Distance to Empty - A slightly better system

I've ignored DTE for as long as I've been driving the car.
It's even more inaccurate than the MDF's estimation of your fuel efficiency.....at least for the G3.

However (comma!)Prius drivers do love to sweat the small stuff, and this just gives them something harmless to worry about.

It's just not that hard. Either drive until the fuel gauge blinks and fill the tank????
Or....don't.
Either way? Life will go on.
There are people who regularly fill when the gauge gets below half (juuuuuust to be sure!)
There are people who regularly fill when they get to 11.8999999999999999999999 gallons consumed.
You know what?
I have heard where the G3 (and G2's and G1's) have been run out of fuel during my stay in these hallowed halls...more than once.
A lot more than once!
You know how many G3's I've heard about being damaged by idiots trying to get into the 800-mile club?
None.
Go down to your local Toyota dealer and ask them if they replace a lot of fuel pumps because hypermilers are burning them out.
Betcha they give you the Whiskey-Tango-Foxtrot??? stare.


Like the OP, I pay attention to the fuel efficiency of my cars by habit.
Not because I love hugging bunnys or picking tree bark out of my shirt pockets but because usually if a car is running efficiently then you don't have to spend money on fixing something or having it fixed.
So....like I said earlier.
It's just not that hard.
Fill the tank.
Reset one of your trip odometers.
Drive until your mileage on that trip is 10x the efficiency that the MDF is displaying.
Refill. Calcuguess your efficiency if desired.

-or-
Drive until the MDF says you need gas.
Refill.


Done.
Life is waaaaaaaay to short to sweat the small stuff!
.

 

Totally unrelated but I always love reading your posts, ETC(SS)!

Thanks for the tip, Codyroo. I've always started sweating bullets when my last little blip starts blinking at me on the fuel indicator only to find out I only fill 9.2 gallons. I think multiplying my consumption x 10 will get me a little further without risking actually running out of fuel (even with the 3-5% difference I'm noticing in the reported mpg and calculated)

 

I'm in agreement. I've found that the 10x method works quite well. This gives you a reasonable amount of reserves left in the event you need to push it but allows me to postpone filling up for one more day. Since I have to fill up twice a week on average the extra day is nice.

 

"I think the Consumption X 10 is a useful calculation because it is simple to do and gives a slightly better estimate of your DTE."
" In looking at my records, when my displayed value x 10 was nearly equal to my mileage for that tank, I've found that I put in about 10.5 gallons"

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I must say your 10x method works quite well in my experience too. My last tank was the same as your records show of about 10.5g.​

62 dash, 618.2m, filled up 10.578g​

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Edit: Want to add if anyone is interested. Blinking warning light came on at 551 miles for that tank with 26 miles for MTE.​

MTE was at zero at 569.7 miles which I drove another 48.3 miles after MTE=0​

As stated above I used Codyroo's Consumption X10 and filled up 10.578g.​

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For my 2010 Prius III - the Cons. (MPG) estimation is about 2 to 4 mpg more optimistic most of the time. on my last 800 mile plus tank I normally get the first beep warning at about the 660 miles mark and the distance to Empty(DTE) reaches zero at about the 686 miles mark. With respect to my first 800 mile tank, my MFD cons. was 73.4 mpg which computed to 71.1 mpg when the 11.252 gallons of gas was taken into account. My Prius probably had atleast half a gallon of gas left. The method I was using to determine my range at that time was based on a rule I got from Bob Wilson that said that at the time of the fuel gauge nearing empty warning beep that I would have about 2 gallons left. To be on the safe side I use (CONS.-3)*2 to compute my range after the first beep which was (73-3)*2= 140 miles. I then took 660+140=800 to compute my safe range - which is why I didn't push it any further than I did.

 

For my purposes, the FLV Xgauge programmed into a ScanGauge is more useful than either DTE or Cons X 10.

While FLV nominally reads the same thing as the fuel gauge itself, it has an extra digit of resolution. I.e. where the dashboard gauge pips are roughly whole gallon increments, FLV reads in tenths of a gallon.

And FLV is a real fuel level, so it doesn't get confused by the highly variable conditions. My current tank started at just 47 mpg on a wet windy night, but a warm dry trip to Olympia and back today, 150 miles, produced 65 mpg. Differences of that size corrupt both DTE and the ConsX10 rule.

FLV does have its own vagaries. It doesn't filter out sloshing in the tank the way the dashboard gauge does. And its zero point reference does not match up with the actual bottom of the tank, nor the flashing pip. In fact it doesn't even go to down zero, but stops at 0.7 units. But with some observation and experience I've figured out what low tank numbers I'm comfortable with.

 

I have to agree that using your system of 10x or 11x is by far the best way to figure out how many miles you can go.

Personally the furthest I've gone on a tank yet is 10.4x and that took me to almost exactly 11 gallons. Next spring you can bet I will be doing 11x when I go for a 900 mile tank.

 

I agree with your system of 10X the CONS display. This pretty much agrees with my observations also.

Having said that I always fill up at 2 bars remaining and have never had to use the DTE measurement. But in the case of not being able to get to a gas station I will use this system.

 

If CONS is configured in litres per 100km, it displays fuel consumption rather than fuel economy. This helps determine how quickly you are draining the tank.
Given a 45 litre tank, if the CONS is a true 4.5l/100km you'll get 1000 km (622 miles).
5LHK gives 900km
5.5LHK gives 800km (820km, actually)
6.0LHK gives 750km
6.5LHK gives you reason to ask what's going wrong with your fuel consumption!

 

Going 11x would scare the bejeezes out of me. IIRC once a Prius runs out of fuel and shuts down - You can't just fill it up with 2 gallons of gas and restart a Prius up again - you need a jumpstart your Prius at the dealership. I really don't want to go there. That being said - when the Prius get down to less than half a gallon of gas left - that tank sloshing is really important factor in keeping your Prius running. FYI when a Prius is going uphill the Scangauge FLV reads a bit higher than when the Prius is going downhill.

 

I'm one of those that gets REAL concerned when my remaining miles on this tanks says "0". Of my 64 fill ups the highest one was 9.98 gallons. When I had my 2008 Toyota Prius, I accidentally ran out of gas once. We had arrived at Walt Disney World at night with nearly an empty tank. I thought I'd fill it up on the way out of town. We wound up using the car a couple times while there and I didn't think about it. Then the dreaded red "!" appeared and I was out of gas. Not something I want to repeat.

 

Yup.
That's about right.
Subtract 3-MPG from the goofy MDF SWAG, and you're just about right on.
Great mileages! You got me beat by about 5.