I've been on 2 long distance trips, and notice when I reset the trip, either A or B, the average mph seems way off. For example, a 5 hour car ride, I basically was over 70 mph the whole way. Yet the average showed up as 61-62mph. What's going on here?
The average MPH meter counts even when you are standing still, based on trip time, so when you filled up, if you were standing still for a few minutes that will be the reason its lower than 70 mph, try reseting it while you are driving, and it will be much higher...
Blame it on math. It's accurate. When you slow down to 20 mph for a bit or stop, it really cuts into you overall average much like it does for fuel economy. I can't drive on the freeway for 48 miles averaging 50 mpg but as soon as I start climbing the hill near my workplace my instant mpg goes from 50-53 mpg down to 23-32 mpg over an 8 mile section of highway. This drops my average mpg to around 46 mpg. Now imagine if my instant mph was in the single digits for a short time. Maybe this is a bad analogy but it makes sense when I compare the two. My Scangauge says I average 57 mph during my morning commute. I drive for 2 miles through stop signs and stop lights. Speed never higher than 35 mph. The rest of the commute is 54 miles of freeway at 65mph.
Please try to do following senario... reset a trip meter and read the exact time after exact one hour later, read the trip mile and average speed. You wil see how accurate the average speed is. Ken@Japan
Watch the average mph reading when you are at a stop light. You'll see it tick down while you are sitting there. Or re-set it while you are on the interstate and watch it until you get off. If will show the speed you are actually driving for as long as you are driving it. The math works.
So you reset the trip meter after reaching 70 mph, and saw it read 62 before slowing to under 70? The point here is that this meter is not like bicycle calculators that count average speed only when moving. Prius counts that entire time the ignition is Ready, whether moving or not. If 5 hours after resetting the trip meter, it reads an average speed of 62 but shows you traveled 350 miles or more, then there is a problem. But if you traveled only 310 miles in that time, then the meter is correct. If you set the cruise control on the highway then reset the trip meter, the average indicated speed is likely to be 1-2 mph slower than the speedo because the later is biased high for legal and industry standards reasons.
3 days ago my monitor showed 4,0L on 100km, I did close to 800 km, them filled up tank, the difference was 0,33l on 100km (4,33l on 100km) its clise to 8%, its normal.
