How to Track Lifetime MFD (Prius 2010)?

[wfn]

This may turn out to be a dumb question, but here goes: Does the 3G Prius automatically track lifetime average fuel consumption (a.k.a. MFD), and if so how? Or is that something I have to do via spreadsheets?

If there is no automatic tracking, then what is the "best practice" for using the Trip meters A and B? Assuming I just use B for fun, should I reset A every time I fill up (but only after I have carefully noted the MFD)? And if I accidentally forget to record average fuel consumption even once before I reset, have I lost the ability to track lifetime MFD?

Note: I plan to record and track actual fuel purchases and distance, but I'm also interested in tracking the Prius' stated consumption (and comparing the numbers).

Anyway, I'm obviously a bit confused here. Can someone set me straight?

[Sandy]

Mine has been reset many times i use the banner below

[Paradox]

You have to use trip A or B and not reset one of them from the day you bought the car. Then the problem becomes that (I think) at 9,999 miles the mileage will just return to 0. The MPG will probably keep running its tally but one will have to know how many times they have hit the 10,000 mark.

[Bobsprius]

I have a question along the same line. My BEST MPG mileage shows 47.2, but in some of the graphs I see where I am at 55 and better. My trip A which shows my overall MPG at 53.7 right now still never updates the BEST MPG numbers...Is there something I should be doing or reseting to make the BEST MPG numbers accurate??? It has not changed from the 47.2 MPG?????

Sort of confused on this one..any help appreciated! Thanks

[a priori]

I'll note my uses of the trip odometers and how I do the calculations, but please don't consider this anything other than my way of handling it (though the calculations DO have to follow certain mathematical principles).

I use my Trip A for discrete trips. These have been as short as 13.6 miles and as long as 849.5 miles. I change this Trip A each time I change driving style or location -- always when changing from urban to inter-urban (city to highway) and sometimes for other reasons. Independently, I track my tanks on Trip B, resetting that odometer everytime I fill the tank.

How do I determine lifetime MPG from the MID? I write down all data each time I change a trip odometer. I also write down each gasoline purchase. I have a very large spreadsheet where I keep the data, and in that spreadsheet I determine the lifetime city, highway and overall mileage from the MID readings (see my signature below). I also track the actual purchases and the cumulative MPG from that measurement. The differences between MID and calculated end up in a table. I have shown this table, periodically as it is updated, in another thread that is a Sticky in the GenIII Fuel Economy forum. Here's the link to my latest post in the sticky 2010 calculated vs. computer MPG - Please post your results.

[wfn]

Thanks everyone, for your feedback/suggestions. I think I'll go with the "a priori" approach. [My only nervousness is that one day, I'll forget to write down the MID reading before I reset Trip B ... and then I'll have lost my ability to track/report lifetime MPG based on the MID. Wouldn't it be great if the Prius had a Trip C? I'd use that for lifetime tracking, as suggested by Paradox.]

Anyway, "a priori": are you willing to share your spreadsheet? I've been working on one, but I'm sure yours is better. I'm good with Excel, so you wouldn't have to explain it to me. [If you're not willing, no worries though.]

Thx.

[a priori]

Originally Posted by wfn

Thanks everyone, for your feedback/suggestions. I think I'll go with the "a priori" approach. [My only nervousness is that one day, I'll forget to write down the MID reading before I reset Trip B ... and then I'll have lost my ability to track/report lifetime MPG based on the MID. Wouldn't it be great if the Prius had a Trip C? I'd use that for lifetime tracking, as suggested by Paradox.]

Anyway, "a priori": are you willing to share your spreadsheet? I've been working on one, but I'm sure yours is better. I'm good with Excel, so you wouldn't have to explain it to me. [If you're not willing, no worries though.]

Thx.

You'll be able to find a way to keep the info straight. I keep multiple records: I write the MID info on the receipt, and I write down both A and B in a small notebook I keep in the car. The overlap often gives you the information you need should you forget to reset. In any event, I write down my Trip B right when I stop the car at the gas station. I check it when I write the numbers on the receipt, and then I zero out. Finally, I write the info in my book. Every once-in-a-while I'll bring the book in and fill out the spreadsheet.

Speaking of the spreadsheet, please PM me and leave an email address for me. I'll be pleased to share it with you.

[vincent1449p]

Originally Posted by Paradox

You have to use trip A or B and not reset one of them from the day you bought the car. Then the problem becomes that (I think) at 9,999 miles the mileage will just return to 0. The MPG will probably keep running its tally but one will have to know how many times they have hit the 10,000 mark.

Just curious why you need to know how many times they have hit the 10,000 mark? Doesn't the Odometer provides the info.? Let's say the car has 12 miles on it when you collect it from your dealer, you reset either one of the trip meter. Your trip meter will always be 12 miles less than ODO. Am I missing something?

[Omni-TaG]

Has someone had the idea to ask the dealer if the shop computer could be abble to retrace those specs about lifetime consuption ? Maybe, when i reset A or B, that somewhere inside in-board computers there are these infos preserved ?