Mediocre MPG - normal or should I be concerned?

Draining and charging does not happen naturally - that's why you don't understand the suggestion. It is true that some recharging happens for free through regenerative braking, but even that is less efficient than not braking at all. It's a common misconception that the battery magically charges when the engine is running without adding any load, but it's not true. Every joule of energy in that battery you paid for, and paid for with gasoline.

Since you already understand the inherent losses I won't belabor them: burning gas to spin the generator to charge the battery to discharge the battery to spin a motor to power the wheels. Using EV mode for normal driving encourages this wasteful process. EV mode has its uses, such as creeping in traffic, but normal driving isn't one of them. For better mileage, stay out of EV.

You mentioned seeing an improvement in mileage by driving in EV. Here is why: The Prius calculates mileage by measuring distance driven by fuel burned; battery SOC is not part of the calculation. Your mileage goes up because you are borrowing energy from the battery. Eventually you have to pay back that energy, and pay it back with interest (the losses in the cycle). Think of it as a cash advance from your credit card. You live pretty well for a month, but then the 21% interest payments start. Your overall mileage will be lower, even though your short term mileage will improve.

Tom

 

I really think toyota should have just put a shhh or quite mode on that button, way to many people think it's something its not.

 

I may be one of the few people who gets better mileage on their daily commute than on the highway. I'm doing about 55mpg on the regular commute of 30-35 miles each way. The congestion helps curb my lead foot.

I've taken 2 trips of 360 miles one-way and I've averaged between 43-48 mpg on those trips. The gas mileage tends to die when you're driving up hills at 70mph...and the coasting down the other side doesn't compensate.

I've also found that there was little difference when I was using the A/C, but now that heating season has arrived (ack), that seems to be affecting the MPG.

 

I live in the Dallas, TX metro and commute a rountrip to work of about 55 miles. At least half of that is on surface streets with traffic lights and stop signs. (I avoid the freeway going to work usually due to its being a parking lot)

I recently took a 3500 mile trip to Salt Lake City and back ... and did a LOT of interstate at 80+ MPH. On that trip I averaged 47.9 MPG. On my work commute and just running around locally, I average about 51 MPG.

My epxerience with what people claim for mileage is that everybody drives differently ... some drive easy and some ... don't. If you were used to something with a lot more power, you may be trying to maintain that "feel" and not even realize that you are doing so.

When you are driving, do you drive by the 2-second rule or are you 20 feet behing the car in front of you (at 50 mph) and tapping your brake pedal every couple of seconds to control your speed?

In a Prius, your best mileage will be in town driving. Check your tire pressure. My 2010 V ... with the 17" Brigestones ... I run 46 front and 44 rear PSI. That is still safely way under the 51 max on the tires.

Are you running regular gas? Running a higher octane than you need will waste money and hurt mileage.

Keep a notebook in your car to record ALL expenses and services. Put it on a spreadsheet and then you can track long term numbers.

Reset your tripmeter after every fill, then you will HAVE TO calculate your real numbers ... the car computer is off about 2 or 3 MPG.

 

These points make a lot of sense. But I am in DC area, where the traffic is the second worst in the U.S. (I heard L.A. is the first). These techniques are very hard to practice here. If you coast and leave a space in front, someone will sure to cut in, you will not get anywhere soon....

 

You are doing very well with 55mpg in commuting. Which part of Maryland do you travel in? I go from Rockville to DC everyday for 50 miles round-trip. I got about 50mpg so far. But it may be too soon to tell because I just picked up the car 5 days ago.

 

I have a 2010 Prius with about 2,800 miles and have been getting about 43-45 miles per gallon. I have heard some discussion about the improvement of mileage after the break-in period. Anyone out there have some information about how many miles per gallon improvement I might expect after another few thousand miles?

 

This one I really don't get = someone please explain... I drive the last 1/2 mile in EV mode. I wake up, start my car, and head out - the ICE kicks in, and at stops slowly charges the battery. After 5 minutes, I'm back near full...

How does this give 10-20% worse mileage (???????????????).

(????) - for good measure...

 

hmmm... interesting thread.

We've got about 4,400 miles on G3 II and do a mix of driving from daily commuting into Santa Fe (high elevation and long hills), to regional travel with various highway driving conditions. Long climbs combined with high interstate highway speeds are the biggest challenge for the Prius mpg, but long downhill coasting sections will offset the climbs proportionally.

I also notice something else no one else has mentioned (that I've read) and that's what pilots call density altitude; higher temperature and higher elevation translate into less dense air, less resistance and potentially better mileage. The opposite is true however, people living in lower elevations with cold conditions will experience denser air that requires more energy to move the vehicle through at a given speed. At our higher elevations we have an indicated lifetime average of 53.5 mpg. My wife and I both drive the Prius, she commutes with it and I use it for regional trips when I have further to drive in a given day so I've been monitoring it closely. I always bring up the average mileage during a tank of gas and find that with non-interstate speed highway driving in Northern New Mexico, I average about 56-57 mpg indicated, but managed a trip to Taos Ski Valley from where I live north of Santa Fe, 180 miles of mountain driving and returned with a trip average of 61 mpg, My average "density altitude" was about 20-25% less dense than average sea level standard atmospheric density.

I keep prefacing my mileage with "indicated" because I have just recently become aware of the know recognized 5% error in indicated mileage. Our last tank was our worst average (all commuting to SF) 430 miles at an indicated 53.6 mpg, yet when filling the car it took 8.5 gallons to shut off, or 50.5 mpg calculated. I haven't been calculating the mileage, until now, just trusting the computer (right), but from now on will cross check both indicated and calculated mileage to either verify or dispute the 5% phenomenon.

Any other high elevation drivers notice higher mileage? I once managed 18.5 mpg with my 100 series Land Cruiser driving across the flat San Luis Valley at 8,000' MSL, I normally get 16.5-17 mpg with it on the highway

 

I wouldn't worry. My consumption was in the 40s for the first tank and has gone steadily up as I've learned how to drive and the engine has gotten broken in.

 

there's a break in period where you get lower mileage than normal. also, that stop and go traffic does not help, especially if you don't accelerate smoothly and coast to a stop.

saying that, my first tank had an average of about 48 mpg (accg to screen), and i'm now doing about upper 50s to 60 mpg on my second tank, but i'm a very careful driver (very good at coasting even when i had my maxima), and one way to work is 30 miles.

 

So I took my Prius to work for the first time today... Drove 27 miles each way on the freeway, some stop and go, and it's telling me I'm getting 29.2 MPG? I got rid of an old truck that got me over 20 MPG... Obviously I'm doing EVERYTHING wrong.... Ughhh

My tank of gas that supposedly was full when I got the car last night looks like it's 1/4 gone already...

I think I have a long learning curve ahead of me....

 

I live in Munich, Germany, and my daily commute is 17km/10,5mi each way. The trip is a mix of stop&go, traffic lights, 30khm/18mph areas/parking lots, 3km/1.8mi highway (done at 110-120km/h/68-74mph otherwise I stop traffic...) and relatively long stretches of 60-80km/h/38-50mph roads. That is not really "city" driving, though all in the city of Munich...
In the morning, especially now that is has gotten cold (about 0-5C/32-41F, the engine warms up for about 5-10 mins and sometimes it kicks in again at traffic lights, not because the battery is drained, but because it has gotten cold during coasting....
I managed only twice to go below 5L/100km/47mpg; the minimum I got was 4,8L/100km/49mpg - the current average over a month is 5.3L/100km/44mpg (as reported by the Prius). Going back, with the car not completely frozen staying outside (rather in the company's car park) and not necessarily on the same road but sometimes over a longer, but less traffic-light ridden roads with higher travelling speeds, I get an average (over a month, that is), of 4,3L/100km/55mpg. I did get on this backward leg a minimum of 3,3/71 and 3,4L/100km/69mpg a couple of times (without ECO! - in normal). The overall commute average is 4,8L/100km/49mpg.
As a comparison, my previous car, a 1.4L diesel Polo, turbocharged with about 75HP, was achieving 5,1L/100km/45mpg and 4.7L/100km/50mpg respectively on each leg, that is 4,9L/100km/48 overall. I never went below 4,2L/100km/56mpg. But this was in late summer when the car gets warm quickly and never started frozen. The values are as reported by the Polo's computer and include the fuel used when not moving.

So the Prius is getting me so far 0.1L/100km/2mpg more fuel efficiency, during a cold fall, with a car that has about 60HP more, it is bigger and more heavy (at least 200kg more). Not bad at all.
In highway driving from Munich to Verona (about 430km/260mi), always in ECO mode, I got an average of 5L/100km/47mpg (and the drive was a mix of 110-120km/h/68-74mph, 140km/h/87mph mainly in Germany and 135km/h/84mph max in Austria). The whole trip is uphill (quite steep at times) from Germany to Italy and then slides down from Brennero to Verona.

Moreover I noticed that the fuel consumption of the Prius in the first 3km is around 8-8,5L/100km/29-27mpg warming up in fall, compared to 9L/100km/26mpg of the Polo in summer...

The EV mode is never to be used IMHO, unless you are driving in a closed area (parking lot) and don't want to pollute/stink around, or when you are looking for a parking spot - I tried to use it during the commute in tight slow moving traffic and and I got one of the worse fuel consumptions ever... Using ECO does not seem to help either, and Power is surely not helpful, rather making things worse. Power is great instead if you want to have fun driving or go fast on a german highway

As I read in the user's manual, ECO is to be used in stop&go situations, and normal mode is to be used at all times. I have to try using ECO in the sections of my commute where I am crawling and doing stop&go and see what happens compared to using it all the time.
But honestly speaking, I am trying to drive the car "normally" and I am getting more and more annoyed in checking the fuel consumption. Though the Prius is not necessarily better, rather similar, than EU low-fuel consumption latest generations diesels outside of town or on highway at moderate speeds (e.g. 80-90mph), in city I think nothing beats it yet. Checking how you drive it continuously can be stressing and takes out the joy of a very silent and very comfortable ride.

Below in my signature the current lifetime average. Mainly "city" and highway.

 

First of all don't panic. I would say there is no way you actually got 29 MPG on your commute unless you had the emergency brake on the whole time. DId you reset the trip meter since you got the car. Sometime the dealer leaves the car on while doing prep and the salesman leaves it on while you sit in it going over the features. The engine will cycle on and off getting 0 MPG. This will be averaed into your trip mileage until you reset it.

As far as the fuel gauge goes a dealer fill up means stopping at the first pump shut off while pouring fuel in at the maximum rate. It was probably just full enough to briefly light up the top pip on the gauge. I get around 100 miles before the first pip goes out so your "fill-up" may have been about 2 gallons short.

Here's what to do to ease your mind on your next commute. If you want to keep the lifetime mileage I would let that stay on the B trip screen. Reset the A trip and then just start driving. After a few minute warm-up with low mileage you will be treated to the mileage rising through the 30s and at least well into the 40s before you get to work.

 

This really have to preface this comment with, "if you live in a relatively flat area." I've seen my battery fully charge while braking down out crazy hills. After using the EV mode a couple times, I've seen the MPG numbers increase on the dash.

You'll figure out where and when to use it. Plus, the kids think it's fun. I don't get it, but they love it.

 

Quote:
Originally Posted by Spartane
If you can, try to change your driving habbits so that you minimize your brake usage.

Here's one technique to maximize your fuel economy:

1. Accelerate relatively quickly with traffic, but allow some space to build up in front of you so that you have something to coast into when traffic slows down.
2. When traffic begins to slow, take your foot completely off the gas pedal so that you are burning no fuel (no gasoline and no battery). The longer you're in this state the better your fuel economy will be.
3. Adjust steps 1 and 2 above to keep your braking to an absolute minimum. The Prius will recapture a lot of energy when you brake, but the process is not as efficient as you'd like it to be.
4. Practice repeating the above three steps to maximize your fuel economy.

I don't drive in the DC area so you may well be right about this. However, my experience up here in Toronto is that those same people who cut in front of me will soon cut in front of someone else, giving me back my space. Also, I try to drive in the right-hand lane as much as possible, so this encourages them to naturally migrate over to the left.

I drive about 33 miles each direction (mostly highway) to/from work, and it generally takes me about an hour and 15 minutes each way. I'd guess I might be able to shave that by maybe 5 - 10 minutes by driving more agressively and moving to the faster lanes, but for me the Prius is so smooth and enjoyable to drive in stop-and-go traffic, that it's better to just sit back and either enjoy the satellite radio, or listen to an audio book. My best tank, measured at the pump, was 65mpg (US). I have yet to go below 60mpg, although it looks like that will change to something like 57mpg on my next fill-up with the colder weather now beginning (and likely much worse during the colder Jan/Feb months).

 

I also live in the DC area (Rockville) but I take the Metro to work in DC and don't often take the car into town. However, the traffic in the suburbs is also pretty bad. In Rockville it is hilly and there are numerous traffic lights. Also, my car seems to be equipped with red-light triggering mechanism because almost every light I come to turns red. I can't just slow down and coast towards the traffic waiting at a light until it turns green; I almost always have to apply the brakes and come to a full stop, wait, and then start up again, usually on an uphill incline! When climbing a hill, especially from a stop, the mpg indicator goes way down. There's no way I can keep it in the mid range unless I keep the speed well under, say, 15mph, which I can't do with people behind me.

 

I figured out a long time ago that someone cutting in front of you has a much bigger effect on your attitude that any effect on your travel time. Assuming everyone leaves a proper 2 second interval between themselves and the car in front 30 people would have to cut in front of you to make your trip one minute longer. In actuality it has even less effect because the ones cutting in usually tailgate the car in front of them costing you about a second.