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Hi. I created a calculator for energy consumption between two adjacent superchargers. For now it works only for USA. You select two superchargers, enter speed, temperature and some other details and it shows you energy consumption in kWh, rated range consumption and battery percentage consumption. Elevation is part of the calculation but you don't need to enter that because all elevation data for stations is already there. Also you don't need to enter distance. Also it differentiates between different car models when calculating weight etc. I made this as detailed as I could.
You can find the calculator here: Tesla Model S calculator for energy consumption between two superchargers - Google Sheets
The origin and destination supercharger need to be within the car's range. This doesn't do multi stop trip planning.
How it works:
It is quite complicated. 7 different consumptions are calculated in kWh. These are:
1 of 7: Rolling Resistance Energy Consumption (kWh)
2 of 7: Air Resistance Energy Consumption (kWh)
3 of 7: Additional consumption: Elevation (kWh)
4 of 7: Additional consumption: Climate Control (kWh)
5 of 7: Additional consumption: Tires (kWh)
6 of 7: Additional consumption: 21" wheels (kWh)
7 of 7: Additional consumption: Road surface (kWh)
The two main categories are #1 and #2. I want to give detailed formulas for both of these in case others decide to work on this subject in the future and they might find this useful. ^2 means squared. This is common excel language.
1 of 7: Rolling Resistance Energy Consumption (kWh) = C40*C41*MultiplierData!$R$3*C6*0.44704/1000*C21/C6
C40= Weight of occupants and cargo + pano roof + other hardware + car (kg)
C41= gravity (m/s^2) = 9.81
2 of 7: Air Resistance Energy Consumption (kWh) = C6*0.44704*(C21/C6)/1000*0.5*MultiplierData!$S$3*AVERAGE(C30,C31)*(C6*0.44704)^2)
0.44704 = converts mph to m/s
/1000= converts Wh to kWh
0.5 = This is part of the formula to calculate the force required to overcome drag. The formula is: 1/2 * air density * drag area * speed^2. In this formula the units are (kg/m^2), (m^2), (m/s^2).
MultiplierData!$S$3= Drag area for Model S = 0.576 m^2. Drag area numbers are available on this page: Automobile drag coefficient - Wikipedia, the free encyclopedia Don't multiply drag area by drag coefficient. It is already multiplied. Frontal area * drag coefficient = drag area
C30= Air density at origin (kg/m^2)
You can find the calculator here: Tesla Model S calculator for energy consumption between two superchargers - Google Sheets
The origin and destination supercharger need to be within the car's range. This doesn't do multi stop trip planning.
How it works:
It is quite complicated. 7 different consumptions are calculated in kWh. These are:
1 of 7: Rolling Resistance Energy Consumption (kWh)
2 of 7: Air Resistance Energy Consumption (kWh)
3 of 7: Additional consumption: Elevation (kWh)
4 of 7: Additional consumption: Climate Control (kWh)
5 of 7: Additional consumption: Tires (kWh)
6 of 7: Additional consumption: 21" wheels (kWh)
7 of 7: Additional consumption: Road surface (kWh)
The two main categories are #1 and #2. I want to give detailed formulas for both of these in case others decide to work on this subject in the future and they might find this useful. ^2 means squared. This is common excel language.
1 of 7: Rolling Resistance Energy Consumption (kWh) = C40*C41*MultiplierData!$R$3*C6*0.44704/1000*C21/C6
C40= Weight of occupants and cargo + pano roof + other hardware + car (kg)
C41= gravity (m/s^2) = 9.81
MultiplierData!$R$3 = Road friction coefficient = 0.0165 (I found this by comparing the calculator to actual data)
C6= Speed (mph)
0.44704 = converts mph to m/s
/1000 = converts Wh to kWh
C21/C6 = Duration (h) = Distance (mi) / Speed (mph)
C6= Speed (mph)
0.44704 = converts mph to m/s
/1000 = converts Wh to kWh
C21/C6 = Duration (h) = Distance (mi) / Speed (mph)
C6= Speed (mph)
C21/C6 = Duration (h) = Distance (mi) / Speed (mph)
0.5 = This is part of the formula to calculate the force required to overcome drag. The formula is: 1/2 * air density * drag area * speed^2. In this formula the units are (kg/m^2), (m^2), (m/s^2).
MultiplierData!$S$3= Drag area for Model S = 0.576 m^2. Drag area numbers are available on this page: Automobile drag coefficient - Wikipedia, the free encyclopedia Don't multiply drag area by drag coefficient. It is already multiplied. Frontal area * drag coefficient = drag area
C30= Air density at origin (kg/m^2)
C31= Air density at destination (kg/m^2)
C6= Speed (mph)
0.44704 = converts mph to m/s
Air density calculations are quite complex too. First you calculate Local atmospheric pressure from elevation. Then from Local atmospheric pressure and outside temperature you calculate air density. I can explain these in detail if anybody is interested. I want to add that all this information is available to anybody who wants to use it. Open the spreadsheet, click "File > make a copy". Then you will have your own version to play with. :wink:
You can find the calculator here: Tesla Model S calculator for energy consumption between two superchargers - Google Sheets
0.44704 = converts mph to m/s
Air density calculations are quite complex too. First you calculate Local atmospheric pressure from elevation. Then from Local atmospheric pressure and outside temperature you calculate air density. I can explain these in detail if anybody is interested. I want to add that all this information is available to anybody who wants to use it. Open the spreadsheet, click "File > make a copy". Then you will have your own version to play with. :wink:
The biggest factor that could mess up calculations is headwind. Currently headwind is not part of the calculation. When you open the calculator you will see many columns side by side. The reason for this is because this way you can compare consumption at different speeds or you can compare different Tesla models side by side or multiple people might use the calculator at the same time.
In the file there is a sheet called "Survey". If you drive from one supercharger to another, it would be great if you could fill this section. This would help fine tuning the multipliers. It asks simple questions like what was your rated range when you arrived at this supercharger etc. However I hope it is already fairly accurate. I did test it against some data I found here and there. I hope it is more accurate than EVtripplanner and I welcome any comparisons and comments.
In the file there is a sheet called "Survey". If you drive from one supercharger to another, it would be great if you could fill this section. This would help fine tuning the multipliers. It asks simple questions like what was your rated range when you arrived at this supercharger etc. However I hope it is already fairly accurate. I did test it against some data I found here and there. I hope it is more accurate than EVtripplanner and I welcome any comparisons and comments.
You can find the calculator here: Tesla Model S calculator for energy consumption between two superchargers - Google Sheets
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Thanks for doing this. I just got back from a 5300+ mile trip (DFW to Seattle), and didn't see it till I got back. 253 Wh/mi average.
Aren't these two the same?
1 of 7: Rolling Resistance Energy Consumption (kWh)
5 of 7: Additional consumption: Tires (kWh)
Hi jerry33,
You are right. In the table 1,5,6,7 should all be a single category called Rolling Resistance Consumption (the table is just an example that shows when you select Gilroy, CA to Tejon Ranch, CA superchargers). I didn't merge those because it is easier this way to fine tune the calculator and hopefully it is easier to understand for the reader. But I could move 5,6,7 under 1 and make them sub categories. Then rename "Rolling Resistance Consumption" to "Basic Rolling Resistance Consumption". Then call the total of 1,5,6,7 "Rolling Resistance Consumption". I could do that. I need to think if this would be easier to understand for the reader.
Right now "Rolling resistance consumption" shows what happens if you have 19" wheels and best tires and dry road. Instead if you have 21" wheels, wet road and performance tires, you get small additional penalties for each of these.
| Origin supercharger | Gilroy, CA |
| Destination supercharger | Tejon Ranch, CA |
| Select car | Model S 85 / P85 / P85+ |
| Average speed (mph) | 65 |
| Tires | Performance |
| Wheel size | 21 |
| Weather | Rain |
| Outside Temp (F) | 72 |
| Climate Control On/Off | On |
| Climate Control (F) | 68 |
| Weight of occupants and cargo (lbs) | 300 |
| Pano roof? | yes |
| Energy consumption | 75.02 kWh |
| Range consumption | 262 rated miles |
| Battery consumption | 98.84% |
| Duration | 3 h 29 min 13 sec |
| Distance | 226.7 mi |
| Remaining rated range | 3 rated miles |
| 1 of 7: Rolling Resistance Consumption (kWh) | 38.85 kWh |
| 2 of 7: Air Resistance Consumption (kWh) | 28.76 kWh |
| 3 of 7: Elevation consumption (kWh) | 1.77 kWh |
| 4 of 7: Climate control consumption (kWh) | 0.28 kWh |
| 5 of 7: Tires consumption (kWh) | 0.70 kWh |
| 6 of 7: 21" wheels consumption (kWh) | 1.55 kWh |
| 7 of 7: Road surface consumption (kWh) | 3.11 kWh |
| Total Consumption (kWh) | 75.02 kWh |
Right now "Rolling resistance consumption" shows what happens if you have 19" wheels and best tires and dry road. Instead if you have 21" wheels, wet road and performance tires, you get small additional penalties for each of these.
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OK. I changed it. There are now 4 categories. I made tire, wheel and road surface a sub category of rolling resistance. I also added Wh/mi number. Now it looks like this. If somebody uses this, it would be great if they could fill in the survey page and enter their actual rated range consumption. That would help fine tune the calculator.
| Destination supercharger | Tejon Ranch, CA |
| Select car | Model S 85 / P85 / P85+ |
| Average speed (mph) | 65 |
| Tires | Performance |
| Wheel size | 21 |
| Weather | Rain |
| Outside Temp (F) | 72 |
| Climate Control On/Off | On |
| Climate Control (F) | 68 |
| Weight of occupants and cargo (lbs) | 300 |
| Pano roof? | yes |
| Efficiency | 331 Wh/mi |
| Energy consumption | 75.02 kWh |
| Range consumption | 262 rated miles |
| Battery consumption | 98.84% |
| Duration | 3 h 29 min 13 sec |
| Distance | 226.7 mi |
| Remaining rated range | 3 rated miles |
| 1.1. Basic Rolling Resistance Consumption (kWh) | 38.85 kWh |
| 1.2. Additional tires consumption (kWh) | 0.70 kWh |
| 1.3. Additional 21" wheels consumption (kWh) | 1.55 kWh |
| 1.4. Additional road surface consumption (kWh) | 3.11 kWh |
| 1 of 7: Total Rolling Resistance Consumption (kWh) | 44.21 kWh |
| 2 of 7: Air Resistance Consumption (kWh) | 28.76 kWh |
| 3 of 7: Elevation consumption (kWh) | 1.77 kWh |
| 4 of 7: Climate control consumption (kWh) | 0.28 kWh |
| Total Consumption (kWh) | 75.02 kWh |
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Some real world numbers:
Started rated range 211 miles.
Temp around 70s, dry, no wind, minimal elevation changes, drove with TACC around 65-70 (varied due to traffic). Minimal HVAC use.
Picture one was first leg of the trip with 32 miles on the trip and 179 miles left (211 miles total).
Picture two was the entire trip with 65.3 miles on the trip and 146 miles left (211.3 miles total).
Maybe that HVAC is special!?:wink:
Started rated range 211 miles.
Temp around 70s, dry, no wind, minimal elevation changes, drove with TACC around 65-70 (varied due to traffic). Minimal HVAC use.
Picture one was first leg of the trip with 32 miles on the trip and 179 miles left (211 miles total).
Picture two was the entire trip with 65.3 miles on the trip and 146 miles left (211.3 miles total).
Maybe that HVAC is special!?:wink:
FlatSix911
Porsche 918 Hybrid
Why do the Tesla graphs show rolling resistance as a small linear growth value, vs drag being the largest and exponential growth, and your calculations have rolling resistance as the highest consumption?
i.e. http://c1cleantechnicacom.wpengine.netdna-cdn.com/files/2016/02/Whpermilevsspeed.jpg
Great post overall! We are planning a roadtrip in our Model X this summer that will include a lot of elevation change and are trying to recreate your percent of rated number calculations for this factor. Based on your description, we've com up with the formula:
[((elevation gain'/1000')*10mi)-((elevation loss'/1000')*6mi)]/actual trip distance (i.e. map distance)
However, the % results aren't corresponding to yours. What are we doing wrong?
Hi,
Most of my numbers are in % for the whole trip, but the elevation change numbers are absolute numbers that only apply to the hill in question. So rather than dividing by the trip distance and applying it as a percentage, you just add the number of miles "spend" on the mountain from the total.
So for a 135 mile trip at adding 12% for speed and 8% for wet roads and going over a 3,000' pass, you'd get numbers like:
135 * (100% + 12% + 8%) = 162, how much rated range you'd need if it was flat
162 + ((3 * 10) - (3 * 6)) = 174 miles of rated range required including going over the pass
Note that I wrote this post long before the trip calculator was in the car. It can't include everything (it doesn't know what headwinds are, for example) but it does include elevation changes, although it seems to underestimate energy used going up and underestimate energy re-gained coming down, so things might not look good as you approach the top of a hill but will improve back to where you expect them as you come down.
Most of my numbers are in % for the whole trip, but the elevation change numbers are absolute numbers that only apply to the hill in question. So rather than dividing by the trip distance and applying it as a percentage, you just add the number of miles "spend" on the mountain from the total.
So for a 135 mile trip at adding 12% for speed and 8% for wet roads and going over a 3,000' pass, you'd get numbers like:
135 * (100% + 12% + 8%) = 162, how much rated range you'd need if it was flat
162 + ((3 * 10) - (3 * 6)) = 174 miles of rated range required including going over the pass
Note that I wrote this post long before the trip calculator was in the car. It can't include everything (it doesn't know what headwinds are, for example) but it does include elevation changes, although it seems to underestimate energy used going up and underestimate energy re-gained coming down, so things might not look good as you approach the top of a hill but will improve back to where you expect them as you come down.
FlatSix911
Porsche 918 Hybrid
MDMGSO47
Member
I understand there are a number of factors that affect range. For those of us who are less mathematically inclined (or who are too lazy to do the math), what's a rough guess of the percentage of the range numbers predicted by Tesla that are achievable in the real world assuming normal freeway driving at moderate temperatures? 70%? 80%? 90%
FlatSix911
Porsche 918 Hybrid
Here is the range impact of the 22" wheels for the Model X on the Tesla configurator.... 10% - 15% equals 25 - 37.5 miles of range lost.
FlatSix911
Porsche 918 Hybrid
I would suspect that the majority of the range decrease is due to increased mass of the 22 wheels ... approximately 40 lbs
Numbers predicted by Tesla - you mean, the range-estimation tool on their website? (Probably, because that is what you are replying to). I haven't played with it for quite a while, but when I did the tool (outside of its limited parameters and things it left out) seemed to match real-life miles very well when conditions were good. Headwinds, elevation etc. were not counted; but if I didn't hit any, I got pretty much 100% of what they estimated. (In very poor weather I have gotten as little as 2/3 of what it predicts, though that is not common).
If you happen to mean the EPA numbers, those are a mixed-test number that aren't supposed to exactly match highway miles at any particular speed. But if I drive ~65 around here on a warm, windless day on flat road...yeah, I pretty much hit 100% then too.
You could also mean the trip tool in the car. That has some good points, like it's in the most useful place, it considers elevation, etc. But it's still the one I trust the least in some respects (it is still a very valuable tool; especially given its real-time status of how you are doing; you just have to leave a buffer). In addition to still not accounting for headwinds, and if it accounts for temperature I don't think it's too good (unless it's lost in one of the other problems), it also seems to do elevation wrong - I consistently under-perform its estimate going uphill, but overperform going downhill. That said, even if it's not the most accurate, I have sometimes overperformed its predictions in all sorts of weather. However, I have more often underperformed. Usually not by a whole lot though, unless I'm speeding and expect to.
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Agree with ChadS. Mine easily get more than 100% than EPA number at speeds 65mph with flat road no headwind no heaters.
MDMGSO47
Member
I live in Greensboro, North Carolina, where the weather is moderate for 8 months of the year. We have ordered a S70 to be delivered late May. My long distance travel in the Tesla will normally be about 180 miles one way (Asheville) or 200 miles round trip (Charlotte). The 200 mile one way trip has an elevation climb or drop (depending on the direction of travel) of 1,200 feet. We will be doing interstate driving with the heat or AC on depending on the weather.
The Tesla site says we can expect a range of 215 miles at 70 mph at 70 degrees (down to 195 at 32 degrees) with the AC or heat on. Are those estimates acheivable under normal circumstances? The margin is pretty small on both trips. In addition, there are no Superchargers and very few other type chargers in the 180 miles between Greensboro and Asheville. Is it reasonable to believe we will actually get a 200 mile range on the interstate?
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3 of those factors are out of your control.
evtripplanner.com would tell you minus startup costs (i.e. cold/heat soak), if it wasn't down.
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