# questions for prius owners



## azndriver87 (Mar 23, 2015)

I am getting 32mpg average for city driving (after a 20 miles test in city, that's a lot of driving for city). Is this normal?


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## LEAFdriver (Dec 28, 2014)

azndriver87 said:


> I am getting 32mpg average for city driving (after a 20 miles test in city, that's a lot of driving for city). Is this normal?


What year is it? How long have you owned it? I've never gotten less than 45 mpg in mine. So the answer is NO....that is not normal!


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## azndriver87 (Mar 23, 2015)

I just bought it, 2007, 97000 miles.

I think it's still under warranty. Hybrid components have 8 years/100,000 miles warranty.


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## gprimr1 (Mar 7, 2015)

Yes, the hybrid system is 8 years, 100k miles. 

One thing I've noticed is not gunning it from stop lights hurts.


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## Beur (Apr 14, 2015)

Wow that's awfully low, you might want to adjust your driving to increase your gas mileage.


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## Fauxknight (Aug 12, 2014)

City, total drive time, temps, other weather conditions? A lot of factors play into the Prius MPG numbers, but yeah 32 is very low.

You get somewhat low gas mileage right when you turn the car on, as the ICE needs to run until it warms up. Low temps will require longer and more frequent warm ups. Conversly warm temps mean short warm up times and almost non existent follow ups.

Idling for long periods of time, particularly with the AC on will use battery power, which will force the ICE back on when it gets low enough.

Rain, snow, or other inclement weather increases roll resistance which will require more power to get you moving and to keep you moving.

Driving around on electric will use the battery power up forcing the ICE to run more to charge it. The ICE is less efficient at charging the battery than it is at moving the car, so it's desireable to run on the ICE most of the time.

Accelerating hard will use more fuel, when accelerating try and keep the HSI power bar at just slightly over half, this keeps the engine in its optimum power range and keeps the ICE running instead of swapping to EV mode.

Braking hard will kick the friction brakes on, wasting power. To optimize the regenerative braking, brake slowly or not at all, keep the regen bar on the HSI at 75%-80% or less of its maximum...I know it says regen but 75-80% is the max on regenerative braking, beyond that it kicks in the friction brakes.

Learn to pulse and glide. Accelerate at the optimum point listed above (just over half of the HSI) and when up to speed pull back on the gas pedal until no power and no regen is showing, now you are coasting (theoretically with the ICE off) thanks to the low air resistance and low rolling resistance of a Prius. Optimum areas to do this in are 25-35mph zones.

Regardless of power demand the ICE must run if the vehicle is traveling at 45mph, this is due to the transmission set up and the red line RPMs of the electric motors. Do not put the car in neutral and coast down a hill to over 45mph, you can over rev the electric motor in an older Prius.

Drive smart, anticipate lights and other traffic conditions...I.e. Don't gun it just to get to a red light, take it easy, let the light change on its own, then slowly accelerate back up to speed when it's appropriate.

Yes, there's a reason people hate Prius drivers, driving like a jack ass nets you the best MPG. The trick is to find a balance where you are getting good gas mileage, but not pissing everyone else on the road off.


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## Beur (Apr 14, 2015)

And, to help better our reputation stay out of the number 1 lane unless you absolutely positively have to be there. I've seen too many Prius owners cruising in the number one lane backing up traffic.


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## Fauxknight (Aug 12, 2014)

Also, drive in D and not B. B is about worthless unless you live at the peak of Mt Everest.


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## Beur (Apr 14, 2015)

Only time I drive in B is when coming down the mountain on steep hill.


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## Fauxknight (Aug 12, 2014)

My friend had an issue where his Prius lost mileage once. Over the winter through some deep snow one of his brakes got jammed shut. He noticed a loss of MPGs, but was still getting in the 40s, by the time the problem was found in the spring he needed a new pad and rotor (at his cost, not a warranty item).


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## Beur (Apr 14, 2015)

Anything consistently below 45 MPG would concern me.


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## Fauxknight (Aug 12, 2014)

Beur said:


> Only time I drive in B is when coming down the mountain on steep hill.


Yup, I guess I should explain B since I went over everything else:

B is engine braking mode, it's designed to slow the car down during long braking procedures (like going down a mountain) without overheating the brakes. To do this it throws away a lot of excess energy instead of using it for regenerative braking. Your regen meter will show very high, but near half of what it is showing is not actual regen (just like anything past 75-80% isn't actual regen under normal conditions). B mode will always net you lower MPGs and should only be used in extra-long several-mile constant-braking descents.

A Prius can take a solid amount of downhill braking without needing to be shifted into B. In fact a Prius will never charge the last 20-25% of its battery from the ICE, it leaves that open only for regenerative braking, and, unless you live on a a mountain, you will almost never see the battery at 100%.


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## Beur (Apr 14, 2015)

I've only seen my battery at 100% when coming home back over the mountain. The last 50% of the trip is downhill.


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## Older Chauffeur (Oct 16, 2014)

For comparison, have you typically gotten EPA estimates for city driving with other vehicles? I agree with other posters that driving habits affect your mileage, along with weather. I owned an '04 and an '06 prior to my current '12 Plug In, and never saw mileage below 48, and that was only one time on a fast interstate highway trip. What are you averaging overall, with combined driving? If you are averaging 50 or thereabouts per tank, you are probably okay.
Re the warranty, check the original delivery date (on service orders or ask a dealer). Your eight years may have already ended. The exception would be if you are in a CARB state, where it is ten years/150k miles. But if your battery charges and will power the car for brief periods on flat ground, the battery warranty issue may be moot.


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## Beur (Apr 14, 2015)

I've been doing better than EPA estimates on the new 15 Prius, though I've only had it a month.


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## Older Chauffeur (Oct 16, 2014)

Beur said:


> I've been doing better than EPA estimates on the new 15 Prius, though I've only had it a month.


Yeah, I did better than the estimates on my first two, 54 mpg over a total of 130 k miles. Conservative driving is the key, especially on the freeway. My Plug In is a different story altogether, with the larger Lithium battery allowing the ICE to run less, especially at lower speeds.


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## madman2k (Apr 22, 2015)

I would recommend checking the air and fuel filters, using non-ethenol gas for a tank and running some GUMOUT or Seafoam through it to clean the injectors a bit. Also, check all the tires - if you've got tires like mine, the sidewall calls for 51PSI and the car calls for 35 which would be under inflated, and the dealership might have gone with the door placard PSI. I run close to sidewall PSI with Goodyear Eagle LS-2's (cheap, noisy but pretty good for MPG). The ride gets bumpier and it brings out rattles in the car, but I'm thinking you didn't buy it for its luxuriousness.

When Ubering around town I get from 56 to 59MPG as a daily average over a couple hundred miles or so. Having the engine fully warmed up really helps, as does anticipating red/green lights and accelerating just fast enough. Don't floor it to a red light, but some extra throttle input to make it through a stale green light is better than stopping prematurely and having to start from 0.
It is possible to get worse MPG by accelerating too slowly, but it's really slowly so that's probably not the problem. Think loaded semi acceleration pace if you want to maximize it.

When I commute to my day job, 9 miles each way, there are times I will really use the heat or A/C for the day and be late for work so accelerate faster from each stop sign and end up with about 42MPG for the day.

Pushing a headwind at 80MPH on the freeway with a lot of weight in the car it might break just under 40, but 32 definitely means something's wrong.

The Gen 2 (what you have) is not quite as good for MPG as the Gen 3 (2010 and up) in certain conditions, namely when the A/C is on because the newer ones have a different A/C setup, but that's a good percentage below the EPA rating.


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## Fauxknight (Aug 12, 2014)

The sidewall is max PSI, not necessarily recommended. I suggest somewhere inbetween the recommended and max, upper 30s to low 40s for most tires.


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## UberXTampa (Nov 20, 2014)

Under extremely unique conditions this might be


Fauxknight said:


> Yup, I guess I should explain B since I went over everything else:
> 
> B is engine braking mode, it's designed to slow the car down during long braking procedures (like going down a mountain) without overheating the brakes. To do this it throws away a lot of excess energy instead of using it for regenerative braking. Your regen meter will show very high, but near half of what it is showing is not actual regen (just like anything past 75-80% isn't actual regen under normal conditions). B mode will always net you lower MPGs and should only be used in extra-long several-mile constant-braking descents.
> 
> A Prius can take a solid amount of downhill braking without needing to be shifted into B. In fact a Prius will never charge the last 20-25% of its battery from the ICE, it leaves that open only for regenerative braking, and, unless you live on a a mountain, you will almost never see the battery at 100%.


speaking of brakes, today I took advantage of Monday being a slow day and serviced the car. Toyota service said my brakes were perfect! At 168k miles I never changed brake pads so far. Just regenerative breaking and adjusting my speed! Very rarely I need to brake hard.


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## madman2k (Apr 22, 2015)

Ah. There were some folks on http://www.cleanmpg.com that swear by max sidewall PSI, said it has extended the life of their tires a bit so I figured as long as I don't exceed it they should be fine. Some go over it, but I don't want the ride to be crazy bumpy on these rough roads here.


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## Fauxknight (Aug 12, 2014)

High PSI doesn't necessarily extend tire life as much as avoiding low PSI. As long as it's within the limit it shouldn't get any unusual wear. Definitely a bumpier ride as you crank it up though, can't recommend going too high when using it a livery vehicle.


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## azndriver87 (Mar 23, 2015)

tire PSI, unless it's completely flat on the ground, should not affect the mileage that much.

I "reset" the counter on the energy/consumption chart like 15 minutes after I started driving.


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## Older Chauffeur (Oct 16, 2014)

I forgot to mention tire pressure in my post. The members at PriusChat.com seem to mostly recommend 42/40 f/r to get the best mpg without sacrificing too much in the ride department. Tires last better at these settings. Check them cold at least once a month. Tire pressure will indeed affect fuel economy on any car.


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## Older Chauffeur (Oct 16, 2014)

azndriver87 said:


> I am getting 32mpg average for city driving (after a 20 miles test in city, that's a lot of driving for city). Is this normal?


Your experiment got me wondering, so I ran a similar test. (I usually track per tank mpg, rather than just a few miles.)
I drove 24.9 miles, on a closed loop, no freeways, with three stops. I drove in Hybrid mode rather than EV, trying to get as close as I could to your test. I averaged 57 mpg at an average 24 mph. Keep in mind that mine is a plugin, so the battery has a larger capacity, giving more boost than in the standard hatchback. I goosed it just enough to keep the ICE going most of the time, finishing with the battery SOC close to what it was when I started. (9.8 vs 11.6)
I haven't seen any updates- have you experimented further or checked with a dealer about your car?


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## azndriver87 (Mar 23, 2015)

actually so yesterday I drove in DC for 70 miles, i was able to get 47 mpg driving convervatively.

However I noticed couple things:

1) in the morning, my hybrid batteries are completely drained
2) when I park in a parking lot with the engine running, the battery will drain after 20 minutes from full charge.

are these normal?


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## Older Chauffeur (Oct 16, 2014)

Sounds like your experience yesterday was normal, but I would still suggest checking your tire pressure and increasing it to the 40psi area. Toyota recommends two psi higher in the front over the rear for handling.
With regard to the SOC on your car, it has been over three years since I sold my '06, so I'm having trouble remembering just how it acted. Try visiting PriusChat.com and reading/asking there. It is a great site for Prius owners.
FYI, the auxiliary battery will drain quickly sitting parked listening to the radio with the ignition in the accessory position. Better to have the car in ready mode so that the ICE will run as needed, as you were doing.


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## Huberis (Mar 15, 2015)

Fauxknight said:


> City, total drive time, temps, other weather conditions? A lot of factors play into the Prius MPG numbers, but yeah 32 is very low.
> 
> You get somewhat low gas mileage right when you turn the car on, as the ICE needs to run until it warms up. Low temps will require longer and more frequent warm ups. Conversly warm temps mean short warm up times and almost non existent follow ups.
> 
> ...


Where does a Prius find its best fuel economy? My assumption was where it is warm and where the driving is mixed, that is to say a bit of stop and go.


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## Fauxknight (Aug 12, 2014)

Huberis said:


> Where does a Prius find its best fuel economy? My assumption was where it is warm and where the driving is mixed, that is to say a bit of stop and go.


The hotter the better up until you have to use the AC.

Stop and go traffic is technically worse than a steady forward pace, but the regenerative braking helps mitigate that by recovering some of your excess forward momentum/energy.

Best traffic conditions is a flat empty road where you can pulse and glide, pulse up to around 38 then glide down to under twenty...again, you want an empty road to P&G over that wide of a speed range. Can get 80 plus mpg doing this. Hills are actually not too bad under P&G as long as you are pulsing going up and gliding going down

Straight line steady speed seems to be best around 45ish, can get mid-upper 60s in mpg under optimal road/temp conditions don't this.


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## Huberis (Mar 15, 2015)

Thanks. I thought the regenerative braking benefit was more pronounced.


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## Older Chauffeur (Oct 16, 2014)

The plug in gets more out of regen, making it possible to exceed the estimated range indicated by the computer. Or maybe a better way to say it is that the larger battery stores more energy from regen.


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## Fauxknight (Aug 12, 2014)

It's simply the matter that you have to spend *X* amount of energy to get the car moving and regenerative braking only recovers a % of that back, so you lose energy every time you brake. Now a normal car that brakes to a stop loses 100% of the energy invested into it by its engine, but let's say a hybrid recovers 50% of that energy. Under this assumption the hybrid loses half as much energy at every stop as a non-hybrid does.

Multiply that by the fact that a hybrid will cut the engine and use near 0 energy while stopped (actually the engine cuts well before you stop) VS a non-hybrid that will continue to idle using many times as much energy while stopped.

Also take into account that in order to maintain forward momentum you have to overcome energy lost due to friction and wind resistance, hence the aerodynamic profile and low roll resistance tires that are standard on most hybrids. So not only does a hybrid recover energy while braking, but they tend to lose/waste less of the energy already invested into them even when simply moving forward.

So the reason pulse and glide (P&G) is so effective is that when the engine is in its optimal RPM range it's producing the most efficient amount horsepower/torque for the amount of fuel beng consumed. So you accelerate staying within that most optimal range and then pull back and let it coast as far as it can with its low wind/roll resistance. You've also got resistance from the engine, but on a Prius with the pedal in the right position the resistance from the engine is almost as low as being in neutral, combined with the fact that the engine/ICE will turn off while gliding.

This hypermiling technique is not unique to hybrids, but the full blown version of this in a normal car is dangerous, not that people don't do it anyways. You accelerate up to speed, go to neutral, and then turn the engine off while you coast. This is sometimes referred to as EOC, or Engine Off Coasting. So...what is super dangerous in a normal car, is just regular everyday driving in a Prius.

Driving straight line at 45ish is also extremely good in a Prius because, even though you keep the ICE on full time, that's approximately the speed you are going to be travelng at if you hold the power level at that perfect/optimal RPM range.


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## Fauxknight (Aug 12, 2014)

azndriver87 said:


> actually so yesterday I drove in DC for 70 miles, i was able to get 47 mpg driving convervatively.
> 
> However I noticed couple things:
> 
> ...


1) No
2) Maybe

1. The battery should remain at the SoC that you leave it at, or very very near that level. A lot of times people unintentionally drain their SoC when they near their house, just because the car tends to automatically use EV mode in the slower neighborhoods. Actual overnight discharge can indicate either an electrical issue or a fairly worn battery.

2. Depends on what you are running, with no lights, no AC, no fan or any other extraneous electronics and a battery at top charge should last longer than than. Conversely running everything at full blast and it'll bottom out in less than 20 minutes. Older batteries of course can't hold as much of a charge, but even the 10 y/o several hundred thousand mile batteries tend to still be around the 80% mark.


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## Just one more trip (Jun 14, 2015)

You want a nicer running older Prius with better MPG? Try running premium gas. After a couple of tanks, your car will thank you.


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## Nagodesi (Aug 20, 2015)

what every Prius owner should know is the battery gets hot after use, the hotter the battery the worse perfomance, run the ac in the car for comfort and cooling off the battery, i get an average of 56 mpg , i have a 2015 with 9500 miles.


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## Fauxknight (Aug 12, 2014)

On a Prius the intake for battery cooling is indeed inside the vehicle, it's on the driver's side of the rear seat near the bottom. Make sure this is never blocked, objects/trash on the floor on that side can easily accidentaly block the intake and you will get a noticeable loss of MPGs.

You'll still get better numbers with no AC, but yes you do get a small extra return there when running the AC. There probably is a break point where it's just better to run the AC, but I hope on those freakishly hot days you're running the AC already for you own sake.


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## Nagodesi (Aug 20, 2015)

i'm getting a very good in the 60's with a/c on


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## UberRach (Mar 10, 2015)

I drove my Prius through some mud off-road at a festival and for the next month after that I was getting low 40s when I used to avg about 52 mpg. Took my car through the car wash and after that I was back to normal. So I'm guessing mud was blocking something. Yep, I'm a genius.


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## Nagodesi (Aug 20, 2015)

added weight


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