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Discussion Starter · #1 ·
I took a 427 mile trip from central Massachusetts to Sunday River Ski Area in Newry Maine and back today. The dashboard display showed 37.7 MPG for this trip. I had reset the MPG after warming up the Rav4 and getting on the highway.

Fuelly, which I use religiously to track mileage, says I obtained 36.7 "real" MPG after filling to the brim with 3 cycles of the pump shutting off. This is the way I filled it yesterday before heading to maine so it's probably accurate within a few ounces of fuel usage. My 2-tank average (the dealer gave me a full tank last Thursday) is 32.8 MPG which I suspect will rise over multiple tanks and as warm weather approaches.

On today's trip I did only a little 'hypermiling', staying at or a couple of MPH above the posted limit and following big trucks occasionally on the freeway. The weather was warm today so I turned off the climate control after lunch. I was on 65 or 70 MPH freeways about 60% of the trip and the rest was secondary roads of 30 to 60 MPH.

My signature below will show the average MPG over time. Please feel free to add your MPG readings so we can all benefit from them
 

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I wish that Toyota would produce a diesel RAV for this part of the world - my sister gets 48 mpg with her diesel VW Golf driving at 75 mph (But of course we don't know what her mileage will be after/if VW fixes its bugged emissions software situation!).
 

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Discussion Starter · #4 · (Edited)
I would expect that in hot weather the cool gasoline from the underground tank would expand in the heat above-ground and possibly damage the tank or filler neck. It's winter here in New England so that's not a problem for me. I also am cognizant of the expansion potential when filling and only do the 3-click topoff when I expect to drive at least 20+ miles immediately afterward to give the tank room for expansion.
 

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I gassed up today for the second time since buying my car on Jan 5. Here are my numbers.

Tank 1 - car computer read 33.0 mpg - 385 on odometer. Full tank - 12.503 gals - my math showed 30.79 mpg.

Tank 2 - car computer read 34.8 mpg - 791 on odometer. Full tank - 11.563 gals - my math showed 35.11 mpg.

I was surprised it stopped at 11.5 gallons today so I went another cycle to be sure it was full. I am happy with the MPG I have been getting with my Hybrid Rav4 so far, I look forward to better numbers this summer. I think I am going to join fuelly today.
 

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My wife had her second fill up today. I'm surprised her mileage had improved significantly, perhaps there is more city driving in the second period picking our little one at the daycare.

There's a total of 1,243 km distance traveled on the odometer and 84 L of gasoline consumed during those two fill ups --> 33.6 MPG.


She was surprised I was interested in her gas station bill and how many kilometers she had driven, lol. Women seem to not care too much about fuel efficiency but to play safe, I asked her to keep the car in ECO mode. She can just step harder on the gas pedal if she wants more oomph. :)

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Edit:
My bad, I overestimated MPG as I forgot to subtract the kilometers she had driven prior to the second fill up. Will determine her MPG once she goes for her third fill up.

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Edit 2:

3 fill ups. 1,597 km / 123 L = 12.98 km/L = 30.53 MPG
 

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Discussion Starter · #7 ·
Just noticed the Rav4 Hybrid's 2.5L Atkinson cycle engine has a conventional, belt driven, water pump. My last Prius (2012 Prius V) had the 1.8L engine and it had an electric water pump. I wonder if this will lead to increased fuel use during the colder weather as the engine must operate to provide cabin heat...
 

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I've filled up twice. By manual calculation, I'm averaging 32.44mpg. But my first tank was probably sub-par due to unusual driving conditions. I joined fuelly, but it isn't counting the first fill-up since it doesn't know where the starting point was.

On the point of filling up, I wonder about the "low fuel" warning. It seems to turn on after about 11 gallons consumed, meaning there's still 3.8 gallons in the tank. There would be around 3 gallons remaining if I ran it down to where it claims there are zero miles remaining. Has anybody tried running it down to 1 gallon remaining? I would like to be able to drive longer between fill-ups, i.e. fill up with 13-14 gallons instead of 11 gallons.
 

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I've filled up twice. By manual calculation, I'm averaging 32.44mpg. But my first tank was probably sub-par due to unusual driving conditions. I joined fuelly, but it isn't counting the first fill-up since it doesn't know where the starting point was.

On the point of filling up, I wonder about the "low fuel" warning. It seems to turn on after about 11 gallons consumed, meaning there's still 3.8 gallons in the tank. There would be around 3 gallons remaining if I ran it down to where it claims there are zero miles remaining. Has anybody tried running it down to 1 gallon remaining? I would like to be able to drive longer between fill-ups, i.e. fill up with 13-14 gallons instead of 11 gallons.
You'll find that the cruising range isn't too accurate. Its based on the current average MPG and an estimate of remaining fuel. You might even see it go backwards or just stop moving. The actual gas gauge is the most reliable measure of your remaining fuel. Be aware that the system will not let you run it dry, it will shut down the ICE and force EV mode till the battery is low. So learn the gas gauge and believe it.
 

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You'll find that the cruising range isn't too accurate. Its based on the current average MPG and an estimate of remaining fuel. You might even see it go backwards or just stop moving. The actual gas gauge is the most reliable measure of your remaining fuel. Be aware that the system will not let you run it dry, it will shut down the ICE and force EV mode till the battery is low. So learn the gas gauge and believe it.
I'm not sure I fully understand. But here's a question that might help me understand. What if I drove around the gas station in circles until the car was forced to run on battery only, and then I filled up the tank. How many gallons would I be putting in?

Part 2: Would that void the warranty on the battery? :D
 

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All you need to understand is that the cruising range readout is not reliable, it'll read zero when you still have a couple gallons left. The fuel gauge is reliable.
 

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Discussion Starter · #12 ·
The way fuel usage and thus miles remaining is calculated relies on a marginally accurate system. The pulse width of the fuel injectors is known by the engine control computer. The fuel rail pressure is also known. Since these can vary with temperature and other conditions it's not possible to entirely accurately measure the fuel used. Rather, it's an estimate of fuel used based on millions of very small samples of injector pulse width and measured (or assumed) fuel pressure, density and viscosity.

From my experience with several Toyota hybrids over the years it appears that range remaining is artificially reduced due to an assumed few percent inaccuracy in fuel usage estimates by the system. Conversely, the displayed MPG seems a few percent higher than when calculated at the fuel pump. MPG displayed is not really regulated so can be inflated a bit as a marketing tool with no repercussions. Fuel remaining (and thus range to empty) can be underestimated and provide a safety margin without any negative repercussions since it will never leave you stranded with no gas in the tank.

Take all these trip computer values with a huge grain of salt. They're OK to use for comparison tank-to-tank but I wouldn't assume they're anything but rough estimates. Knowing how much fuel remains in the tank when the range value shows 0 miles will give you that peace-of-mind that you won't accidentally run out of gas. Relying on these values is not going to get you stranded; but it's not going to maximize your range between fill ups either.

Unlike the Prius, the Rav4 hybrid does not, apparently, use a fuel-cell type gas tank. On the Prius family, the "gas gauge" is more of a "guess gauge" since it has only a pressure sensing system beneath the bladder to tell the trip computer when you've filled the tank. The Rav4, however, isn't a purpose-built hybrid; but a conversion of a standard Rav4 to hybrid drive technology. The gas tank is of conventional design with an in-tank fuel pump and variable resistance fuel level float type sensor. When working properly (which is should for many years) the float and potentiometer sensor is your best indication of fuel quantity remaining. If you fill when the low fuel indicator comes on you will get a feel for where your particular gas gauge is calibrated. It may not truly be "empty" till the gauge is below the bottom tick-mark on your gauge. Or it could be truly "empty" at or slightly above the bottom tick on the gauge. Variations in manufacture will show up here. Make a mental note and use your remembered notation to fill up before running completely dry. Don't rely on the miles remaining from the trip computer to be the ultimate limiting factor on your range.

Out in the big, empty midwest states, it's helpful to know approximately how much range you have remaining when "next gas 150 miles" signs are common. For most of us, this just isn't an issue so we don't really need or expect the miles-remaining value to be too accurate. Your mileage may vary (quite literally).
 

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I found on my previous hybrid (LEXUS CT200h) that the calculated mileage was always .2 l/100km lower than the readout. So if the car said I was getting 6.0 l/100km I actually got 6.2.
The tank was 45l. When the fuel light came on there was always 10l gas left. So I could go approx. 200km after the light came on!
I'd be curious to know the range on the RAV4 hybrid after the light comes on.
 

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In my 2013 Rav4, I would always drive until the light would come on then fill the tank. Invariably this would be between 12 to 12.5 gallons with a 15 gallon tank. I'm not sure yet how my 2016 Hybrid will track but it looks to be about the same 12 gallons to fill (except of course that the tank is 1 gallon smaller.)
 

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In my 2013 Rav4, I would always drive until the light would come on then fill the tank. Invariably this would be between 12 to 12.5 gallons with a 15 gallon tank. I'm not sure yet how my 2016 Hybrid will track but it looks to be about the same 12 gallons to fill (except of course that the tank is 1 gallon smaller.)
Umm... ya.. that's pretty standard for Toyota to turn the light on with 4 gallons left.

But how many miles have you gone when that happens?
 

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In my 2013 Rav4, I would always drive until the light would come on then fill the tank. Invariably this would be between 12 to 12.5 gallons with a 15 gallon tank. I'm not sure yet how my 2016 Hybrid will track but it looks to be about the same 12 gallons to fill (except of course that the tank is 1 gallon smaller.)
The gas tank on the RAV4 Hybrid is 14.8 gallons. :D
 

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2nd fill up today - I use a great iPhone app called 'Gas Cubby'. It calculates real mileage by inputting the odometer reading, cost/litre and qty of gas pumped. I always stop filling at the first click so every reading is consistent. Got 6.7 l/100km (35.1 mpg US) on 369 km driven.
 
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Discussion Starter · #18 ·
I use the Fuelly app on my Android phone. Their web site has bits of HTML code you can add to your signature on the forum(s) so your average MPG is constantly shown. Mine is a bit low right now because I've been driving around in the snow trying out the AWD-i system. Fuelly - Track and Compare your MPG
 

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I just setup my Fuelly signature - let's see if it works! So it does, but I left it in MPG - will now change it to what we're familiar up here in the Great White North - l/100km!

I use the Fuelly app on my Android phone. Their web site has bits of HTML code you can add to your signature on the forum(s) so your average MPG is constantly shown. Mine is a bit low right now because I've been driving around in the snow trying out the AWD-i system. Fuelly - Track and Compare your MPG
 

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2nd fill up today - I use a great iPhone app called 'Gas Cubby'. It calculates real mileage by inputting the odometer reading, cost/litre and qty of gas pumped. I always stop filling at the first click so every reading is consistent. Got 6.7 l/100km (35.1 mpg US) on 369 km driven.
Simple math can replace that app :wink
 
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