You may have noticed that I have not posted an 'MPG Review' post for three weeks or so. This is with reason. Actually, it is with various reasons. I fell ill with a nasty head cold, my wife has succumbed too, though in typical stoic woman style she has shrugged it off as "not that bad". To top it off, I have been thinking that my method of recording the Prius MPG is flawed.
Let me explain my thinking.
My method to date has been to note climatic and related data, record it in a table every week, as well as note the average MPG displayed on the Prius LCD display panel. Now, I have never pressed the "Reset" button on the LCD display. I just run the Prius, fill up with fuel when I need to and reset the odometer Trip A reading to zero. Every week I take my latest MPG reading. The removal of the Thule roof bars has led me to dig around a bit more since I expected there to be more of an evident 'step change'. Instead there has been just a gradual change. I did notice an increase in the miles per tank as evidenced by the Trip A odometer reading. Hmm, that is odd I thought. So I did a manual calculation based upon the distance covered with my latest tank of fuel. Bearing in mind I calculate in imperial gallons since I am resident in Scotland,I found that I was actually getting 55mpg, not the latest 51.2mpg as displayed on the LCD display. Of course, it becomes clear to me that the Prius readout is because it has been averaging the MPG since the last reset on the display panel button. Naturally, I will be changing the way I track and report on MPG from now on. I propose that with every fill up of fuel not only will I reset the Trip A odometer reading but I will reset the fuel consumption reading too. I think this will give a more honest and direct reading of the latest driving conditions and effects upon the fuel economy of the vehicle.
Wish I'd thought of this before but I guess this diary charts a journey of discovery ... and of my own stupidity! On top of this, it looks like I'll be refitting the roof bars (an easy job) in order to prepare for our holidays down south to England.