I was just thinking about range tests published here and elsewhere Range is really kind of a 3 dimensional graph where speed/temperature/SOC interact People will drive whatever speed they drive, but really, if you are actually concerned with range, are you driving 70mph? I mean I drive 70 mph, more, but if you are on a trip where it matters, is that the smart move? ON a 500 mile trip it amounts to a bit over half an hour. Yet it can have a significant effect on range. I would think in the bell curve of trip lengths, the most common trips are obviously under the range of the EV. So the real question is more can I make the 2 hour each way to grandmas without charging? If it took you 8 minutes longer to get there, but it meant you could do it without stopping, isn't that the thing to do? It doesn't mean you would drive 50 since the time gets much longer and the return diminishes. But the ability to not stop at all, or maybe plug into 120 when you get there to add a few miles as insurance, that is a real thing I also don't see the point of the drive it till it dies routine. Sure, it is intellectually interesting to see how much reserve a car has, but that is not really a useful driving measure. Do we really need to ponder EVs limping down the shoulder as a viable option? Why not drive them to an agreed upon battery level? Like 10 percent , or 5 percent, something a person would actually do. Then extrapolate from the battery level and actual miles/kwh used to come up with a range. Unless we are finding some hidden range in certain cars, I really don't see that it is particularly less accurate. IF you drive a car with an approximate range of 230 miles to 5 percent left, the total error must be less than 5 percent of range, in fact it is most likely within .5 percent of range[10 percent of the remainder] I would think this is much smaller than all the other variables. Example: Drive a car that you think will get about 230 miles range until it hits 5 percent battery remaining. It is 219 miles. That 5 percent would most likely get you about 11 miles down the road 219/95x100=230.5 Are you likely to get 20 [highway]miles out of that 5 percent? No Are you likely to get 1 mile out of that 5 percent? No Might you get as much as 15 or as little as 6? Absolutely 2 percent I mean, really, close enough, as I said, smaller than the other variables. If you get reports that a Tesla will get huge miles after it hits 5 percent, or the Kia drops to zero right after it hits 5 percent, this is need to know information. I am not trying to be hyper critical of people doing this important work, data is valuable, and not everyone can just drive around. Data can become information, information can become knowledge......
A former Prius owner/operator, my study of the EPA metrics revealed the need for: Standard Day (a Range) - target is 68 F but in real life, anything from ~55 F to ~85 F works Constant speed 63-64 mph - as speed increases, the aerodynamic drive increase can be used to adjust I can appreciate the desire of some to choose a different speed and temperature range. But the exact protocol for an EPA range test are well defined and include getting the roll-down coefficients. It pains me to see imprecision in claimed range tests. Bob Wilson
I think the issue is the EPA 'highway' test uses very little highway, which does not have as big effect on ICE cars as EVs. ICE cars get worse mileage at low speed so it is a wash as to whether they were losing mileage from driving 80 mph or 30 plus the 'range' was kind of a secondary thing for ICE cars so no one cared if it was that accurate.
Let me suggest a more technical forum: https://ecomodder.com/forum/ As a former Prius owner, these folks have an engineering bend which means you can research specific issues. I found this very helpful. For example a thread I'd started a long time ago: https://ecomodder.com/forum/376539-post1.html Bob Wilson
The thing about tests that are intended to be used for comparison is that a standard protocol for testing has to be set. Without a standard protocol you don't have data, you have anecdotes. Gene 2020 Honda Clarity Sent from my Pixel 3 using Inside EVs mobile app
Acceleration rate, curves, humidity, how clean the vehicle is, tire condition, regen setting, and on and on. Gene 2020 Honda Clarity Sent from my Pixel 3 using Inside EVs mobile app
Of course there are a lot of factors, some large some small. Regen means little steady state, humidity would again be in the smaller effect. Obviously noting these things would eventually show which assumptions about range are correct So much info is available now compared to 30 years ago, it would be pretty simple to figure out the altitude rise and drop on a given route.
Which is why I don't care about stated range, using it only as a comparison tool between cars. I hate statements about how much range can be obtained in an hour of charging, because it's a useless number that is based on idealistic testing. I think in terms of X% of battery and SoC instead.
Well I am not talking about stated range, and while all tests are flawed to some extent, it is not impossible to test things in a way that is rational and comparable between cars. The 70 mph tests are a 'thing' but to some extent, in my opinion they miss the mark in several ways
