partial fuel up...
 

im not sure i understand how fuelly deal with partial fuel up.
Could I, alternatively, DON'T register a partial fuel up, wait until the next full fuel up, then tell fuelly the total distance traveled, total fuel up volume, and an averaged fuel price. the last one will be less accurate but will this method give a better track of fuel consumption?

I think a good solution would be if Fuelly could just group a partial fuel-up and the following complete fuel-up together and show the mileage of that "enhanced tank", instead of not showing the mileage for both fuel-ups.

If you enter a bunch of partial fill ups, it will not show a mpg for the first tank that you completely fill up. That is because the mpg for that particular fillup is not known. However, it will still take the total mileage and gallons into account when calculating your averages and totals.

if you log your partial fuel up gallons only as a note you can just add the extra gallons in when you do a complete fuel up, the miles will be correct.

Does this make sense?

On a partial, should miles be entered and the trip counter reset though? Or enter a zero, then the full amount on the next full fill up?

If I happen to do a partial (which I very rarely do) I just combine it with the next (full) tank and don't enter anything. But that really messes up the theoretical 'range' thing, so I did only twice or so in the last 200+ tanks.

Same here. If I ever did a partial I would just add it in with my next fillup.