avg mpg calculation - Fuelly Forums

Click here to see important news regarding the aCar App

Reply
 
Thread Tools Display Modes
 
Old 04-21-2013, 01:41 AM   #1
Registered Member
 
Join Date: Apr 2013
Posts: 6
Country: United States
avg mpg calculation

I have entered 7 fuelups for my tdi diesel. I displayed total gallons used and calculated the mpg. 2553/81.02=31.5. I am using odometer so I subtracted the first fuelup 15.56=65.46. 2553/65.46=39.000. I still see an avg mpg of 55. How do you calculate the mpg? I know it will get better with more fuelups but I would like to know how you calculate it.

thanks
bob
__________________

rsdavis9 is offline   Reply With Quote
Old 04-21-2013, 02:34 AM   #2
Member
 
Join Date: Jan 2013
Posts: 55
Country: United States
Location: 40601
I only use trip miles to calculate MPG. Gallons used divided into miles driven gets it every time (example: 260.6 miles/7.43 gallons = 35.1 MPG). I don't find odometer readings useful for tracking MPG, although it is useful for other things like service intervals.
__________________

dtwjr is offline   Reply With Quote
Old 04-21-2013, 04:52 AM   #3
Registered Member
 
Join Date: Apr 2013
Posts: 6
Country: United States
odometer works fine because the trip = odo - prev odo.

What I don't get is how to start it off. The other advantage of odo is cant screw up by forgetting to zero or accidentally zeroing.
rsdavis9 is offline   Reply With Quote
Old 04-22-2013, 12:03 AM   #4
Registered Member
 
Join Date: Apr 2013
Posts: 6
Country: United States
I figured out how you calculate average. Basically you total all fuelup gallons except the first one and divide that into total miles tracked. The problem I was having is that you exclude other fuelups. If you mark partial you exclude those gallons and the next one after the partial(s). This is fine except for the fact if you use odometer then the miles of the partials still get included. I can envision a better algorithm(see below). Also anytime a fuelup has zero miles or other nonsensical numbers you also exclude that fuelup from the totals. The better algorithm is that if you mark partial still include the gallons but don't show the avg until you come to the next fuelup which isn't partial.
rsdavis9 is offline   Reply With Quote
Old 04-22-2013, 06:22 AM   #5
Member
 
Join Date: Nov 2012
Posts: 33
Country: United States
Location: Gainesville, FL
Partials should be calculated into the average as long as there is a total fill up some time after them. You will know what the average mpg is over the course of several partials because you still know the total number of gallons used and the total number of miles drive. You just wont be able to get mpg stats for the particular fillup if it's a partial because fuelly has no way of knowing how much gas you used, at least not until you fill it back up all the way.
waterboysh is offline   Reply With Quote
Old 04-22-2013, 10:19 PM   #6
Registered Member
 
Join Date: Apr 2013
Posts: 6
Country: United States
Yes that is the way it "should" work. But in my experimentation it doesn't work that way with odometer tracking.
__________________

rsdavis9 is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Fuelly iOS Apps
Powered by vBadvanced CMPS v3.2.3


All times are GMT -8. The time now is 01:32 PM.


Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.