800 mile per tank challenge

. . . so I came up with this explanation: Imagine I had an SUV instead and was getting 25mpg with it (probably a bit optimistic). With gas at $2.50/gallon as it was here today, in effect I'm paying 80 cents a gallon for gas for the Prius. At 50mpg in the Prius I'd be paying $1.25/gallon.

I'm also avoiding 2-3 gas stops per 800 miles, at 10 minutes? per fillup.​

Ok, I see numbers but even this one was a little obscure. Let me suggest you are trying to report the cost per mile as a function of MPG because I had to do the same for our Prius versus BMW i3-REx today.

At ~$2.50/gallon, a 25 MPG SUV is paying $0.10 per mile. A 50 MPG Prius is paying $0.05 per mile. An 80 MPG Prius like yours, pays about $0.03 per mile.

At ~$0.08/kWh, a BMW i3-REx gets a little over 4 miles/kWh so I am paying $0.02/mile. But there are two sets of free chargers near work.

If I stop by the free chargers for an hour lunch or coffee or an after work adult beverage or shopping anywhere within 1/4 mile, half of my miles are free. In effect, $0.01 per mile. The businesses are giving away 'free electricity' to attract well paid, EV owners ... who can buy an EV. They are not giving away free gas.​

Now today's penny has so little value, it may be a unit of currency too small to have an effect. Change it up to say a '10 mile commute' and the numbers become:

• $1.00 / commute - 25 MPG SUV
• $0.50 / commute - 50 MPG Prius (my Gen-3)
  
• $0.31 / commute - 80 MPG Prius (your Gen-4)
• $0.20 / commute - 4 mi/kWh BMW i3-REx (my plug-in)
  
• $0.10 / commute - 4 mi/kWh BMW i3-REx (my plug-in shopping at free chargers)

Carry three quarters, two dimes, one nickel, and one penny makes a great visual aid. Then point out, these are after taxes money ... you'll need another quarter for ordinary taxes and the penny for 'someone else.'

Bob Wilson

 

Thanks, but I really don't mean this to be a "claim" as much as a supporting comment that what I'm seeing is similar to what others have reported here. As we all know, the uncertainty in "g" makes it difficult to determine mpg accurately. And in any case mpg depends on so many factors. In some situations (for example, winter driving on urban streets, as in Boston, or on snow tires), 45mpg might be tough to reach.

As for "validating", if someone doesn't want to believe you they will keep finding new reasons to disbelieve your results no matter how hard you try. A typical one is "oh, you must be doing crazy stuff on the road". I learned this lesson when my astrophysicist brother in law and his cronies at a major lab in Berkeley absolutely refused to believe that I was averaging >100mpg (whole tanks) commuting to work in my MT Honda Insight, in the summer of course. Probably they were stuck thinking about steady state fuel consumption, a convenient scientific simplification which does not apply to hybrids, where the whole point is to alternate periods of zero consumption (battery, or coasting in the Insight) with judicious use of gas to propel the vehicle and recharge the battery. Pretty appalling that the very guys who should have open minds about data don't. The only alternatives were that the gas pump or odometer read wrong, or that I was fabricating data, also appalling considering that my brother in law had known me for 30+ years.

So these days I consider my mpg something for me to enjoy personally and don't worry too much about "validation". And if people like Dan Kraus or Bob Wilson or others post data here, I'll gladly accept it because it just seems like too much work to make up numbers, and for what gain? Sometimes when I get crazy high mpg for a trip I'll shoot a photo of it, but I'm just not going to bother photographing my tanks, posting to this or that website, etc.

 

87 Octane.

 

Back to back 800+ mile tanks. This one felt easier.
804 miles
11.076 Gallons of 87 octane (CA gas)
.036 cents per mile

 

Has that been tested on the Gen4? I wouldn't apply our old Gen3 numbers until someone runs Bob's out-of-fuel tests on the new generation.

 

I did drive 100 miles past the gas is low indicator and 75 miles beyond the DTE of 0 (same tank). I pumpled 11.148 gallons of gas at that point. (first click).

 

I can't emphasize enough that when 'tickling the dragon,' one should have a spare, filled, 1 gallon gas can on-board and your head and eyes on swivels. There are too many 'stove pipe' drivers ... way too many!

Bob Wilson

 

i carry two one-time use collapsed gas cans in my car at all times.

 

Third 800 mile tank in a row. Now that the weather is hotter, I have averaged 802 miles driven with 72.2 calculated Miles Per Gallon on the last three tanks (76.2 on the MFD). 11.113 gallons of 87 octane.

 

Did you keep your Insight?