New owner confused as hell

A little information would help; otherwise it could be anything:

1) What is your typical drive?

2) What is the weather like?

3) What type of tires and tire pressure?

4) How old is your 12V battery?

That should get us started.

Tom

 

This is a regular question from new owners and the answers could be many. There should be a form to fill in somewhere on this forum that asks you many questions about the use of the car, the tire pressures, length of journeys etc etc.

First thing I'd say is check your tire pressures as having the pressures too low (even by 1 or 2 psi) can make a BIG difference to your economy. Some of the members on here inflate their tires over the recommended pressures to get even more mpg's out of their car, but just having them at the correct psi will make a big difference compared to them being too low.

I'd give that a go first and see if it helps. Otherwise the lower mpg's could be due to the cold weather - anything lower than 5c/41f can adversely affect mpg's, esp on short runs of 5 miles or so.

The above will get you started before discussing whether you have a failing 12v battery (they last about 4-5 years) or other issues. Let us all know how you get on.

 

It's super cold now. Even I'm getting 43-47mpg.

 

Don't panic.

You just drove it off the lot. 290 miles? Too early to determine anything. I'd just relax about your MPG this tank...next time you fill up...reset, try again.

Hunt around this forum, there are plenty of threads about advice as far as improving your gas mileage. You can apply whatever you wish, to whatever degree you wish. But there are too many unknown variables at the moment, and personally, I'd just throw the MPG's on that first drive off the lot tank...out the window and not panic.

If it's not just the enviroment...cold...or tire pressure...or adapting driving style..or you DO have a problem...that will become evident...but at this point? Maybe I check my tire pressure, do the usual look and listen I would do with any new vehicle I've purchased..but mostly I'd just relax...

I think you should expect better than 37.2....but since this is your first tank? (Did you fill it or was it the dealership?) I wouldn't worry. Get at least 1 full tank beyond this one...

 

I'm thinking short journeys and low tire pressures.

There was another thread on here where the guy was getting poor mpg's after just buying the car and it turned out his psi's were 25! He's popped them back upto what they should be for the car and got a significant increase in economy.

 

Hmmm, handling you can improve. Slam your ride, add a strut bar, and upsize your wheels. Power you can't do anything about, easily.

As for your mileage, I would keep resetting that sucker until you're well-practiced getting a higher average. There's no shame in that. Youre in the early stages of ownership. It's hard in this cold weather but doable with a little more experience.

 

Is the 17 miles roundtrip mostly city or highway? Is there lots of stop and go? How long does it take, in each direction?

Please answer the questions at http://priuschat.com/forums/gen-ii-...-answer-these-questions-esp-if-youre-new.html or at least answer the rest of qbee42's.

We don't know what you've changed your driving style to. Doing certain things like accelerating so slowly that you're trying to stay in EV will not help your mileage.

 

I'm not near the expert that others are.......but I would say your well on your way to enjoying the benefits of owning a Prius...............Yup.....looks like you could use a new 12 volt battery.

Happy motoring !!!!!

 

The best thing I can say is, once the car's warmed up, try to get the yellow bar to shoot (and stay) at 100mpg as much as possible. That means lift your foot off the gas when you can, give yourself plenty of time to coast and brake.

In school, have you ever tried to calculate your final grade before the course is even finished? For example, if you got a 65% on one test but 90% on the next, you'd have a C+ average. Well you can do the same thing with your mileage by keeping a close eye on your mileage bar. If you got 12mpg accelerating to a certain speed, try to make up for it by coasting at 100mpg for the same distance. That way you can get a good idea of what your mileage is before it's set in stone on your 5-minute interval bar. Just think of it as a game and have fun.

 

Hi Mattleerocks,

The most bang for the buck handling wise is the BT Tech, or other brand chasis stiffening plate. This stiffens up the rear end of the car, and makes things much more predictable. Do a search and find the copious threads on these devices.

Bigger tires will zap your fuel economy. 17 inchers might put a 20 percent decrease on the mielage. Try out the stiffening plate, and maybe a Tanabe strut bar first, and see if you can live with the car after those. The chasis stiffening plate is widely regarded as nearly miraculous in its effect on the 2004 to 2009 Prius handling.

Based on your comments, I am thinking your also a lead foot while braking. This basically throws away allot of the hybrid advantage. If you brake heavy, the friction brakes are used, as the braking power exceeds the braking power capacity of the electric braking, and the car automatically switches to friction brakes. So, hang back from the traffic ahead, and brake for a longer distance - about 200 -300 yards from 40 to zero.

Your one-way trip is about 8.5 miles, which will be challenging to get great mileage. Your really need to tell us were you are for us to help you. As that will tell us what the weather was in the recent past. You do not need to be specific, just narrow it down to one corner of a state or so.

Heavy acceleration dips into the battery , which then has to be recharged. This transfer of energy results in more losses, and worse fuel economy. Now, you do not want to accellerate like a granny either - as that will be similarly poor in mileage - yea, you can get 30 mpg crawling out of stop lights, as well as flooring the throttle. Its been documented many times!

The best accelleration rate for mileage is close to average traffic, or just a hint slower, usually.

The other thing that newbees need help with is the way the accellerator pedal works. In the Prius the pedal is much closer to the theoretical accleration pedal, and less like a speed pedal as in traditional cars. In traditional cars you have to hold the pedal at a much deeper level the faster you go, as its actually attached to a throttle plate, and your holding the plate open. In the Prius the pedal is attached to a computer. So, pressing it accelerates the car, but once up to speed pull back on it, and you will see the car continues to travel along at that speed, but with better and better mileage. At some point, in pulling back, the car will finally start to slow down. You want to get used to finding the point where the car just moves along at your desired speed , but does not slow down. Over the months, how far to pull back on the gas pedal after acceleration will become second nature. You might want to stretch the calf muscle to have enough flexibility to feel comfortable, how far you have to pull back on the throttle pedal.

If you manipulate the pedal optimully, the computers will keep the throttle wide open, and load the engine with the effecitive gearing ratio of the transmission , and you get a result of very low pumping losses and the engine will be operated near the peak of the BSFC curve, and you will get great mieleage.

Those are the start. It will take this and more reading, and learning to get up into the low 50's MPG, which will be about the limit for your short commutes. Its not that hard, just different. And its not that much different in your average travel speed either, as that is usually limited by light timing and the number of other stops one has to make in a trip, I find.

If your commute was longer, and in a 70 to 85 F weather, and you allowed yourself to use a full range of hypermiler techniques, 70 mpg would be a good goal to shoot for.

 

Or use this time to coast/glide. The sooner you can start your glide the less fuel you use.

This is excellent advice and not usually given out. I found this out myself after years of driving the Prius. In essence, get up to your desired speed, lift off the throttle slightly and reapply throttle to maintain your desired speed. It sounds simple but most people just keep their foot on the pedal, after reaching their desired speed, and this can cause you to still accelerate but at such a slow rate that it takes a long time for you to reach that next digit in MPH. During this time you are wasting fuel. Multiply this by the number of times you accelerate during an entire tank and you can see why this can really increase your efficiency.

 

Hey there, I just got my first Prius a month ago (my first car, too!), and I've been experimenting like you to figure it out. At first my mileage seemed to be high 40s, and I knew there had to be a way...

Biggest suggestions from what I've seen so far:

1. Stay far behind other cars so when they brake for no reason you can keep moving. Momentum, momentum, momentum.

2. Don't accelerate slowly when the car first turns on thinking that will help. Just get to the speed you need to normally and then...

3. Ease up on the gas pedal once you're rolling. What will feel like not much up with your foot can change the mpg from 20s to 40s or 30s to 50s while pretty much maintaining speed.

4. Short trips are the worst. Combine errands, if you need to stop, wait till the way home when the car is warmed up. If I know I'll be inside for 5 minutes only at the bank or drugstore (maybe not everyone likes this, it's at your own risk, but...), I turn off all heat, lights, the screen display, etc., so that the gas engine turns off, but leave the car on. I then manually lock the door with the key you can pull out of your fob. The car sounds and largely looks like it's off, and it won't go through the annoying startup process again when you leave. I maybe should also add I tend to be in pretty small towns, relatively safe when I do this, since if someone got in it's the only way the Prius can really be stolen.

5. Get those babies to 42/40psi or 40/38, just something a little higher than what you probably got them at, which is likely mid to low 30s. I did this last week and mileage popped over 10% I'd say.

6. Now for the most important...learn to GLIDE (which is different from regular coasting in another car). To get good with it, after the first five minutes of driving, when you're going at or under 40mph on a slight downhill, take your foot off the gas for a second. If you have the "Energy" screen up, you'll see blue arrows appear, heading to the battery. It will say 99.9mpg for this regenerative braking, BUT the most efficient will be when you ever so slightly put your foot back on the pedal so that ALL arrows of any type disappear from the screen. If you see yellow arrows to the wheels you went to far down on the pedal, the electric engine will now be running, so let up again to see no arrows at all. This is a glide, and this is the most efficient state the Prius can be in. First learn to do it on a downhill, then learn to incorporate it in your everyday driving as much as possible in a safe way. Pictures found in thread below.

(OK I tried to put a link, not allowed cause I just registered finally to respond to you. Google "pulse and glide pictures" and click on the Priuschat link that comes up)

I got 68.6mpg on a 20 mile trip the other day after a month of working at all this, so you can definitely do it. Update and let us know how it goes after more experimentation!

 

Thanks for answering the questionnaire. So, can you double check on the make and model of tires on your Prius please? They might've been changed.

Concur w/the advice about not braking too hard and thus throwing away energy (by engaging the friction brakes). I used to brake (what I thought was) pretty lightly but once I got a Scangauge and was watching BTA (battery amps), I found I was actually braking a bit too hard and potentially losing a bit more than I'd like to resistance.

As for HVAC settings, really? You don't have the heater on at all? You have the either the fan to off (with any temp setting) or fan on with temp at LO, despite 40 degree temps in the morning?

Yep, your 12 volt needs to be changed.

If your trips are 8.2 miles and in the city, that's definitely not optimal for mileage. That's a fairly short trip and I wouldn't expect a huge amount more mileage (say 50+ mpg) in the city w/o serious hypermiling w/current weather conditions. It'll improve once the weather warms up.

In your current cold weather, blocking the grille would help.

ConsumerReports.org - Most fuel-efficient cars might help you set expectations. If some of your expectations are based on EPA #s, see http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html.

 

I'd say get this 12v replaced asap. A duff 12v will sap power from the HV battery which will be almost continuously trying to charge it up. This then results in the HV providing less assistance for mpg's etc.

You might also get weird electric issues with a failing 12v - odd error messages, dash lights coming on and off, as well as other weird stuff too numerous to mention. It's worth the peace of mind to spend $200 on a new 12v.

 

One of the ways a 12 volt battery can fail (not the only way) is for one cell to die. Then it never approaches 12 volts, and the charging system tries continuously to get it to 12 volts, draining energy you were hoping to use for MPG.

The Prius has an odd battery, with thinner terminal posts than common in America. The Toyota dealer sells the only battery that fits without modification for about $140 (and labor if you let them install it)

elearnaid sells a Optima Yellowtop battery and a kit to modify it to fit in the Prius for $165 including shipping, if you are even mildly a DIYer.

Toyota Prius 12 Volt Auxiliary Battery with install kit for 2004 - 10

There are illustrated 'how to' threads here showing the simple steps. (there is some parts that are harder to remove, folks offer tips on how they succeeded)

Here is an excellent one by hobbit
Prius 12V swap

Every car's MPG is effected by weather, (and the driver's reaction to weather) on a Prius there are graphs to make this obvious. Depending on where you live, your MPG will raise and fall in a yearly cycle. (here is one for Minnesota)

http://john1701a.com/prius/documents/Prius-2001_MPG_Graphs_Lifetime.pdf

Here in Mississippi, my graph would dip down to 40 in winter, up to 47 in spring and fall, and dip to 42 in summer. Largely because I run the heater and A/C, but also because the engine takes longer to heat up in winter.

Accelerate like there is no tomorrow, deaccelerate like you have no brakes.

 

Yep, 12V battery and gliding. I don't get extremely great mileage because I don't glide as effectively as I could.

But last night I was making a short out and back drive with an hour cooling time in between 3.1 mile legs. I was determined to do as best I could with the crappy situation. By using the terrain as much as possible and doing some extreme gliding, I kept it at 46MPG for both legs of the trip. It was about 40f outside.
But I was alone in the car and alone on the road, nobody to annoy by gliding down to 30mph in a 55, barely cresting a hill at 20mph and then gliding down the back side, etc.

In another car years ago I would have bombed that drive at up to 70mph - and shortened it by maybe 30 seconds? Not much to gain time wise on a short drive but it can sure kill your FE.

- D