Partial fill up problem
 

The partial fill-up system does not work well umless I totally misunderstand. E.g. I do partial fill up and check the box, no MPG appears which is expected. Next time I fill up completely and don't check the box, still no MPG. Why? Only on fill up after that is MPG given. And manually calculating the MPG given after partial fill up is to me incorrect. Can anyone confirm? Is the system supposed to add up the total fuel and total distance during partial fill ups or does it ignore non fill-ups?

Once marked, Fuelly won't calculate MPG for that fuel-up or the next. However, your partial fills will contribute to your overall average MPG.

Fuelly's calculations rely heavily on you filling your tank to the top because it uses the difference from full to calculate fuel economy on individual fuel-ups.
More info here: Why do I have to fill the tank all the way up every time I buy fuel?

Why not just add the previous partial mileage and gallons consumed to the next fillup to get the number for the two combined? I wager that's standard practice for most anyone who tracks their mpg on their own.

If I just need a few gallons to give me time to get to my preferred gas station, then I want the mpg for those few gallons and then the full fillup when I next get one.

+1

I don't understand the reasoning behind "suspending" the calculation of MPG. If I start with a full tank, add only 5 gallons for the next three years, and then fill the tank, it's perfectly reasonable to still be able to calculate the MPG over that time. We know the total miles traveled and the amount of fuel used between the full tanks.

I agree with how the system currently works. Assuming you are driving to completely dry empty, and then are adding 5 gallons each time, it's an incorrect value being returned. If you're lucky enough to be able to hit empty dry at the pump each and every time, though, you might want to consider investing in lottery tickets. Otherwise if you're not dry empty, you might have used .5 extra or .6 fewer gallons every few fillups and eventually you will just run dry while having also gotten incorrect readings for the last ... 3 years.

Calculations don't work based on the amount you put in, it's about hitting the same starting point as the previous time, or as practicably possible, in order for the calculation to be correct.

I believe you completely misunderstood my point.

Assumptions: 15 gallon tank, initially full.

Drive 250 miles
Add 5 gallons, partial fill - no calc
Drive 100 miles
Add 5 gallons, partial fill - no calc
Drive 100 miles
Add 12.5 gallons - CALC NOW

There is absolutely no reason to have to do a SECOND full tank in order to get MPG. 450 miles driven on 22.5 gallons of fuel. 20MPG.

You started with a full tank and mileage can be calculated IMMEDIATELY upon the next full tank, regardless of how many miles were driven in between and how many gallons of gas were added. All that matters is that you only calculate between full tanks, adding everything in that occurs in between.

Why do I have to sit down and do the math instead of Fuelly doing it for me in this scenario? Why does there need to be a THIRD full tank (started with a full tank, added a full tank, but it won't calc until the next full tank - and only if it occurs immediately after the second full tank)?

I understand not being able to calculate the MPG for a partial fill... Makes complete sense because you don't know how many gallons relate to how many miles. But, once you have a fill up (full tank), you can calculate MPG using everything that occurred since the last fill up. And, Fuelly won't do this.

Yup, that makes more sense. :)

I agree. You have all the information you need to calculate the MPG when you finally don't check "Partial". What I've done is to not enter the partial and add the gallons when I do fill the tank. I shouldn't have to do this!

wow, I couldnt figure out what was going on with my fuellings of which I have several partial ones recently, until I came to the forum to see what I was doing wrong.

This is a MAJOR shortcoming and really renders this application useless!!

this really needs to be fixed.

Not being able to calculate mileage with a partial fill makes sense - there's no way to tell how many of the miles driven by the last fill up used how many gallons of the partial fill. If you drove 200 miles and put in 1 gallon of gas, what does that mean for MPG?

The issue is that the partial fill(s) are not added together from the last fill up to the current fill up with all miles in between used to compute an average MPG over that duration.

I feel there should be a "Current MPG" that shows the most recently calculated MPG based on a complete fill up. If that calculation also takes into account partial fill ups, it should appear in a different color or have some other sort of "asterisk" to it.

Agree that it should not calculate for the entry of the partial fill but the next complete fill it should add those 200 miles and that gallon of fuel in the calculation.

Come on, Fuelly!!! The masses have spoken! :)

If nothing else, maybe we could at least have an OPTION to choose whether the system will do cumulative MPG calculation using partial fills in between complete fills.

I just said this in another thread. This is a major shortcoming for Fuelly. It doesn't render the app useless, but it would do so for someone that didn't fill up all the way often. Each time you do a complete fill up, your MPG from your last fill up to the current should be calculated and added to the table.

Are you listening Fuelly? You just did "a major behind-the-scenes renovation", so why is this simple math problem still here? It's not like this is calculus. It barely qualifies as algebra. It's fourth grade math.

The "renovation" entailed converting the website from ColdFusion source code into PHP source code. With this process, our goal was to exactly duplicate the existing functionality. Only after doing this and having everything settle out, are we moving on to expanding the website's functionality.

As to the partials fuelup debate, we are discussing how it can be changed and who would rejoice the change and who would not rejoice at the change.

I've seen a lot of complaints about the way partials are handled. This is what I think most folks would like to see. Instead of the partial and the next tanks not calculating, it would be nice if this happens:

No calculation for the partial tank. The next time the tank is filled, the system will add up the partial tank's fuel and mileage to the full tank to give a MPG calculation at the very next full tank.

Provide a "switch" to either use the new calc method or not and ALL will rejoice (or at least not complain). Seems a pretty simple option.

Plus - users LOVE choices. Give them multiple ways to track and calculate MPG and they will ALL smile bigger because you've given all of them more control.

I cant see how anybody would 'not be rejoiced' about using partial fills in the calculation?

The whole point of Fuelly is to get a good record of the fuel consumption and MPG's. Surely anybody that is interested in that would want to see partials included. I cant think of a single reason why it would be beneficial to not include the partial fill information, of course when the user fills up completely/full.

Am I missing something? Gas Cubby, which I run in parallel does include partials.

The partial fill information is used right now in the lifetime average for the vehicle. No calculation is done immediately because what happens when you drive 400 miles and only put in 5 gallons? That will really throw off the numbers for most cars.

Jay,

I think that you'll see from this thread that we all agree that you can't calculate MPG based on a partial fill. That isn't what we're asking for, though.

Full tank
+ partial fill
+ partial fill
+ Full tank
= IMMEDIATE MPG calc going back to the last full tank. It's possible, it's reasonable, and it's desirable. We don't want that info "only" associated to the lifetime info.

I have brought up that suggestion to the programmers. Their focus right now is to just fix issues related to the transition to a new platform, once that is taken care of they plan on working on refinements and new features.

I am a computer programmer myself and I have worked with both ColdFusion and PHP. I can understand why you'd want to switch, makes perfect sense. However, this little issue is not a major item. It's something any programmer worth his salt could fix in a day, probably less. Also, this is really more like a design flaw than a feature, something you'd want to fix quick. Nobody's going to regret getting more data. The whole point of your website is to provide the users with more data.

Plus, you've got to consider that a lot of people don't fill their tanks all the way up very often. Back when I was young and didn't have a lot of money I'd only fill my tank all the way up occasionally. I'd almost never do it twice in a row, so your website would have been useless to me. Think of this as a way to expand your market.

Come on, make the fix. You'll be glad you did and so will your users.

LOL, thanks for the passionate feedback about this feature. We will address partial fuel-ups in the near future.

Am I the only one holding my breath that this will get fixed soon? Turning purple here!

With the price of fuel and the fact that my 4x4 takes 80l, I do partial fuel-ups most of the time, only on long trips will I fill the tank. I have not had a proper calculation in months.... stats and graphs becoming useless.

Yup. The users feel this is an issue, but the developer sees it as working as designed. Breathe... It isn't worth turning blue over. :)

When Gassavers was separate, the fuel log program didn't allow for partial fills at all. If you did a partial fill, you added those miles and gallons onto the next fill up you.

Until the when/if that partial fill ups gets addressed here, you can do it that way and not do partial fills through the site.

I have mentioned this in the past. It seems common practice in the states to fill up every time for most people. And yet I can't think of anyone who fills their tank here at all, it's an expensive thing to do.

I've made a change to show the MPG of a full fuelup following one or more partials. It may take a few hours for your car to be updated as all cars are currently being processed. You can note such a fuelup with the small circled i icon following the MPG. In the meanwhile, you can force the update by just editing and submitting one of your existing fuelups, or by adding a new fuelup.

Attachment 1713

That's great Freddie! What change did you implement? Does it add up all of the partials and mileage and post that calculation?

Doing the math of the sample he posted, that's exactly what he did... And exactly what we've been asking for!

Nice! :Thanx:

Yeah! Thank you very much! This rocks!
Usefull stats!

Yeah! So cool. Now Fuelly does the math for me. Thanks for getting this done.

Hello! Im new to this. I have a question. Is this considered a partial fill up if when my tank goes down to the half mark and I fill it up fully?? I live in the north east and its too cold to let my tank go fully empty. So my last two uses on this app have been added this way. All suggestions welcomed ! Thanks

No.

A "fill up" is when the tank is full. It doesn't matter how much was added, just that it is now full. Record the gallons added.

A "partial" is when the tank is not topped-off. Ie, "$10 worth", but it didn't fill the tank. Record the gallons added, and check the "this is a partial fuel-up" box. The next time the box is not checked (a fill-up), Fuelly will add up all the gallons added since the last fill-up, and calculate a MPG, notated with the "I" icon.

Thanks!! Appreciate it!