DJG
Well-Known Member
- Thread starter
- #1
So I just confirmed something that I thought I'd share as it relates to efficiency numbers that sometimes get shared and discussed.
The efficiency calculation in the tripmeters simply takes the distance traveled (which is shown to the tenth of a mile) divided by the rounded whole number of kwh used. So, what this means is that while driving, you can watch the efficiency increase regardless of the driving conditions, as you gain miles driven but the energy used doesn't change. Then, the KwH will roll up to the next integer, and the calculated efficiency drops down, and you do it all over again.
The takeaway here is that it's invalid to draw conclusions from, and especially share, efficiency stats from the trip for anything that is short distance, because it is bound to be wrong, and to a materially large degree. Just for math sake, below is the range of values you would see by distance driven:
These are set based on the assumption you get 290 miles out of 125 usable kwh of battery (approximately equivalent to Conserve Mode on the AT's), for an efficiency of 2.32. However, just before reaching that full range, you might be at 289 miles driven and 124kwh of energy used (as shown) before you finally get to 124.5kwh or whatever it takes to turn to 125 in the trip. Not a huge difference or deal, as the difference between 124 and 125 isn't too large percentage wise.
As you can see, at trips of only 20 miles or so, the efficiency number shown can be off by as much as 0.34 mi/kwh, because the difference between 10 and 11 kwh is 10 times as much as above. This gets washed out the longer you drive, so your total trip stats since delivery, or stats for a full battery drive, are "close enough for government work".
So just food for thought as you look at the Trip and interpret it or share results.
The efficiency calculation in the tripmeters simply takes the distance traveled (which is shown to the tenth of a mile) divided by the rounded whole number of kwh used. So, what this means is that while driving, you can watch the efficiency increase regardless of the driving conditions, as you gain miles driven but the energy used doesn't change. Then, the KwH will roll up to the next integer, and the calculated efficiency drops down, and you do it all over again.
The takeaway here is that it's invalid to draw conclusions from, and especially share, efficiency stats from the trip for anything that is short distance, because it is bound to be wrong, and to a materially large degree. Just for math sake, below is the range of values you would see by distance driven:
These are set based on the assumption you get 290 miles out of 125 usable kwh of battery (approximately equivalent to Conserve Mode on the AT's), for an efficiency of 2.32. However, just before reaching that full range, you might be at 289 miles driven and 124kwh of energy used (as shown) before you finally get to 124.5kwh or whatever it takes to turn to 125 in the trip. Not a huge difference or deal, as the difference between 124 and 125 isn't too large percentage wise.
As you can see, at trips of only 20 miles or so, the efficiency number shown can be off by as much as 0.34 mi/kwh, because the difference between 10 and 11 kwh is 10 times as much as above. This gets washed out the longer you drive, so your total trip stats since delivery, or stats for a full battery drive, are "close enough for government work".
So just food for thought as you look at the Trip and interpret it or share results.
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