn’t have enough space for all the stuff I need to take to craft shows, or for our road trips. We chose the Prius over the Civic because the gas mileage was better, the air bags seemed better, the sound system was much, much better, the seats were more comfortable for my slightly-short frame, and our 6-foot plus friends fit in it easier. The sales person at Toyota was also much more informed and less pushy than the person we dealt with at Honda. It doesn’t hurt that we think it looks cool and that it came in better colors and that it is bluetooth enabled.

Post a comment

(HTML is allowed)