Partial Fill Screws Up MPG Calc...

[Draigflag]

I've confused myself with a partial fuel up. Didn't have time to fill the tank yesterday, so I just put £45 worth in. I added all the miles (500+) and the half ish tank of fuel and checked partial. My question is, how do I add my next fuel up? I reset the trip odometer again, but I'm only going to do half the miles now compared to a full tank. What data do I input next fuel up?

[JockoT]

I would imagine you would just enter the data as per any full tank. You can always edit it if I gives dodgy numbers.

[Draigflag]

Ok, I'll see what happens, if I remember correctly, the MPG calculation skips the next fuel up too if marked as partial.

[ember1205]

Originally Posted by Draigflag

I've confused myself with a partial fuel up. Didn't have time to fill the tank yesterday, so I just put £45 worth in. I added all the miles (500+) and the half ish tank of fuel and checked partial. My question is, how do I add my next fuel up? I reset the trip odometer again, but I'm only going to do half the miles now compared to a full tank. What data do I input next fuel up?

There are two fueling situations: You either fill the tank to the top, or you don't. When you enter the data into Fuelly, the ONLY thing you do differently is to check the "Partial Fill" box if you didn't fill the tank all the way. Everything else should be exactly the same as any other time, including if you enter the distance driven since the last fill (as opposed to always entering the odometer reading at the time of fill).

You will almost certainly have to edit the partial fill from a computer after-the-fact to return the mileage calculation to proper order (you don't change anything, you just edit it and save it). This is something that I -always- have to do if I don't fill the tank to get the system to correct calculate mileage afterward.

[Draigflag]

Well I did as you said, and in the table at the bottom, there is no MPG calculation as expected. But my average MPG in my banner and mini stats has jumped to 28 MPG. I'm not sure if/when this is going to work for me anymore as the fuel tank is so large and I can't afford to fill it all the time.

[ember1205]

Originally Posted by Draigflag

Well I did as you said, and in the table at the bottom, there is no MPG calculation as expected. But my average MPG in my banner and mini stats has jumped to 28 MPG. I'm not sure if/when this is going to work for me anymore as the fuel tank is so large and I can't afford to fill it all the time.

There are only two levels in a fuel tank that are correct 100% of the time - completely empty and completely full. In order to track overall MPG, you -could- use the empty reading, but that would be really hard to do as you would literally have to run the tank completely dry and that's simply not feasible.

That means you have to use full tanks to measure in between. If you aren't filling the tank each time, then you have to go off of average "in total" between two full tanks. Your tracked MPG in your banner will likely drift over time because you are filling infrequently, but the numbers should be accurate when you DO fill up (assuming that you make the manual edit as described here).

[trollbait]

Originally Posted by Draigflag

Well I did as you said, and in the table at the bottom, there is no MPG calculation as expected. But my average MPG in my banner and mini stats has jumped to 28 MPG. I'm not sure if/when this is going to work for me anymore as the fuel tank is so large and I can't afford to fill it all the time.

You'd have to basically fill the tank around the tank being just a quarter empty all the time.

[ember1205]

Originally Posted by trollbait

You'd have to basically fill the tank around the tank being just a quarter empty all the time.

Yeah, that's another approach. At least that would never require flagging a fill as a "partial" anymore. It takes more dedication from the owner, though, to never let it drop below a certain level before filling up.

[breddiskirmenzz]

A partial fuel up is when you don't fill the tank right to the top, example, you only put a gallon or two in because you want to use a cheaper filling station further down the road.