Solution to Supercharger sharing problem

Solution to Supercharger sharing problem

The issue of sharing Superchargers has been raised here before along with a number of ideas to contact (or penalize) owners who leave their fully charged cars plugged in while others wait for a spot to open. Personally, I don't mind being contacted and moving my car if it is sufficiently charged and someone else needs a charge to get to their destination. However, I'm not fond of the idea of leaving my cell phone number on my $100K car for the world to see. While the solution I came up with isn't perfect, it does facilitate this communication while maintaining an owner's anonymity. For one thing, owners have to have the smartphone app for this to work. For argument's sake, let's assume most Model S owners use the app and opt-in to use this proposed feature.

Let's say you pull up to a Supercharging station and all the spots are occupied. You launch the app which uses your phone's GPS to determine that you are at a Supercharging station. Through it's connection to Tesla's servers, it also knows that all the operational Superchargers are occupied as well as the owners of the cars plugged into each station. Meeting these two criteria would enable a new option in the app: the ability to send a message to the owner(s) of car(s) that are fully charged, asking them to move so you can charge. If no cars are fully charged, you can send a message to all owners currently charging and ask if they are charged enough to get to their destination and wouldn't mind moving. These messages can come either as a notification in the app or as a text message. Since Tesla has all our info, we should be able to have a dialog with other owners without knowing any of their contact info. In addition, since Tesla also knows the status of the Superchargers and our cars, we can communicate with other owners without knowing the state of charge of their cars or in which spot they're parked. Let's say for one reason or another, I don't acknowledge a message asking me to move my fully charged car. No one would know that my black Model S on the end is the one that's fully charged, further preserving my anonymity.

Note that this can also work at public HPWC stations like those at malls with a Tesla Store. While Tesla may not know the status of a HPWC, the app can determine the owner of the car in your proximity that's plugged into a HPWC.

cfOH | July 4, 2013

Not a bad idea!

As an extension, if there are cars waiting, Tesla's servers could manage a virtual queue for spots at any given SC station. For that matter, the mobile app (or in-car touchscreen app) could direct you to alternative charging locations if the SC is full.

Lots of opportunities to make this a VERY "smart" service.

ir | July 4, 2013

" which uses your phone's GPS to determine that you are at a Supercharging station."

For security reasons, Tesla should use the GPS inside the car to know if you are at the supercharger. Otherwise, I could bring my phone, leaving the Model S at home and pester the folks using the Super Charger.

mcx-sea | July 4, 2013

What if person charging, or waiting to charge, does not use a cell phone?

Brian H | July 4, 2013

The onus is on such a person to stick close while charging, and basically must take what comes as far as getting a slot.

Jolinar | July 4, 2013

very nice idea, you should contact Tesla with it.

well, nothing happens, it wouldn't be mandatory.

wheatcraft | July 4, 2013

A very good idea. The only problem is that once the owner walks away from the car, and some time passes, the touchscreen turns off, and the charging LED around the chargeport shut off. So there is really no way for someone who just walks up and looks at the car to know if it is fully charged.

Even so, it is still a good idea, one could just send a friendly reminder that there is a queue, and please be sure to move your car when it is fully charged.

tes-s | July 4, 2013

I like your approach - providing information to help people make informed - and hopefully considerate - decisions. Certainly a good place to start.

Perhaps teh app could rate your SC "etiquette" - provide the owner with a score that shows how considerate they are when others are waiting.

Sudre_ | July 4, 2013

I don't think all that is even needed. The car should signal the owner's app when it is done charging at a supercharger, simple.
From there it would not be hard for the server to see 10 Model S's parked around 6 chargers and add a message that others are waiting in line. No need for the anyone to do anything extra.

A person could easily opt out by turning off the app access in the car that way they can hog the SC all day and not feel guilty.... which a few will do anyway.

Right now tho, the app doesn't run in the background. I typically exit the app anyway after looking at it because it won't load next time if I don't... so in that respect we are still rather far away from this simple add.

tes-s | July 4, 2013

App simply needs push notifications.

Manta | July 4, 2013

@ir - Good point, but since the app also knows where your car is, it would know if you're at a Supercharging station and your car is at home.

@wheatcraft - Tesla knows the status of all their Superchargers, so they know if a station is plugged into a car and charging at full rate, slower rate (almost charged), or not charging at all (fully charged). As a result, Tesla could direct the request to the appropriate owner without the requestor knowing the state of charge of any of the cars.

Manta | July 4, 2013

@Jolinar - Earlier on I had heard that Tesla staff read these forums. (Does anyone know if they still do?)

@tes-s - Thanks. That's exactly what I was trying to accomplish.

@Sudre - To track the cars in proximity to a Supercharging station would require a lot of computing power compared to my original proposal and assumes (although probably true) that a Model S owner is in the area to charge and not just grab a bite. It's also true that someone could opt out and park at a Supercharger all day. I'm going on the assumption that most owners would do the courteous thing if they knew someone else needed a charge. Lastly, (and I don't know about Android) iOS devices can receive push notifications without the app running (assuming the app had push notifications). Communication could also be initiated in the app and then continued using SMS via Tesla servers since they have our contact info.

David Trushin | July 4, 2013

Chargepoint sends me a text when charging is complete or stops for any reason.

Mark K | July 4, 2013

A worthy idea that should get attention by TM. (Also posted about this elsewhere).

TM's incentive to do this is that anything that increases the efficacy of the SC network supports their mission.

There is already plenty of data and computing power on TM servers to handle this.

Remember that TM knows the current state and location of all the cars and the SC's, even without the smartphone app. (The cars have their own GPS computers, and the SC's are networked to TM servers).

There are many detailed features that can be discussed, but the fundamental objective here is efficient queue management.

You don't need the app to get notices, because TM has your contact info at their server. They can text you.

But having the app can add to the utility. You can see the queue size and estimated wait time while you're away from your car.

After they get some basic functionality for people already at SC's, they can then add functions to the car nav SW to manage requests for charge slots from people in the vicinity.

This will be an evolving area with rich opportunity to make things simpler and more efficient for Model S drivers.

TM so has an opportunity to really do this right, so as to set the motif for other automakers who either join in or emulate TM's network.

Brian H | July 4, 2013

A few too many "IIF-THEN" loops, I think. TM will stick with the KISS route of adding units.

memcd | July 4, 2013

Let's not make it so complicated: If you leave your car leave your cell phone number on the dash.

AmpedRealtor | July 4, 2013

This is simple. Notify the owner when the desired charge is reached. Owner gets 20 minutes to move the vehicle. If not, owner gets a warning the first time this occurs. If it happens again, owner's vehicle is banned from all Tesla Stations for a period of 30 days. Three strikes and owner is banned from Tesla Stations for 12 months. This includes battery swapping.

Using a Tesla Station is a privilege. Abuse that privilege and you should lose it.

negarholger | July 4, 2013

I have a question. What super charger besides Gilroy has these type of problems reported?

We know Gilroy is a problem. Just checked it out on our way back... very light traffic on the 101 and seven MS at Gilroy at 4 pm... I would have been number 8 if I needed to charge.

Mark K | July 4, 2013

One very simple thing that would help is to show the number of available bays at each SC on your nav screen.

That would save you unnecessary stops.

Brian H | July 4, 2013

Enforced by whom? TM sure as daisys don't grow in Hades will not.

ir | July 5, 2013

"Good point, but since the app also knows where your car is, it would know if you're at a Supercharging station and your car is at home."

@paul_villasenor: the phone knows where the car is because Tesla HQ was using the car's built-in GPS to know where it is. Just cut out the middle-man (eg. your phone & it's GPS) from the process by having Tesla trust the car's GPS signal directly. Besides, location from your phone can be spoofed (proof is the fact that somebody on the forum has already reverse-engineered the network protocol between the phone & Tesla HQ). The signal from the car is much harder to spoof because Tesla owns both ends of the link and can secure it better.

Manta | July 5, 2013

Just cut out the middle-man (eg. your phone & it's GPS) from the process by having Tesla trust the car's GPS signal directly. Besides, location from your phone can be spoofed...

Would anyone really go to that much trouble just to "pester the folks using the Super Charger"?

mrspaghetti | July 5, 2013

Sudre_ +1 - keep it simple

@ mcx-sea - how many people who drive a Tesla do you think there are who do not use a smart phone? I'd bet money the number is extremely close to zero.

fuellss | July 5, 2013

@Kleist-We needed to charge at Gilroy yesterday to make it home to Sacramento (from Monterey). We waited about an hour for a spot. In the mean time owners did come out to put their bags in the trunk and then returned to shopping. We assumed they were down to 0 and needed a full charge. We only charged enough to make it back home. There was a owner waiting to charge when we left. A little sticker on the SC that says "Please unplug after desired charge (mileage)" may be helpful. It did seem like the same cars were still charging as we were leaving. I could be wrong. Its hard to believe owners would stay plugged in after they got their needed charge. Waiting was fine, we were in no hurry to get home to 107 temperature..

Sudre_ | July 5, 2013

Can't wait for the day when my Google Model S will unplug itself and pic me up at the front door.... or park in an adjacent spot and let me know it;s ready to go.

negarholger | July 5, 2013

@Calover - Gilroy to escape the Sacramento heat? For me Gilroy is hot as hell in the summer. Monterey / Carmel is always an easy escape when it is hot in the valley. Usually I don't need to charge in Gilroy, but always check it out. Charge rates in my experience are very inconsistent in Gilroy even with a low battery I have seen everything between 50 m/h and 290 m/h. Hopefully TM can expand Gilroy soon.

fuellss | July 5, 2013

@Kleist-We went to Monterey to escape the Sac heat. We were in Gilroy late afternoon to charge to get home. Gilroy was breezy and cool in the shade. If charge rates are inconsistent in Gilroy, that may explain why the same cars needed to charge so long...We were in/out of the charger in 30 minutes..

skulleyb | July 5, 2013

You stay anonymous and the rest of us in the mean time will hopefully be courteous enough just to leave a phone number, Im sure 99.9 percent of the time no one would have an issue.
But for those of you who worry about their precious privacy then by all means just keep track of your charge time.

skulleyb | July 5, 2013

I do like the the OP's idea for the Tesla app in the future.

cfOH | July 5, 2013

If you're within 50' (per GPS) of a Tesla station, the app should let you push a message out to the owners of all cars currently parked at that station asking them how long they'll be. That would preserve anonymity while permitting enough communication to relieve anxiety.

Punitive measures can wait until it becomes a real problem, if even then. When busy stations offer both SC and pack swaps, I expect there won't be much arguing.

hsadler | July 5, 2013

Problems today at the Gilroy SC.
When we got there, it was full, and 2 cars waiting. A few minutes later one car had finished so one started which left one ahead of us.

While we waited another showed up - now three in the queue. Ten minutes and we were up as another arrived and joined the queue. We were just charging enough to get us home plus a buffer in case of problems - so we didn't expect to be that long - went to grab a sandwich at Erik's while we monitored the charge via iPhone.

Unfortunately we were at a slow charge rate, so we knew it would take a little longer. There was a blue MS in the shared stall and we figured when they were done - our charge rate would increase. Thirty minutes go by, and then our charge rate increased, so we waited another 15 min before heading back.

When we got back, blue was still in their stall - we knew they weren't charging because our rate had gone to Max. But there were 5 cars in the queue. The blue people were with their car the whole time - so they knew others were waiting.

It's just that I see this as becoming a major problem if a solution is not introduced. Yes, it was a holiday weekend, but this was in the middle. The beginning and end of holiday weekends will definitely be busier.

Blue had HOV stickers, so they were not new owners.

Bighorn | July 5, 2013

During the shareholder meeting, Elon acknowledged problems at Gilroy and suggested it be avoided--easier said than done, I imagine.

mdemetri | July 5, 2013


Just because your Amps zoomed up does not mean that the blue was finished a 'range charge'. As you approach max charge, the amps go very low (I may be wrong but I think I saw as little as 5 amps near the end of a range charge at Gilroy the other day) and therefore the Amps on the shared car will go up dramatically as max range is approached on the other car. Think about it, why would the blue sit in their car knowing others were waiting. Much more likely is that they were waiting for the last few miles of a range charge.

IMO, the vast vast majority of the problem is not from people shopping or occupying a space when they have completed their charge: it is the slowness of a max charge. For many, the extra few miles of a range charge are essential for their trip (for example, we were going to Yosemite from Gilroy and every last mile was essential).

Thus, I think the only practical solution is more and faster SC. IMO this all that is needed solve the problem. I note the new SC's on the 101 have 8 stalls, as does Tejon pass. My experience at Tejon has been much much faster charging and lots of stalls available.

akikiki | July 5, 2013

Using Google Voice a person can register their cell phone number and get a new area+number to use exclusively for use at charging stations where they would ordinarily be reluctant to leave their real phone number. Using this method a owner could mask their real cell phone number but still make a number available for calling when their car is charged. The Google Voice service doesn't cost any $$$ either.

stimeygee | July 5, 2013

Just have the app send a text when its done charging !

Brian H | July 5, 2013

Elon said the new SCs (or modified SCs) would delay the drop in charging rate longer (till a higher % charge), thus cutting down total time.

mrose17 | July 5, 2013

stimeygee - i agree. i think it would be a great idea to have a push notification to the app when charging completes at a supercharger. that deals with inadvertent absenteeism.

until then, although i haven't received delivery yet, i've already had a nice laminated card printed up listing my google voice number along with some polite text apologizing for loosing track of time.

i suspect that any other counter-measures would be counter-productive...

hsadler | July 6, 2013


If that were the case, I stand corrected. But the charge indicator was not glowing and they were close enough ( doors open - in and by the car.)

But maybe there were problems with the charger which caused this. Anyway, hour and half (at least) is not good. Hope Tesla figures out a solution. Gilroy made need more than 8 planned chargers. Very close to a large city on the only real path between CA's largest cities. If you use I 5 or 101, almost all will pass thru Gilroy.

djm12 | July 6, 2013

If you look at the Supercharger map, you'll see that three new Supercharger locations are slated within the area around Gilroy by the end of the year. This may take some pressure off of that location eventually; however, it may just build back up as more Tesla's roll of the line.

The numbers; however, lead to an interesting problem. California probably has around 4,000 Tesla's on the road today. By the end of the year, there may be a total of 6,000 and by the end of next year, 10,000-12,000. Yes, there are more SC locations planned, but many of these are along less traveled routes, like the 395 in the east, the 5 in the north and the 10 in the south. (hmm...none for the 99) I think it's fairly obvious that Tesla will need more SC locations and more SC stalls at each location than they have planned.

It's not reasonable to expect no lines even during the most highly congested times, like the 4th of July weekend. However, we do expect that wait times will be reasonable and that folks will not disappear for an hour to go shopping while other people are waiting.