WetEV said:
GRA said:
WetEV said:
No, not data, it is just a guess. Why do people call it a Guess-O-Meter, after all?
Because the Leaf's DTM was notoriously inaccurate,
Any and every "DTM" (DTE?) is a GOM, for not one of them knows the future. What's the weather going to be like? What's traffic speeds going to be? How are your driving habits going to be today? Accidents? And so on. The GOM can't know any of these, accurately, and so must guess. Sure, there are better and worse GOMs, but they are all GOMs. Sure, route-based can be better, and could add in web based weather prediction, and so on. Still a GOM. Could be AI based, and observe your schedule and listen to your phone calls to guess at your mood, and thus how you might drive and to where. Still a guess. Still a GOM.
Yet some DTEs (DTM was a typo) are considerably more accurate that others. Some even take account of how you normally drive (aggressive/normal/eco). And some may be accurate enough in the real world, given its variability compared to a lab, as to no longer be GOMs for practical purposes. Personally, I'd consider that point to be +-5% accuracy, maybe as much +-10%. Or you can have something like the Bolt, which gives you high/median/low estimates, and you can pick the one that from experience best matches your driving in given conditions.
WetEV said:
GRA said:
Was the effect of the small variability in real-world conditions so great that it alone was able to overwhelm the 21% greater efficiency (16% Hwy, both EPA lab tests) of the RWD EV6 compared to the AWD Ioniq 5, or was AC vs. fan the major contributor to the difference? My preliminary conclusion is that it almost certainly was.
You would get rather more respect if you bother to verify before writing. Run the test at least twice, and see if you get the same results. Make sure you are correct. Read some other opinions before writing your own. Listen when people disagree rather than just keep pushing the same point out over and over and over again.
Looking to rent the EV6 again, if the weather doesn't change too much. It'll be cooler, but I intend to do the run without AC this time in any case to see if I get a significant range bump. The cooler temps usually mean the air's denser (assuming no radically different high or low pressure), so if anything the drag effect should be greater. Which leaves similar winds, and that's harder to find this time of year than a month ago. Then there's speed. But the ID.4 drive comes first, and then I'll see if I can squeeze another trip in with the EV6 before we get the first snow and they close the road for the season.
As to listening before pushing the same point over and over again, how about taking your own advice? Oh, and provide some data of your own.
WetEV said:
Data requires measurements carefully made to avoid fooling yourself, always the easiest person to fool.
Uh huh. How about providing some?
WetEV said:
GRA said:
WetEV said:
I rolled down the windows, which would have a larger impact on range at usual speeds than running the fan, and the GOM didn't change at all. Why not?
Obviously, the algorithm in your car doesn't immediately detect whether the windows are down or not and factor that into its calculation. It obviously _does_ immediately detect whether you've got A/C on or just the fan, and factor that in.
Obviously. The fan isn't a major power draw, and should have far less than 1 mile impact on range. The windows should have a large impact on range, and are not considered. It's a GOM.
Sure, the fans maybe 30W or so (found some data on an ID.4 forum). But while a GOM which doesn't detect whether or not the windows are open won't change the initial, instantaneous range estimate, it certainly will detect the greater energy use due to the extra drag of open windows as the trip continues, and can/should update the range estimate due to that effect. Which is totally different from the info available about AC energy draw, both initial and long-term. The question in that case is whether or not the DTE's initial range prediction when using AC is based on known AC energy use over time, or if it just works the same way as if the windows are open, i.e. based solely on actual usage as you go.
WetEV said:
GRA said:
WetEV said:
100 ICE trips don't teach much about EV driving.
To a point that's true, but they do teach about condition variability, i.e. the effects of terrain, winds, and temperature/density on range.
Most ICEs didn't have a GOM. Even where they do, most drivers seem to ignore it. Even if observed, the energy use of an ICE isn't the same as an EV.
Certainly not identical, but that's not the same as saying that terrain, HVAC use,air density, winds etc. won't have the same type of effects; the magnitudes (for heat, say) may be very different. I've never had a GoM in any car I've owned, but I can tell you to an accuracy of 10% or better what kind of mileage I'll get in a variety of common conditions. Or uncommon, FTM. For example, the worst highway trip mileage I ever got in my Forester was while carrying three people and luggage in cool conditions, with intermittent heavy rain showers and strong, gusty headwinds - 26.5 mpg. And the best I've ever gotten was 32.0 mpg, cruising along very flat freeway at 70 (I-5 IIRR, I'd need to check), just me, calm, warm day, no AC. More typically I get 28-30 mpg (EPA HWY is 27), varying up or down due to terrain, winds, temp, speed and loads.
The furthest I ever drove before the low fuel light came on (supposedly 2.4 gal. remaining) was on the trip where I got 32 mpg - and was either 466 or 468 miles. I'm in bed so aren't going to go out to the car and look it up in the log book to refresh my memory, but it's one or the other. I've never been tempted nor have I needed to see just how much of that supposed 2.4 gallons is usable in varying conditions, given that I drive on roads with steep slopes so much, but I know when the light comes on I've got 30 miles reserve for sure, probably 50 and maybe 60 or even a bit more. Taking all the accumulated knowledge together, I know that unless conditions are extreme my no-worries range is at least 400 miles plus at least a 30 mile reserve, which provides me ample time between stops.
Given current BEVs' shorter range and greater variability due to HVAC use, speed, regen etc., the possible % range variation is wider. BEV range could vary more depending on terrain, but as I'm going to drive like myself not that much from trip to trip on the same or a similar route. unlike in an ICE, heavy, slow traffic including stop and go will affect the range favorably thanks to differences in max. efficiency speed plus regen, and there are some other notable differences, but it's certainly possible to know within reasonably tight parameters what your range will be and what will affect it. Naturally, the more experience you have with a given car the more accurate your knowledge will be.
WetEV said:
GRA said:
WetEV said:
If the variability is greater than the effect, the result might as well be a random number picked up off the street. The key factors to look at on a long trip are weather and speed. Wind, rain and snow can have huge effects on range. Likewise speed. Climate control is mostly a factor is short and/or lower speed trips. Drive an EV enough, you should understand. Experience can teach you, if you let it do so.
limited data: two trips in essentially the same conditions in different cars
Hmm. I commuted to work for years, in all weather, tried all sorts of climate control variations, in the same car, but somehow you learned more in two trips in two different cars. Simply Amazing.
Four trips on this particular route (plus a hundred or so more in ICEs, and my own years of car commuting before I switched to a bike). Naturally, more trips and data gathered in BEVs will improve the accuracy. But please do provide us with some of your data from your experience.
WetEV said:
GRA said:
WetEV said:
"Please don’t dominate the rap, Jack
If you’ve got nothing new to say"
Right back at ya, and when can we expect you to provide some data of your own?
How many people in this forum have taken three trips in an EV? Most don't seem to write as much as you.
Four on this route plus some shorter ones, but certainly not hundreds. But how much I choose to write is up to me, and how much you choose to write is up to you. And its then up to every individual to decide what they read, and how much value to place on it. And now, I'm done with this particular thread until such time as I've done another trip on this route and post the results. I look forward to you posting some data of your own.