4 ms·

Right, but isn’t 92 min / 702 min (11h42m) is a 13% increase, not 23%? (Also, ABRP by default adds 5 minutes “overhead” to charging stops — reasonable for non-s

by zamfi 3y ago

Right, but isn’t 92 min / 702 min (11h42m) is a 13% increase, not 23%? (Also, ABRP by default adds 5 minutes “overhead” to charging stops — reasonable for non-superchargers were you have to futz with everything, but the supercharger overhead is frankly less than a gas station. Pull up, plug in, done.) I found the range penalty for going above 75 mph to be a weird thing…I typically target supercharger arrivals at 15%. If there’s…extra drag, let’s say…I might arrive around 10% or lower. But the battery charges really fast at that SoC, at least on the 250kW superchargers. If the extra drag gets me there 10-15 minutes sooner for a 2-hour segment, I’ll only see a charge penalty of 2-3 minutes. Of course, I’m only thinking about all this stuff because I love spreadsheets more than is reasonable; most people won’t, shouldn’t, and don’t have to bother!

sokoloff 3y ago
The one I typed above for the M3LR the first time was 13h34m vs 11h00m CR-V observed (2-way average). That’s the 23% increase, which I assume ABRP is choosing a time-optimizing cruise speed from the settings panel, so I took its time estimate. (I’m not a Tesla owner, so I’m taking route optimization choices at face value. My LEAF’s range suffers badly at even 70mph.)
- zamfi 3y ago
  Ah, I see. Then I think you may be comparing apples and oranges -- in my experience ABRP is not doing the right thing with charge curves and cruise speed, which is dependent on a large number of unknowable factors at the planning stage anyway (e.g., temperature, wind). The default settings also assume you are traveling at the speed limit, which it sounds like you are not. Roughly, you get about 20% lower range by traveling at 80mph (80mi, 25 kWh, 3.2mi/kWh) vs 60mph (60 mi, 15 kWh, 4mi/kWh), and then lose another 20% going from 80mph to 90mph (90 mi, 35 kWh, 2.6mi/kWh). [0] Peak charging speed is 250kW and is sustained from ~5%-~35%, and then tapers. Charging from 10%-60% is typical, and takes about 13 minutes for about 38 kWh, meaning that each kWh you use adds about 20 seconds of charging. [1] We can integrate these into the speeds and consumptions above to construct effective speeds that account for the charging time required. E.g., at 60 mph you travel 60 miles in an hour, consume 15 kWh of energy, and thus spend 5 minutes charging -- 60 miles over 65 minutes is about 55 mph. nominal -> effective speed (efficiency): 60 mph -> 55 mph (92%) 70 mph -> 62 mph (90%) 80 mph -> 70 mph (88%) 90 mph -> 75 mph (83%) 100 mph -> 80 mph (80%) - whee! So even though you spend more of your travel time charging at higher speeds, your effective travel speed continues to go up well into speeds you're probably not cruising at. In other words, that peak "optimized cruise speed" for a modern EV that can charge 38 kWh in 13 minutes (~175 kW) is well above what you're probably driving anyway. For comparison, if you stop for 5 minutes every 3 hours in your ICE to refuel, at 80 mph you've got an effective speed of 77 mph, about 10% faster than your EV at 80 mph. (The above scenario has you stopping every 1.5h at 80mph in the 75 kWh-capacity EV; of course, you could stop less frequently but with a bit of a hit to your effective speed assuming 0 stop overhead.) Not making any normative claims here about what's better, etc. -- just laying out the numbers as I see them! [0]: https://cleantechnica.com/2018/07/15/tesla-range-plotted-relative-to-speed-temperature-graphs/ https://cleantechnica.com/2018/07/15/tesla-range-plotted-rel... -- model 3 is slightly better than these numbers. [1]: https://cleantechnica.com/2019/06/24/tesla-model-3-on-supercharger-v3-adds-50-range-in-under-12-minutes-charts/ https://cleantechnica.com/2019/06/24/tesla-model-3-on-superc...
  - sokoloff 3y ago
    Thanks! That’s helpful data and rules of thumb. We were moving comfortably with left lane traffic in the Northeast. Speeds varied by state but were still well within the ranges you calculated above.
- _ea1k 3y ago
  ABRP's default assumes really close to the (often incorrectly mapped) speed limits. Having said that, your figures are probably pretty close. You'd just need to adjust the drive time for 80+ instead of ~70, and increase the charge times by maybe 10-15 minutes.

by zamfi 3y ago

sokoloff 3y ago

The one I typed above for the M3LR the first time was 13h34m vs 11h00m CR-V observed (2-way average). That’s the 23% increase, which I assume ABRP is choosing a time-optimizing cruise speed from the settings panel, so I took its time estimate. (I’m not a Tesla owner, so I’m taking route optimization choices at face value. My LEAF’s range suffers badly at even 70mph.)

zamfi 3y ago
Ah, I see. Then I think you may be comparing apples and oranges -- in my experience ABRP is not doing the right thing with charge curves and cruise speed, which is dependent on a large number of unknowable factors at the planning stage anyway (e.g., temperature, wind). The default settings also assume you are traveling at the speed limit, which it sounds like you are not. Roughly, you get about 20% lower range by traveling at 80mph (80mi, 25 kWh, 3.2mi/kWh) vs 60mph (60 mi, 15 kWh, 4mi/kWh), and then lose another 20% going from 80mph to 90mph (90 mi, 35 kWh, 2.6mi/kWh). [0] Peak charging speed is 250kW and is sustained from ~5%-~35%, and then tapers. Charging from 10%-60% is typical, and takes about 13 minutes for about 38 kWh, meaning that each kWh you use adds about 20 seconds of charging. [1] We can integrate these into the speeds and consumptions above to construct effective speeds that account for the charging time required. E.g., at 60 mph you travel 60 miles in an hour, consume 15 kWh of energy, and thus spend 5 minutes charging -- 60 miles over 65 minutes is about 55 mph. nominal -> effective speed (efficiency): 60 mph -> 55 mph (92%) 70 mph -> 62 mph (90%) 80 mph -> 70 mph (88%) 90 mph -> 75 mph (83%) 100 mph -> 80 mph (80%) - whee! So even though you spend more of your travel time charging at higher speeds, your effective travel speed continues to go up well into speeds you're probably not cruising at. In other words, that peak "optimized cruise speed" for a modern EV that can charge 38 kWh in 13 minutes (~175 kW) is well above what you're probably driving anyway. For comparison, if you stop for 5 minutes every 3 hours in your ICE to refuel, at 80 mph you've got an effective speed of 77 mph, about 10% faster than your EV at 80 mph. (The above scenario has you stopping every 1.5h at 80mph in the 75 kWh-capacity EV; of course, you could stop less frequently but with a bit of a hit to your effective speed assuming 0 stop overhead.) Not making any normative claims here about what's better, etc. -- just laying out the numbers as I see them! [0]: https://cleantechnica.com/2018/07/15/tesla-range-plotted-relative-to-speed-temperature-graphs/ https://cleantechnica.com/2018/07/15/tesla-range-plotted-rel... -- model 3 is slightly better than these numbers. [1]: https://cleantechnica.com/2019/06/24/tesla-model-3-on-supercharger-v3-adds-50-range-in-under-12-minutes-charts/ https://cleantechnica.com/2019/06/24/tesla-model-3-on-superc...
- sokoloff 3y ago
  Thanks! That’s helpful data and rules of thumb. We were moving comfortably with left lane traffic in the Northeast. Speeds varied by state but were still well within the ranges you calculated above.
_ea1k 3y ago
ABRP's default assumes really close to the (often incorrectly mapped) speed limits. Having said that, your figures are probably pretty close. You'd just need to adjust the drive time for 80+ instead of ~70, and increase the charge times by maybe 10-15 minutes.