Best way to track mpg mileage (with dash info display) on 2012 Prius Std?

you have to reset one of the trip meters per tank, and leave one for lifetime.

personally, i just record each fill up and miles driven. some like to put the info on fuelly.

 

Use trip A for tank to tank fill ups and reset / record info each tank.

Use trip B for your lifetime MPG tracking, thats what I do.

 

I use Trip A for each fill-up and Trip B for each trip we take. They compute mileage based on miles driven since the last time they were reset and it has no relationship to how much fuel you actually pump, it's based on how much fuel it "thinks" you've used based on some flow sensors or something. It's computes on the high side, so if it shows you're getting 50 mpg, you're probably getting 47-48. Therefore, many of us also record the mileage/gallons and manually compute the mpg for each fill-up. I keep a spreadsheet so I can compute both fill-up, trip and lifetime mileage manually.

Even though inaccurate, the CONS display is useful to see how you are doing as you drive. You can watch the display and see how various routes/sections of highway or driving techniques affect the computations. If you don't care about actual mileage, the CONS number is as good as any. Heck, even the manually computed mileage is only as good as the gas pumps and we all know they don't pump the same amount of fuel when stopped at first click and it's never a good idea to top off, not only because of spills, but because it could damage some of the emissions equipment. Over time these minor variables don't have much of an impact and most people don't really care if they are getting 50, 48 or 48.3 mpg as long as it stays relatively consistent.

 

I leave mine on the option that displays instantaneous MPG as it gives me feedback so I can somewhat adapt my driving technique. If I'm getting 15 MPG while accelerating up a hill, do I really need to be accelerating, as an example.

Pump shut offs are so variable, I've seen as much as 28 MPG differences in consecutive fillups. But over time, things smooth out to my remarkably consistent average.

For tracking long term trends and average MPGs, I fill up, write down on the receipt the odometer reading, and enter the resulting figures (o-reading, gallons, price, comments) into fuelly.com and it gives me all sorts of statistics, graphs, etc that becomes increasingly meaningful over many fill ups. As well as the info that goes in my signature here.

 

I use A for tank and B for experiments. For total MPG, Fuelly - Track and Compare your MPG or the EPA web site Fuel Economy works.

There is a systemic error that I traced to the tire diameter. By choosing replacement tires whose revolutions per mile corrected the error, everything measures true. Use a GPS and/or mile-markers on a long trip to figure out the tire diameter error.

Bob Wilson

 

if you reset one of the trip meters, it displays a running average mpg. when you fill up, you have to reset it to zero and start again. you can leave the other trip meter for lifetime average if you want. but the car does not keep anything in memory. if you take it in for service, they might reset them, and you lose everything. if you disconnect the 12v or it goes dead for any reason, you lose them.