Supercharging letter from Tesla 8-13-2015

[Matteo]

Max* and Johan,

I'm trying to understand how things might look from a user's perspective who does a lot of long distance trips. Can you answer these two questions:

In last 365 days,
1. What percentage of total charging happened at superchargers?
2. What is the maximum number of times you supercharged at the same station?

 

[Max*]

Exit from loop to stop the spamming.

Nice catch! Otherwise we'd see a thread as to "why did I get 7 emails from Tesla!"

- - - Updated - - -

Max* and Johan,

I'm trying to understand how things might look from a user's perspective who does a lot of long distance trips. Can you answer these two questions:

In last 365 days,
1. What percentage of total charging happened at superchargers?
2. What is the maximum number of times you supercharged at the same station?

I've only had my car for 2 months.
1. 60%
2. Erm... I've used my local SpC maybe 4 times? it's kinda far (maybe 15-20 miles), but it's next to a mall, so if I need something in the mall, I'll top off.
O o o and I've used another SpC that's on 2 of my traveled routes probably 4-6 times. But it's about 120 miles from my house.

 

[mknox]

In last 365 days,
1. What percentage of total charging happened at superchargers?
2. What is the maximum number of times you supercharged at the same station?

In my neck of the woods, there is a Supercharger mid way between the city and popular summer cottage/winter ski areas. Lots of people own second homes there. In fact, the Supercharger, I believe, was placed where it is to support travel to/from these areas. If you owned a cottage or chalet and went there on weekends, it is possible you might be at the same Supercharger twice a week, year 'round. Would that be "abuse"? I don't think so, because you would be using the location exactly as intended. But you might get "flagged" for one of these letters.

 

[Matteo]

In my neck of the woods, there is a Supercharger mid way between the city and popular summer cottage/winter ski areas. Lots of people own second homes there. In fact, the Supercharger, I believe, was placed where it is to support travel to/from these areas. If you owned a cottage or chalet and went there on weekends, it is possible you might be at the same Supercharger twice a week, year 'round. Would that be "abuse"? I don't think so, because you would be using the location exactly as intended. But you might get "flagged" for one of these letters.

mknox,

I was thinking about the same thing.

I see my algorithm would include people who do long distance trips all the time. I'm not sure how to exclude them. Assuming somebody is using the Model S only to drive to one location 400 miles away and there is a supercharger 300 miles away from his home, all his trips would be long distance trips. 100% of supercharging would happen at the same station. 100% of all charging would be supercharging. We should exclude this user but I'm not sure how.

 

[Panu]

In previous discussions most people including me seemed to agree that if you always plug in at home you are not an abuser. Those who got the letter: have you not charged at home or have you charged only to 50-60% at home so you can top off at supercharger?

 

[PaulusdB]

Thanks for the clear illustration of the fact that designing the correct 'SuperCharger Abuser Algorithm' is no trivial task.

Even the ground rules for SuperCharger are not explicitly clear (to me).
And given that even the top percentile of owners, investors and dedicated fans of the brand/car (here on TMC) cannot come up with this algorithm, please don't assign this task to the next summer intern.

My suggestion:
if Tesla Motors were to convey the ground rules for SuperCharging, possibly this group effort will lead the world to a solution acceptably close to what Telsa Motors and we deem a 'fair' SuperCharger Abuser Algorithm.

 

[Matteo]

Update: The version below was later superseded by version 3 in message #437.
--------------------------------

OK, I think I have an idea that might work. I picked a user who has a weekend location he visits regularly. At the same time this user is abusing local superchargers near home and near his weekend location. I think the following system would differentiate between long distance trips and local top ups. The idea is to look where the car is parked overnight before and after supercharging. Here is an example that shows a record of 5+ hours parking and supercharging events

8.5 hours parked at home (GPS location A)
Supercharged at station 1
8.5 hours parked at home (GPS location A)
Supercharged at station 1
8.5 hours parked at home (GPS location A)
Supercharged at station 1
8.5 hours parked at weekend location (GPS location B)
Supercharged at station 2
8.5 hours parked at weekend location (GPS location B)
Supercharged at station 2
8.5 hours parked at weekend location (GPS location B)
Supercharged at station 2
8.5 hours parked at home (GPS location A)
Supercharged at station 1

As you see whenever the user drives from home to weekend location, those supercharge sessions would not be flagged because he doesn't park for longer than 5 hours at same location before and after supercharging.

 

[Max*]

mknox,

I was thinking about the same thing.

I see my algorithm would include people who do long distance trips all the time. I'm not sure how to exclude them. Assuming somebody is using the Model S only to drive to one location 400 miles away and there is a supercharger 300 miles away from his home, all his trips would be long distance trips. 100% of supercharging would happen at the same station. 100% of all charging would be supercharging. We should exclude this user but I'm not sure how.

Cough

This is how I see the correct algorithm in Psuedocode, though I likely missed something obvious too...

if(Owner uses superchargers within 100 mile radius of home)
   if(Owner uses superchargers more than home charging) //weeding out the occasional local top offs
      for(1:length(Superchargers used)) // check every SpC he used
         if(SpC stop NOT followed by another Spc stop within 6 hours) //ignore roadtrip cases
            send politely worded letter
         end
      end
   end
end

And then you can easily test the above code through your database, and hand check a few dozen potential recipients to check their usage history to make sure you didn't mess up your algorithm.

It's not rocket science! (har har, SpaceX, har har)

Might need a few extra if-statement for some corner cases. Might be as simple as changing 100m radius to 50mile radius (I don't expect many (any?) person to drive 50miles to a SpC to charge to avoid home charging and then drive back home for 50 miles. you're essentially cutting the car range by 50% doing this). That might weed out most corner cases too.

 

[Johan]

For me, about only 20% is SC but of that 95% is at the same SC which is about 300 km from my home. This is because virtually all road trips I do are to my hometown in Sweden. This is likely pretty common- there's one or two SC where most Supercharging is done. Humans are creatures of habit.

 

[smac]

Thanks for the clear illustration of the fact that designing the correct 'SuperCharger Abuser Algorithm' is no trivial task.

Even the ground rules for SuperCharger are not explicitly clear (to me).
And given that even the top percentile of owners, investors and dedicated fans of the brand/car (here on TMC) cannot come up with this algorithm, please don't assign this task to the next summer intern.

My suggestion:
if Tesla Motors were to convey the ground rules for SuperCharging, possibly this group effort will lead the world to a solution acceptably close to what Telsa Motors and we deem a 'fair' SuperCharger Abuser Algorithm.

Completely agree.

Even if we do come up with a clever algorithm, how on earth do you then communicate this in English (Norwegian/Geman/...) to current owners, and more importantly Legalese for future buyers.

 

[Max*]

Slight tweak.

if(Owner uses superchargers within 50 mile radius of home) //doing a 50mile x2 (100mile) roundtrip to supercharger to avoid paying home fees is reducing your car range by 50% roughly! No sane person would do this.
   if(Owner uses superchargers more than home charging) //weeding out the occasional local top offs
      for(1:length(Superchargers used)) // check every SpC he used
         if(SpC stop NOT followed by another Spc stop within 6 hours) //ignore roadtrip cases
            send politely worded letter
            return;
         end
      end
   end
end

 

[Panu]

For me, about only 20% is SC but of that 95% is at the same SC which is about 300 km from my home. This is because virtually all road trips I do are to my hometown in Sweden. This is likely pretty common- there's one or two SC where most Supercharging is done. Humans are creatures of habit.

Btw. is this SpC close to your destination? The idea might be that you are not allowed to supercharge if you can charge in your destination (which sounds much too strict to me).

 

[Max*]

Thanks for the clear illustration of the fact that designing the correct 'SuperCharger Abuser Algorithm' is no trivial task.

Even the ground rules for SuperCharger are not explicitly clear (to me).
And given that even the top percentile of owners, investors and dedicated fans of the brand/car (here on TMC) cannot come up with this algorithm, please don't assign this task to the next summer intern.

My suggestion:
if Tesla Motors were to convey the ground rules for SuperCharging, possibly this group effort will lead the world to a solution acceptably close to what Telsa Motors and we deem a 'fair' SuperCharger Abuser Algorithm.

There is no evidence that a summer intern did it, lol.

Completely agree.

Even if we do come up with a clever algorithm, how on earth do you then communicate this in English (Norwegian/Geman/...) to current owners, and more importantly Legalese for future buyers.

Why do you need to convey it to anyone? Tesla needs to write the algorithm, implement on their side, and send out letters. Current owners will read the letters addressed to them, for correct reasons, and act appropriately (ignore it? stop abusing the system? etc.).

Superchargers were free for life, no contingencies. You can't change the ground rules for current owners. You can ASK people to not "abuse" the system, sure.

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Btw. is this SpC close to your destination? The idea might be that you are not allowed to supercharge if you can charge in your destination (which sounds much too strict to me).

Not fair either. My MIL only has 120V charging, and only a 100A panel. There is no way I can install a NEMA 14-50 in her garage (for a reasonable cost). I trickle charge in her garage and use the local SpC to top off when we visit.

 

[Matteo]

Max*,

I was having trouble defining home. Therefore I avoided using it in both algorithms. We can not use an address that was declared. That could be wrong or changed. Also a person might live in more than one location. Therefore initially I came up with +20% supercharging and 10+ same station criteria but that would incorrectly flag somebody who has a weekend location. So I came up with GPS location of where the car is parked for 5+ hours before and after supercharging. If you define home according to overnight parking location, then we would end up saying the same thing. I'm not sure what you had in mind to define home. By the way I realized that my second algorithm would fail if somebody is using the Model S for 24 hour tax service with multiple drivers.

 

[Johan]

It's closer to my destination than my home. And I can't rely on destination charging, at least not for shorter trips.

Clarification: I didn't receive any letter. (Did anyone in Europe?)

 

[RobinF]

I wonder how they will word the next letter explaining how they screwed up the determination of who to send the first letter too. And do they send it just to the people who should not have gotten it revealing their ability to develop a better algorithm, or a blanket notice? ... I see a recursion coming on. :redface:

P.S. I did not receive this letter.

 

[techmaven]

I think it should boil down to this...

If I have more than enough charge to get to my destination where I can charge easily in time for my next trip, and I'm taking up a plug at a Supercharger while someone is waiting, I should give up the plug so that they can charge. Since, well, I would want someone to do that for me if I were the one waiting and absolutely needed to charge.

This whole thing should have been phrased as etiquette because we're all in this grand movement together and we need to work together to make this work as smoothly as possible.

 

[Max*]

Max*,

I was having trouble defining home. Therefore I avoided using it in both algorithms. We can not use an address that was declared. That could be wrong or changed. Also a person might live in more than one location. Therefore initially I came up with +20% supercharging and 10+ same station criteria but that would incorrectly flag somebody who has a weekend location. So I came up with GPS location of where the car is parked for 5+ hours. If you define home according to overnight parking location, then we would end up saying the same thing. I'm not sure what you had in mind to define home. By the way I realized that my second algorithm would fail if somebody is using the Model for 24 hour tax service with multiple drivers.

I'll play ball, you're right. I assumed Home was defined and accurate in the nav.

Tesla also has your home address based on your registration (yes, the person may have moved or has multiple homes <-- fringe cases).

The point of the algorithm is to be "good enough", perfect is the enemy of good enough. Using home as either what the nav uses or based on what was registered with Tesla, might have a few false negatives (you didn't send a letter to the person with 2 homes, or you didn't send a letter to the person who moved), but I don't believe it'll have any false positives. And that might be good enough.


If you want to go above good enough, you may start to introduce false positives. How do you define home? What if someone doesn't have a home and lives out of his Tesla? What if you're staying with your inlaws for 6-months? etc. You can adjust the definition of home daily/weekly/etc. but that may lead to more false positives --> what if you're on vacation and the hotel doesn't have a plug?.

 

[Panu]

Clarification: I didn't receive any letter. (Did anyone in Europe?)

OK I thought you received the letter. Probably no one in Europe did.

 

[Matteo]

Slight tweak.

if(Owner uses superchargers within 50 mile radius of home) //doing a 50mile x2 (100mile) roundtrip to supercharger to avoid paying home fees is reducing your car range by 50% roughly! No sane person would do this.
   if(Owner uses superchargers more than home charging) //weeding out the occasional local top offs
      for(1:length(Superchargers used)) // check every SpC he used
         if(SpC stop NOT followed by another Spc stop within 6 hours) //ignore roadtrip cases
            send politely worded letter
            return;
         end
      end
   end
end

Max*,
Your algorithm would fail if somebody has a weekend location. Imagine Home to supercharger is 49 miles. Supercharger to weekend location is 190 miles. The person is using his Model S only to drive from home to weekend location. He has a smart EV for city driving at home and another smart EV for city driving at weekend location.

Home......................Supercharger.........................................................................................Weekend Location