Life MPG

Be sure to record your 'life' meter before each service. Some techs may accidentally rest it while resetting the maintenance reminder.

 

You can also use Fuelly for that and you won't have to worry about it being reset. Check out the images in my signature. Log each fill up and it does a great job at providing stats. My 2010 has every fill up from when I got it. The 2014 does too but only one so far until tomorrow

 

Pen and paper notebook in the car for fuel logging, and a spreadsheet on a home computer, will do the same job.

 

Laptop and Excel in the car will also do the same job. So will writing on your hand.

Fuelly is easy to use and free, and can be done in one step. Also allows you to compare to other users as well as see other cars.

 

My Fuelly icon is pretty much lifetime. I started logging fillups within about 1000 km's of new, around 45000 kilometers now. In a spreadsheet. Then heard about Fuelly, and managed to restructure a copy of the spreadsheet to import all my entries in one go. And have updated fuelly and the spreadsheet religiously since.

I don't put much faith in the car's built-in records for a couple of reasons: first the mpg claims of the car are on average 8% optimistic (my experience). And I'm not going to rely on something that could be reset, or maybe lost with disconnection of the 12 volt.

One thing, the longer you keep records, the harder it is to budge the running total. Due to a recent lay-off I've been doing more of the driving, and I'm doing my level best to push the liters/100 km number down. So far I've managed to get it from 5.1 to 5.0, big whoop.

 

are we talking mfd or fuel up calc? my gen II was 6o mfd and 58 calculated through 40,000 miles.

 

I've been resetting Trip A at every fill-up (as I've done since the trip odometer was invented in the late 80s). My first half-tank worked out to 58 mpg and I thought "didn't get the tank filled up all the way". The last two were about 60 and 61 mpg. The MFD has been indicating mid-60s, so a little less than 10% optimistic.

The only caveat is that this has been during ideal weather conditions. I'm curious to see how far it will drop in the winter.

 

Get ready for that drop in the winter. I get around 50 mpg summer and low 40's in the winter.

 

Winter ack! At least with more miles on the car they do seem to increase MPGs some. My 2011 two was a ringer for MPG, my 2014 I have now struggles to break into the 70s.

 

51.016 on my factory Goodyear tires. Dropped to 49.887 after one year on Continental tires. Hand calculated.

 

^So is that your lifetime average, pushed down by the new tires? Grrh.

 

I'm going to suggest:

• A tripmeter - use for tank mileage
• B tripmeter - use for trip mileage and other experiments
• Fuelly or the EPA site - record tanks and share with others

You can calculate the lifetime MPG by converting each fill-up into gallons and use a spreadsheet to keep a running total of fuel burned. Divide into the odometer reading from the last tank and problem solved. The reason is many of us found over time how to optimize our Prius using the tripmeters for local experiments. But after 5,000 miles, the long term trend pretty well reaches an end value that only changes with seasons By 50,000 miles, even seasonal variations get lost.

GOOD LUCK!
Bob Wilson

 

Good points Bob. I had planned on doing just as you suggested. I only did tank calculations on my van, but wanted to do a little more with the Prius.

 

I enjoy using Fuelly to keep track. With this one I started including what the car says for mpg in the notes.

 

Oh, I didn't think of that, thanks for the tip.

 

I saw it in another thread people were reporting both numbers so seemed like it could be interesting to keep track.

 

I'm keeping track in a spreadsheet, so I didn't think of adding it to Fuelly for others to see. I also added the percentage of highway vs freeway driving when the amount is significant. There is a big mpg difference between 55 and 75 mph.