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Toyota Prius MPG-Real World Numbers

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Comments

  • pathstar1pathstar1 Posts: 1,015
    You didn't mention where you are, but the cold of winter really gives the Prius a mileage hit. Once it warms up the mileage is really good. I'm probably in a colder place than you and I'm getting 6.5 l/100 km or 36 MPG US. Similar trip lengths. In warmer weather (spring, summer, and fall) I get 4.4 l/100 km or 53 MPG.

    Use full brake when stopped. There is only about 2 Amps fed from the battery if you don't press fully, but it's still wasted energy. Also, use "D", not "B".
    Accelerate normally from lights. It's the slowing down where you can save fuel. Try to anticipate the light and slow a long way before you get there. Don't worry about the nuts who will pull around you so they can wait at the light before you get there. Just keep telling yourself they will be the first at the accident! ;) Once you get up to speed try to "feather" the throttle to just maintain your speed. That will allow the car to save you some fuel (it may even shut down the engine from time to time once it has reached full warmup).

    Make sure you have lots of air in your tires. Most of us put in more than the door sticker calls for. I use 40 PSI front and 38 PSI rear. This actually also improves the tire to road traction, yet decreases drag. Check the tires at least once a month.

    Be patient. It takes most people a few months to learn how to drive economically. Use your MFD (multifunction display) to help you to learn what actions save fuel.
  • Yeah, I've been doing all those driving techniques you mentioned, including the coasting and gliding. Thats how I am managing 55 MPG on the highway at least. Unfortunately 85% of my driving is in the city :( I live in the Boston area.

    Thanks for confirming my thoughts on the stop light braking. I guess I'll just have to wait until it warms up a bit before I'll see decent mileage on my commute.

    Its good to know you are getting a 50% boost in MPG during the summer. Gives me hope I might get a little better mileage in the summer at least. Where do they get 48 city / 45 highway from anyhow? I can't comprehend how anyone could be getting better mileage in the city given the disparity I'm seeing?
  • BTW, how well does the MFD display really work? When I first start driving, its all downhill, so my display shows just blue arrows feeding the battery, but my MPG is showing like 9...? How can I be getting 9 MPG if my gas engine isn't even producing any energy?
  • scottc3scottc3 Posts: 109
    I think going downhill you MPG should be 99.9 mpg.. not 9. If it's not showing this, does it ever show 99.9? or in the high 90's? If not, you may have a problem wtih the display. Don't panic here, just have it checked or compare to others. Are you accelerating going down hill? If so, try coasting - foot not on the gas, and see what it reads.

    sc
  • pathstar1pathstar1 Posts: 1,015
    The mileage is low going down the hill because the engine is running on a warmup cycle, using enriched fuel mix. It only runs at 1280 RPM, but it still burns fuel. This is the big hit on mileage in winter. Once my car warms up it seems to get almost the same mileage as it does in summer, so you can see how big a hit the warmup cycle is. You have to get the coolant up past 60C before the car will go to "stage 4", so it will shutdown the ICE when it isn't using it. Idling will not do this, I have to drive perhaps a mile before I see this coolant temp (I'm using a "Scangauge II" - an OBDII reader, to monitor the temp, battery voltage -12V, and two other parameters). If you only drove longer commutes you would see better average mileage, as the poor warmup mileage would be spread over more good warm running mileage numbers.

    As for MFD accuracy, each car seems to be a little different. My car seems to read a little low on mileage most of the time. However, it's difficult to tell because you can't consistently fill the fuel tank each time, so your checks on mileage are not consistent. Others have reported the MFD reading to be about 10% optimistic. Isn't that why they say "YMMV"? ;)
  • Thanks for the reply. I figured it had something to do with the engine warm-up... I guess my short commute (about 7.5 miles) through a myriad of stop lights means I'm not going to get the same benefit from a Prius the average person would. Especially in the winter time :( Ah well, 30 MPG is still better then what I used to get. Now if I could just use more then 10 gallons of that 12 gallon tank, I might actually be able to get a reasonable range ;)

    I also noted that the engine will frequently turn on (after engine warm-up) while I'm going down hill with the break applied for the soul purpose of charging the battery once it reaches blue. This happens at around 60-70% of total battery capacity. Is this just Toyota being obnoxiously conservative again? I mean, I'd rather let the battery use a bit more energy. If I do hit the highway it ramps up for full green pretty quick anyhow. Once it hits blue, it doesn't matter how I drive or at what speed, the gas engine turns on an frequently does nothing more then charge the battery...
  • Hello everyone,

    I just bought a Prius two weeks ago. I have to say I've been disappointed with the mileage so far. But I like the car. By my own calculations (first tank) I'm averaging about 33. I live in Dallas. In the morning's it's a bit cold now so I have noticed gas mileage is lower than in the evening, where I come out from an underground garage at work (usually close to 60 degrees). So now I know. My commute is 15 miles, 1st mile local, next 12 highway, next 2 local.

    pathstar1:

    1) My engine charges when it is high blue also. Hate it.
    2) Never have hit full green yet
    3) I have confirmed coasting always helps, even when the engine is cold. When the engine is warm 99.9 on the display is very possible (I turned the display off after realizing the readings were not accurate. Also too distracting.)
    4) I do need to check my air pressure (thanks to someone who mentioned it above) and I will hold the brake down at lights from now on.
    5) Today after going to 1 bar I added 3.3 gallons ($10) and the bars suddenly jumped to 6. Still very puzzled by the display.
    6) I did accelerate suddenly for a bit, re-read the manual said it was a no-no. Stopped that.
    7) My MFD is telling me 41.5, but it did get reset 20 miles ago. Currently I'm at 380 miles. Will let everyone know what I average when I fill up later this evening.

    Nice forum. Thanks for the advice.
    newpriusowner
  • ces1938ces1938 Posts: 61
    Hey guys, relax... if there is anything that I have learned in my 70 years and after many new cars of all kinds, you may as well accept what your car is getting and that is it... the fuel estimates are just that, some where in the ball park and usually way below... they are just lying about it and they get away with... really that simple sorry but that is the way it is... if you accept it than you wont be so frustrated.... in the 50 years I have many new cars and not one ever come close to what the gas mileage predicted... so buy what you want and enjoy it and don't even pay anything to gas mileage and you will be happy... One thing I have learned it does not matter a whole lot of what you buy they all use a lot of gas, so get one that is fun to drive and let it go at that.... good luck folks... :) :shades:
  • So I filled up the tank. I was able to add 5.2 gallons before the gas pump stopped. So I've added 8.5 gallons so far. I restarted the mileage at 390 miles. We'll see how far it goes.

    ces, good advice. I'm not old enough to know that (this is my first car) so I want to enjoy every aspect of it.

    newpriusowner
  • pathstar1pathstar1 Posts: 1,015
    There are a few mis-conceptions floating around about exactly -why- the Prius engine is running. Note that the "engine" is the gasoline powered device, and the "motors" are the electric "motor/generators".

    1. The engine runs to warm up the cat. or to keep the cat warm, which must be kept quite warm to function properly. This is "job 1" for a Prius - keep emissions very low.
    2. The engine runs to keep itself warm, so it can stay in the "stage 4" mode, where it can shut off the engine if it doesn't need it. It sounds funny that it has to run the ICE so it can shut it off, but there it is. In the summer this is not an issue.
    3. The engine will run if the coolant drops below about 63C if you have the heater on.
    4. -IF- the traction battery gets low in charge (below 40%) the engine runs to charge it back up to around 60% charge. The battery is run from an absolute low of about 30%, but usually 40%, to a high of 80% charge. This is to ensure the battery will last a long time. Taking the battery below or above these "setpoints" will increase the chances of fully draining or over charging individual cells, which would damage them. Note that these percentages are not the full green bar/empty red bar indications of the SOC indicator. Those take the set points into account, so full green is actually about 80% charge, and one or no red bars is actually 30-40% charge.

    Also keep in mind -you- don't actually control this, the car does. You CAN "influence" the SOC as well as when the engine runs. If you use "Climate control" and leave it in "auto", when you want the engine to not run turn it off on the steering wheel. Then, if you take off from a light turn it back on again. I personally don't bother, but you can slightly improve your mileage by doing this. I'd rather have non-misted windows and be nice and warm. :)
  • pathstar1,

    Thanks for the info. :)

    I definitely didn't know the battery stays in a range of 40-80%. This makes sense from an engineering standpoint. I don't leave my climate control on auto usually.

    What's SOC stand for by the way? Also what are the 4 stages the Prius goes through? Which stage is the best?

    Learning and confused newpriusowner
  • kdhspyderkdhspyder Posts: 7,160
    ONe of the biggest drains on all vehicles, hybrid or not, is having to accelerate from a dead stop. Overcoming the inertia of standing still is a HUGE waste of fuel. There is no way to obviate Newton's Laws.

    I did a similar test on the streets of NYC where I used to live and work. Going across town from stop light to stop light to stop light I was only able to achieve about 35-40 mpg, this with a fully warmed up vehicle. However going south along one of the major Avenues at a constant 25 mph I was able to achieve 70-80 mpg!!!!!! Same trip, same vehicle, same city, same everything excluding the stops.

    This is one of the few unknown limitations on driving no matter the vehicle. A good solution would be to replan your route if possible to avoid the stops.

    ***65,000 mi on my 2005 ( nowhere near carbot's 2004 ) with a calculated fuel economy of 47.9 mpg ( 2.09 gpc ) as per GH database.

    Regarding the fuel capacity questions, dont worry. I'm pretty sure that no one explained to you that you have two gas tanks in your Prius???? Huh?

    Actually in order to reduce/eliminate evaporative emissions there is a fuel bladder inside your tank. When the vehicle is new the bladder is still stiff and not expanded to its full capacity. This is doubly true during cold weather when the bladder might be stiffer than normal in the cold AMs. As the weater warms up and the bladder breaks in you will find that as you get down to one bar you will put in about 9.0-9.5 gal when the last bar begins flashing. This is intentional, not only with the Prius but with all Toyota's ( e.g. the light on the Camry will come on when you've used about 16 o/o 18.5 gal ).

    As carbot noted you can drive a good 50 mi safely before you must refill.
  • pathstar1pathstar1 Posts: 1,015
    SOC is "state of charge". It's calculated by the cars computers (power in - power out) not assumed by looking at the voltage.

    Funny, I looked up -again- the document on the warm up stages, and it appears there are actually five. It's complex and appears at:

    http://www.techno-fandom.org/~hobbit/cars/five-stages.txt

    These are enthusiast named states of operation. I don't believe Toyota uses this description.

    Note that the "EV" (electric vehicle) switch is not installed in the North American models, though the programming to operate the car using it is. If you do want to install this switch, you can purchase a "stock" Japanese one. You will void your battery warranty though. What this switch does is extend the parameters for electric only operation. The car will still start the engine and use it if it needs to.

    Stage 4 is the preferred one to be in, as the car is fully warmed up and will have the best chance of getting good mileage.
  • scottc3scottc3 Posts: 109
    Today I hit 1 bar left on the gas gauge. Not wanting to push this, and to check how much gas I had left, I filled up. I put n 8.756 gallons and drove 430 miles. This equates to 49.1 mpg with just over 3 gallons left in the tank. Now I know I can easily drive 100 miles when I hit 1 bar and was pleased with the 49 mpg for the 1st tank.

    sc
  • pathstar1pathstar1 Posts: 1,015
    You're making a dangerous assumption. The fuel tank capacity changes due to the bladder being more or less "streatchy". This is one of the reasons Prius owners run out of gas more than -any-other-car-! I've seen reports from owners who have only gone 40 mi. on the last pip.

    So don't get mad at anyone but yourself if you run out. The car gives you lots of warning.

    I must be of Swiss heritage. I fill up after the car gets below 1/2 tank on the gauge. ;)
  • kdhspyderkdhspyder Posts: 7,160
    LOL.. I'm in that group but I'm aware of my personal predilictions. I tend to push that last bar....but I've been rewarded with the 'triangle of death' 4 times.
  • I am a new Prius owner. Purchased a 08 package #6 last Tuesday. I typically drive 40-50k miles per yr and spend most of that time on a highway. in just 4 days I have put almost 800 miles on it. Live in MN and dealer tank gave me about 34 mpg, second tank gave me 43.8 mpg. Currently on third tank and reading about 38mpg (but it is also currently -15F temps).

    Could you please explain to me what the various stages of the ICE are? You mentioned Stage 4 mode to shut the engine off if not required.

    Also, should you normally be able to show a battery full charge (all bars)? I haven't seen that happen even once on mine. The best I can get is 1 bar away and only for about 2-3 minutes. However,I do need to bring it back to the dealer as when I'm coasting the blue arrows go from the tires to the motor to the battery, but it doesn't change color when braking. (I test drove another one that does change color under braking and talking to the dealer on the phone they said the other 08's change color also.)

    Anyone out there that does alot of highway driving (70% at 70-75mph) that could tell me what kind of MPG they are getting would be much appreciated.

    Thank you all.
  • kdhspyderkdhspyder Posts: 7,160
    I don't do as much as you do but I put about 35K on mine annually. It too is about 70% highway but the max speed I'm allowed is aobut 65 most of the time.

    Lifetime over 65000 miles I'm at 47.9 mpg....but here are the caveats....from a post that I made in the Camry hybrid forum last year here

    Factors affecting your FE ( and everyone else's also, btw ) in decending order of importance...
    1) Towing anything is a huge penalty possibly as much as a 50% reduction in FE
    2) Lots of weight in the vehicle, passengers cargo etc. ( EPA tests are done empty ) deduct up to 20% from your 'Norm'
    3) Short trips under 10 min - deduct 20% from your 'Norm'
    4) Snow, Rain, sleet - deduct 15%
    5) Strong head wind - deduct 10%
    6) Cold weather - deduct 5 - 10%
    7) High speed driving 0ver 70 mph - deduct 5 - 10%
    8) Many starts from a dead stop ( going from stop sign to stop sign to stop sign ) - deduct 5 - 10%
    9) Terrain - fortunately 'what goes up..' usually this balances out on a RT
    10) Winter fuel - deduct 2 - 5%
    11) Low tire pressure - ? How low

    In your type of driving you probably won't run into a lot of these like many starts and stops and towing and short trips. But cold weather, wind and slippery surfaces will have a huge cumulative effect of as much as maybe 10-25% reduction from your best results. Pathstar1 who lives in CA would be able to give you a better perspective on these factors.

    Afriend who posts here also is at 175,000+ in just over 4 yrs but in the Middle Atlantic region where it's milder. I believe that lifetime he's around 47 mpg also.
  • pathstar1pathstar1 Posts: 1,015
    I posted the URL for the "stages" in post 483 of this discussion.

    Many Prius owners have posted they have only seen green bars after a few months. It -may- take the car that long to be sure of the full capacity of the battery, self calibration so to speak, or it -may- be (my choice) that the NiMH battery needs some charge/discharge before it begins to work fully. At any rate, I didn't see -any- green bars until 2 months after purchase. Usually you won't reach full green unless you descend a long hill, such as a mountain pass, though it is possible if you are really economical in the city. You won't see green on level highway, or at least I don't. The car tries to keep the SOC (state of charge) at about 60%, blue bars. I doubt there is anything wrong with your car.

    Once the car is nice and warm, you can get up to 50 MPG on the highway, but that's a summer figure. The faster you go, the worse the mileage. You probably loose 2 MPG to the ethanol in the fuel, another 2 MPG to winter added friction (oil viscosity and stiffer tires). Then there is added loss from heavy winter winds, and snow pushing. Be aware there is a breakin period during which you will not achieve the good mileage figures. This includes breaking in the tires. It seems to take 2000 - 5000 mi. You should be able to achieve 45 MPG in the summer and 40 MPG in the winter with no problem, once broken in. Many do better with practice. The winter warm-up cycle is very hard on mileage. I notice that once my car is fully warm, in winter, it starts to get nearly the same mileage as it did in the summer, but the average really suffers. My summer average, once I learned and the car was broken in was getting up around 53 MPG US. Right now it's averaging around 40 MPG! City only in winter.
  • eprupiseprupis Posts: 30
    I filled my tank (8 gallons) with 10% ethanol for the first time. Here in the flat SC low country, I average 53 mpg consistently. This time I averaged 50.5mpg with no change in route or driving technique. I then made it my business to fill the next tank with pure gasoline and I immediately saw my mpg go back to 53. Although 10% ethanol produces a 4% mileage penalty, the price at the pump is no lower than stations without ethanol diluted fuel. Considering the effect of ethanol production on the cost of grains and meat, and the impact of its production on the environment, I think the promotion of ethanol is a huge mistake.
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