Thats awesome. Mind if I borrow?
Also how does temp factor into your equations? Do you assume a threshold for using heat?
Borrow at will. If you make some improvements, share back!
My use of the temperature is a very rough approximation that fits Chad Schwitters' in the field observations/data.
I didn't include heat or A/C in the cabin... i could, but the margin of error for speed fluctuations makes adjusting for heat nearly negligible. Probably because I use range mode for heating and cooling 100% of my time.
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Hey Andy,
Thanks for posting this. There are two changes that I think would be awesome 1) the supercharger charging rate could change for different charge levels and 2) the supercharger time could factor in charging 'enough to get you to the next stop +/- some constant. I thought that's what you were going for with 'Needed +margin' but it doesn't behave that way.
I actually have never hit the supercharging rate in my spreadsheet.
I have a way to go to calculate that rate, as it varies greatly by battery level. I know I could work out a function, but just haven't taken the time to make one to roughly approximate yet.
The way the sheet works is that it will suggest enough rated miles + 20 (the 20 is adjustable) to make it to the next waypoint. The time is based on the charging rate per mile to make the range.
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This is excellent. Can we make adjustments for 21" vs 19" wheels? If so, what would those be? This opened my eyes. I thought a trip from my house in stockbridge, ga to Tesla in Tampa would only be 6hrs or so of driving and 6hrs or so of charging... all do-able if we got up early enough on Saturday morning to make it to Tesla before they close at 4pm... but your spreadsheet is telling me 16.5hrs with two stops on 14-50's. It's critical that we make it to Tesla before they close so I can leave the car with them for safe keeping and to do some service while we're on a week long vacation cruise... Reality is now setting in that that's going to be too grueling to do in one day.... especially if these numbers are based on 19" wheels.. There's a DC charger at the Nissan dealership in Ocala, but good luck finding someone to let you "borrow or rent" their CHAdeMO adapter. :crying:
The distances are using 21" turbine wheels. You might get 5 to 5% more miles, depending on your speed and headwind.
But, that's a long trip for 14-50 charging. You will spend 10 hours charging for 6.5 hours of driving your Model S. Assuming your stops are the KOA near Ashburn, GA and the Hampton Inn in Gainesville, FL (but watch out for Gators.
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I have a similar spreadsheet for my trips but as I never get ideal energy consumption (160Wh/km) I add a variable which is my expected Wh/km based on the driving style and average speed (if I am on my own and in no rush I can go slow, but if I am with the family or doing a trip to be written about in the press I try to go at normal speeds).
Then I also factor in climbs (-5km/100m) and drops (+3km/100m).
I haven't found climate to be all that decisive in so much as I use maybe 5kms of ideal reange for every hour the heating is on for an ambient temp of about 5C. That said, it is something I will try to add in.
Drving style is the biggest influence for me.... If I go at an average of 90km/h I can get an energy use of about 185Wh/km whereas at 110km/h its more like 220Wh/km. These give correction factors of 160/185 (=0.86) and 160/220 (=0.72) to the ideal range.
One other thing I like to include is a little dead time at each charge stop as it always takes 5mins or so to find where the charge point is and plug in.
And the final factor that I have yet to add but that I think really impacts range and energy use is the prevailing wind!! A 10km/h head wind can really imapct energy use.
Have you verified your estimated arrival times and remaining range etc. with the actual readings? I am getting quite accurate now after a few big trips.
Thanks for the review!
I'd love to add the factors for headwind, and elevation, like the Green Race web site does. A larger project. But I hear Tesla is working on that (thanks, Elon!)
Good idea adding in the "dead time".
I did a real-world verification on my trip from Portland, OR to San Jose CA for TESLIVE this summer. It was very close to accurate, but I didn't have a means to measure headwind, which is why it was off a bit. And we ended up not staying an extra hour on an HPC which wore away my +20 margin for one leg, had to make an in-between 14-50 stop. Otherwise, the plan was pretty much right on.
