[bug?] MPG calculations are wrong

[micheledt]

Hello,
it seems that there is a bug in calculating the MPG value.

If I set a fuel-up as "partial", then it does not immediately count towards the MPG value but it gets summed with all the contiguous partial fuel-ups.
The same should happen to the partial KM for each fuel-up, but that does not happen!
It seems like you calculate MPG by dividing:
last partial km / (sum of all litres in last partial fuel-ups).

You can check this in my logbook here:
Toyota Verso S (Toyota Verso-S) | Fuelly
where you see L/100km values such as
27,79 or
354,24

Please let me know.

[Draigflag]

It would seem you have some 80+ fuel ups where economy cannot be calculated. A partial fuel up is where you add fuel, but don't fill the tank, and therefore cannot input any distance driven values either. Are you using odometer to track?

[micheledt]

Originally Posted by Draigflag

It would seem you have some 80+ fuel ups where economy cannot be calculated. A partial fuel up is where you add fuel, but don't fill the tank, and therefore cannot input any distance driven values either. Are you using odometer to track?

Yes I am using odometer to track.
I thought a partial fuel up is when I partially refill my tank (but always keeping track of the odometer).
What do you suggest then?

Thanks


EDIT: this is the bug I am talking about.

You can see from my log for example that the calculated average L/100 is 20.48 because it is the result of this operation:
(26.861*2+27.172)/395*100
whereas it should be calculated
(26.861*2+27.172)/(395+515.01+468)*100
with all the KM!!!

[Draigflag]

I'm sorry I can't help, I'm not sure how the system works using odometer tracking as I use the trip meter. But it looks like there's alot of errors in your fuel logs, 8 pages of "partials" and then a few more pages where your fuel consumption is stupidly high. Hopefully one of the team can help you.

[micheledt]

Originally Posted by Draigflag

I'm sorry I can't help, I'm not sure how the system works using odometer tracking as I use the trip meter. But it looks like there's alot of errors in your fuel logs, 8 pages of "partials" and then a few more pages where your fuel consumption is stupidly high. Hopefully one of the team can help you.

Yes, to be as precise as possible, I mark "complete fill up" only when I actually top up the tank.
All the other fill ups, e.g. if I put let's say a fixed amount such as 50€, I considered them "partial fill up".
But there is clearly a bug in the calculations, or I am missing something...

[allanp]

As a new member found this information useful i admit the partial fuel up tick confused me. I assumed i would tick the box add say 20 litres and my odometer reading and fuelly would recognise and correct my total avr on next full tank. Will need keep a good check on that part of system

[micheledt]

Originally Posted by allanp

As a new member found this information useful i admit the partial fuel up tick confused me. I assumed i would tick the box add say 20 litres and my odometer reading and fuelly would recognise and correct my total avr on next full tank. Will need keep a good check on that part of system

Yes, according to the documentation (see New Fuel-Up Record)

*A Partial Fuel-Up is any fuel-up where you are unable to completely fill your tank. When this box is checked, aCar will not calculate MPG for that fuel-up until your next full fuel-up. The Missed Fuel-Up box allows you to account for a fuel-up that wasn't entered into aCar without throwing off your MPG. When this box is checked, aCar won't calculate your MPG until your next complete fuel-up.