NewsCoulomb
Member
- Joined
- Jun 24, 2021
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- 0
- Messages
- 21
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- 5
- Location
- California
- Vehicles
- Bolt EV, Ranger Electric
Thank you for illustrating my point. If ABRP was a teaching tool, it would not require years of experience in "optimization and estimation" and a lengthy explanation in order to use effectively, would it? And again, that is one of my key issues. It's set up to be easy to use as though their data is accurate and up to date. For some EVs and charging networks, it appears to be. For others, not so much.I do understand. You think ABRP's model is incorrect and that, therefore, the program can't be used.
The fact that you even expect it to be "accurate" means that you aren't quite up to speed on how it works. You cannot expect it to be accurate. If the model is good it will produce a plan representative of what might be expected under nominal conditions.
Again your saying that conditions exactly match the base line is, forgive me, naive, because they can never do so. Do you drive at constant speed? Is that the speed you put into ABRP? Is it dead calm throughout the entire trip?
This says you are really missing the concept so let's see if maybe a bit of examination of an ABRP session will help you grasp it. Before I launch into that I will point out that I do have a fair amount of experience with optimization and estimation and I find it useful as do thousands of others so either you are missing something or the rest of us are wrong.
Let's get this out of the way first as it probably a good place to start. The reason the final SoC is 10% is because YOU told the program you want to arrive at the destination. It will, therefore, optimize over the route parameters in order to get you there as fast as possible subject to the constraint that you arrive with 10%. As I gather the route between these two places is Veterans/Steens highway or back roads it clearly has to pick that highway for best time. What does that allow it to adjust? The charge time at Winemucca. It will tell you to charge for as short a period as you can and still be pretty sure (its an estimate) of 10% charge at the destination.
So I loaded this route into ABRP but used Rivian parameters rather than Bolt. The Bolt model is probably better than the Rivian model because there are real cars out there. ABRPs model represents guesses. It tells me that I will drive 2:18 to arrive at Winemucca with 39%, charge there for 13 minutes to 65%m drive another 3:24 to the destination arriving with 10% left in my battery. Some assumptions went into this:
a)400 Wh/mi consumption at 65 mph
b)Leave with 85% SoC on the battery
c)Drive at the speed limit
d)No wind.
e)I want to get there as quickly as possible under these constraints.
Now it is true that if someone in Reno says "Hey, I want you to take the R1T up to Burns tomorrow" and I say "How far is that" and he says about 400 miles I know immediately that I'm going to use about .4*400 =160 kWh and that with a 170 kWh battery I am going to need to charge once on the way. But when I put the trip into ABRP I know that I will be using a bit more than 400 Wh/mi because of terrain and or speeds above 65 mph and that, given the speed limits, it will take me about 5:44 of driving and 13 min of charging and that Winemucca is a good place to charge because it has big chargers. I also see right away that I have a choice of Roberto's only 801 ft. from the chargers, Dos Amigos 1127 feet away and 4 other choices. I also see right away that if I am feeling lucky and have a couple of hours to kill I can run up to the Say When Bar and Casino for a bit while I charge at the 40 kW station there.
I now know lots more about the road from Reno to Burns than I did 10 minutes ago. And I am guessing that all this information is accurate.
Now as for learning something about my vehicle and the trip let's play some games. If I have to charge 13 minutes leaving it with 85% on board could I not save some time if I left with 95%? Indeed I could. If I enter that into ABRP then I'd only have to charge 11 minutes. Suppose I decide to take advantage of that by driving faster say 110% of the speed limit then I'll use more energy (471 Wh/mi) and I'll have to charge 15 minutes but I'll be 5:15 on the road for a total of 5:30 for the trip as opposed to 5:51 at the slower speed and departure at 95%.
I've now got a pretty good picture of what the morrow will bring. Will I arrive at Winemucca after 2:18 with 39% on the battery? Very probably not. A head or tail wind will probably get me there earlier or later and the consumption will be more or less than 400 Wh/mi. But the number is going to be close to 39%. Will I leave with 65%? No, probably not. I'll dawdle over my MicyD's and/or decide to put in 70 or 75% for some margin at the destination. Will I arrive at the destination with 10% SoC? No, it will be more than that. Has ABRP been a big help to me in planning this trip? Yes. Could someone using ABRP learn something from an exercise like this one? We hope so.
Obviously, no trip is going to perfectly match ABRP's baseline numbers for typical driving (that would be impossible); however, if the conditions are reasonably similar, then one can expect the real-world results to be reasonably similar. But they aren't. Sure, maybe I stated that I wanted to arrive at ~10%, but how (exactly) do I leave Reno with 100% and somehow magically use exactly 90% to arrive at the specific charger I need when the next nearest charger is 50 miles away? Did I just magically plug in a route where the first leg required exactly 90%? Something's wrong with ABRP's calculation.
I can tell from experience with the 2020 Bolt EV that, under typical driving (what should be ABRP's baseline), I would arrive at Winnemucca with ~25% (approximately 15% more than ABRP's projection). That's too large of a margin of error for a tool that is supposed to be providing estimates on typical conditions and driving.
As for what's specifically wrong with that picture, I'd say pretty much everything. If I were "planning" that route for myself, first, I'd complain because nobody has chargers in Susanville or Alturas (Highway 395 is my preferred route as I'd typically be coming from west of Reno). Then I'd open PlugShare. Based on what I saw, I'd plan a trip in a 2020 Chevrolet Bolt EV accordingly:So over to you. What's wrong with the picture below?
- Leave Reno with a full battery.
- Arrive at Winnemucca Electrify America with 20% to 30% battery (possibly having to adjust along the way for conditions). That's what can be expected at baseline, freeway efficiency in average conditions.
- I'd charge up as long as the stop made sense. There's not much to do at that location (nor are there places I'd like to eat), so other than walking over to LUCID Cannabis and being disappointed it wasn't an EV showroom, I probably wouldn't want to spend more than 30 minutes charging.
- As a result, I'd expect to leave with between 60% and 70% battery, which is not enough to make the remaining 222 miles at posted speeds.
- I refuse to drive less than the posted speed unless it's an emergency or weather dictates, so I'd jam it up Highway 95 at 70+ mph, leaving me 70 miles short of making it to Burns.
- After about an hour, I'd stop a Quinn River Market in McDermitt, NV (with what I'd estimate to be about 30% battery) and charge up on one of the two Greenlots 50 kW BTC Power Slim units that ABRP never even presented to me as an option when attempting to use it to plan the route.
- I'd probably charge just a little bit extra in case, and after 30 to 40 minutes, I'd expect to leave with close to 80%.
- I'd drive the speed limit to Burns and arrive with 10% to 15% battery.
So again, bringing it back to Rivian... The only thing that would change with this route plan is that I'd have an additional option for charging at a RAN station in Winnemucca. I don't know what amenities would be nearby, so I don't know how long I'd want to charge there. I also haven't seen data on how long the 180 kWh R1T takes to charge to full, but 80% still might not be enough for me to comfortably drive 220 miles at 70+ mph. Because RAN doesn't appear to have plans for Highway 95 north of Winnemucca, I'd hope that (unlike ABRP) Rivian includes those Greenlots chargers on their navigation and route planning.
And again, I can now illustrate my other issue with ABRP. I'd be new to the R1T (not experienced like I am with the Bolt EV), so I'd be relying on ABRP's baseline numbers to be somewhat accurate. A 15% margin of error could easily leave me stranded in the desert, and caveat emptor or "you should have slowed down" on one of the fastest driven highways in the country won't cut it.
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