Suggestion for Tesla: how to maximize Supercharger power output between paired stalls

[David99]

A little OT... Tesla could change the sharing method on normal Superchargers to be 50/50 when two cars are plugged in giving each 72 kW. If one car draws less or no other car is on the shared stall, it would give 100% power to the car plugged in. This way you would get full power when available but never drop below 72 even when busy.

 

[Cosmacelf]

A little OT... Tesla could change the sharing method on normal Superchargers to be 50/50 when two cars are plugged in giving each 72 kW. If one car draws less or no other car is on the shared stall, it would give 100% power to the car plugged in. This way you would get full power when available but never drop below 72 even when busy.

That’s genius!

 

[Captrod]

Wouldn't half of 120kW be 60kW, so that on an equal sharing situation, whether you were first or second to be sharing, each would get 60kW? If the first person were getting 120kW, then his rate would drop in half upon the arrival of car #2. That wouldn't make me very happy!

 

[MP3Mike]

Wouldn't half of 120kW be 60kW, so that on an equal sharing situation, whether you were first or second to be sharing, each would get 60kW? If the first person were getting 120kW, then his rate would drop in half upon the arrival of car #2. That wouldn't make me very happy!

The Supercahrgers are capable of 144kW, but currently cars top out at ~120kW. So splitting capacity in half would be 72kW per car.

 

[Captrod]

The Supercahrgers are capable of 144kW, but currently cars top out at ~120kW. So splitting capacity in half would be 72kW per car.

Well, I guess I'm still capable of learning something new every day! I thought the charger capacity was 120kW; In the case of the charger capacity being 144kW, as you state, David99's solution sounds pretty good to me too, MP3Mike! Are you listening, Elon?

 

[PLUS EV]

But then you'd have to worry about some moron plugging into your paired stall at an otherwise empty supercharger. Anyways this is way off-topic.

 

[David99]

But then you'd have to worry about some moron plugging into your paired stall at an otherwise empty supercharger.

Yes that's the downside. Question is, what is fair. Is it fair to have the person who came first get as much as possible and the other one gets only what is left over, or split it up equal. Tesla won't change the method I suppose, so it's just a fun discussion. I do find it interesting that Tesla decided to go with a hard split on the urban Superchargers. I believe it has more to do with them expecting more owners to use them as a regular charging station and the lower charge rate helps battery longevity.

My ideal solution (if we have to stay with the shared concept) would be to add three more chargers to each paired Supercharger. I believe right now there are 12 in each Supercharger. They always switch in groups of 3. Add three more to each. This way a Model 3 or S/X 100 can charge at 108 kW while there is still 72 kW left for the second car. So when you are alone, you get 120 peak (or whatever your car can do) and when shared, the first one stays at 108 while the second one gets 72 kW. I think that would be a fair compromise.

 

[markb1]

But then you'd have to worry about some moron plugging into your paired stall at an otherwise empty supercharger. Anyways this is way off-topic.

One solution is the change the behavior based on whether the supercharger is mostly full or not.

 

[Helmuth]

They could add a suggestion to the map info which stall you should plug in. You don’t know if a car is almost done with charging until you plug in to the shared stall (if the location is busy).
I think a recommended stall would be a fair compromise to use the location as efficient as possible and you don’t have to worry about someone plugging in next to you (cutting down the power you might get) if you are not waiting at your Tesla...
It could even be a pop up message on your IC or center screen as soon as you enter the Supercharger location!

 

[brkaus]

I see a proposed solution, but I do not see the problem statement?

I don't see a problem with the way it is today. Individual #1 shouldn’t suffer due to knowledge of individual #2.

I would like the car to tell which stall to use. Probably a few choices in order. No way the system would know if a spot is ICEd for example.

If also have to think going full throttle on one to get into the taper quicker would be better overall throughput. Going to have to think about that.

 

[Sasmania]

They could add a suggestion to the map info which stall you should plug in. You don’t know if a car is almost done with charging until you plug in to the shared stall (if the location is busy).
I think a recommended stall would be a fair compromise to use the location as efficient as possible and you don’t have to worry about someone plugging in next to you (cutting down the power you might get) if you are not waiting at your Tesla...
It could even be a pop up message on your IC or center screen as soon as you enter the Supercharger location!

I agree with this...have the car tell us which stall (many new owners don't even know how the A/B works anyway)

But....even better yet....

I suggest giving the owner the option if you want a "Normal Fast Charge" or a "Slower Charge"

Why would anyone want a slower charge? How about not having to run out mid dinner to move the car? Why not pair that person with your more typical person who wants a fast charge?

This coud help both owners get what they want...

 

[brkaus]

Ok, using some very very very simple approximations...
100kWh pack car - S100D or X100D.
Two cars start charging at empty at nearly the same time
Cars can accept 100kW from empty.
Taper starts at 50% charge level (I generally see pretty close to this, but I think the numbers hold either way)

72kW each, they would no longer use the full capacity of the cabinet after ~43 minutes

If one started at 100 and the one plugged in seconds later... they would use the full capacity of the cabinet for 55 minutes.

Using full capacity of the cabinets results in better overall throughput

It's late, so I'm probably looking at this wrong... but...

 

[David99]

Taper starts at 50% charge level (I generally see pretty close to this, but I think the numbers hold either way)

Yes the taper curve starts at 50% but it doesn't drop below 72 kW until aprox 70% SoC.

72kW each, they would no longer use the full capacity of the cabinet after ~43 minutes
If one started at 100 and the one plugged in seconds later... they would use the full capacity of the cabinet for 55 minutes.
Using full capacity of the cabinets results in better overall throughput
It's late, so I'm probably looking at this wrong... but...

I'm not sure how you get to 43 minutes. If the charge power is limited at 72 kW and you have an empty 100 battery you need to charge aprox 50-60 min to charge to 70%. The hardware would be used 100% for the entire time.

With the current switching method, the cars would fill up at different speeds but the overall throughput would be less. Why? Because the way superchargers switch. The individual chargers are connected to the three phases of the grid. They can only switch together. That means if the first car uses just a little more power than a multiple of three, it will use another set of three chargers even though it's only using a small part of it. I know this sounds a little confusing, so here is an example.

Superchargers are made from small individual chargers that each can provide 12 kW. Three always working together because of the three phases of a commercial grid supply. If the car needs 30 kW, it will use three chargers (combined). The other 9 are available to the other car. If the first car uses 37 kW, it gets 36 kW from the first set of 3 chargers and then takes another set of 3 chargers to get the last 1 kW. So the first car uses 6 chargers and the 6 remaining ones are available to the second car. But that means 35 kW of potential power is unused. On average there is always 18 kW unused because of the way it's switching. If the sharing is 50/50 there is no unused power as long as both cars are below 70% SoC.

Here is a post explaining the Supercharing switching.
How pairing at Supercharging works

I should add this is all very theoretical. In my experience, Supercharger sites rarely have the capacity to run at 100% power on all cabinets. When all stalls are in use the power is usually limited due to limits on the grid supply or transformer or the very least, the cabinets are running too hot.

 

[EVSteve]

I agree with this...have the car tell us which stall (many new owners don't even know how the A/B works anyway)

But....even better yet....

I suggest giving the owner the option if you want a "Normal Fast Charge" or a "Slower Charge"

Why would anyone want a slower charge? How about not having to run out mid dinner to move the car? Why not pair that person with your more typical person who wants a fast charge?

This coud help both owners get what they want...

The purpose of superchargers is to deliver as much power as possible in the shortest amount of time to maximize availability.

While your perception is that a installation will not be maxed out during dinner the possibility exists. I personally have gone inside for a snack and 20 minutes later the supercharger, empty when I arrived, now only has two available. This was in the middle of nowhere Pennsylvania, late at night on a Sunday. If I left the restaurant for a few minutes to move my car to make room for others then so can everyone else. With thousands of Model-3s being added to the fleet every week we need the correct mentality in place. The already congested infrastructure is about to be overwhelmed.

 

[ewoodrick]

A little OT... Tesla could change the sharing method on normal Superchargers to be 50/50 when two cars are plugged in giving each 72 kW. If one car draws less or no other car is on the shared stall, it would give 100% power to the car plugged in. This way you would get full power when available but never drop below 72 even when busy.

But then the car that was first charging will take longer to charge. And what you thought was going to be 45 minutes of charging would take over an hour. No surprises if you were the only one plugged in when you arrived.

For the second car, when they plug in, they know they will get at least X, and very probably that will increase when the other car leaves.

When you think about it, you need to think not from the perspective of the second car, but the first, second, and general queuing.

 

[David99]

But then the car that was first charging will take longer to charge. And what you thought was going to be 45 minutes of charging would take over an hour. No surprises if you were the only one plugged in when you arrived.

Same for the second car. The trip planner / navigation told the person you will need to charge for 30 min but when you are the second one on a shared stall, you end up seeing maybe 1/3 of the full power and end up staying twice as long.

There are countless discussions where people reported 'issues' with Superchargers or their cars not getting a slow charge rate at a Supercharger. It's always the second car. I'd say the majority of new owners (and there are thousands now every month) don't know about paired Superchargers.

 

[SigNC]

I like the current way where first plug gets full power and 2nd gets what's left until the other drops down or unplugs. However, what I'd like to see is stalls that aren't paired stay red, and stalls that aren't in use but their paired stall is, turn a color other than red. This way, you don't have to figure out which stall to use, just back into a red stall. If no red stalls, just pick any of the ones already being shared. Could take it a step further and when all pairs have one leg in use the most optimal paired stall could be a different color. Say the one where the other car has already started to taper or is furthest into the taper. Maybe 3 colors is too much?

 

[Sasmania]

The purpose of superchargers is to deliver as much power as possible in the shortest amount of time to maximize availability.

While your perception is that a installation will not be maxed out during dinner the possibility exists. I personally have gone inside for a snack and 20 minutes later the supercharger, empty when I arrived, now only has two available. This was in the middle of nowhere Pennsylvania, late at night on a Sunday. If I left the restaurant for a few minutes to move my car to make room for others then so can everyone else. With thousands of Model-3s being added to the fleet every week we need the correct mentality in place. The already congested infrastructure is about to be overwhelmed.

I'm talking about the system intelligently allowing for someone to take the slower charge....and allow someone else the faster charge so that both people get what they want. It doesn't change the overall combined charging time of the 2 cars in question. All it is doing is allowing you to say you want to be the person getting the slower charge...even if you are the first one there of the 2.

 

[FlatSix911]

They could add a suggestion to the map info which stall you should plug in. You don’t know if a car is almost done with charging until you plug into the shared stall (if the location is busy).

I think a recommended stall would be a fair compromise to use the location as efficient as possible and you don’t have to worry about someone plugging in next to you (cutting down the power you might get) if you are not waiting at your Tesla...
It could even be a pop-up message on your IC or center screen as soon as you enter the Supercharger location!

I see a proposed solution, but I do not see the problem statement?
I don't see a problem with the way it is today. Individual #1 shouldn’t suffer due to knowledge of individual #2.

I would like the car to tell which stall to use. Probably a few choices in order. No way the system would know if a spot is ICEd for example. If also have to think going full throttle on one to get into the taper quicker would be better overall throughput. Going to have to think about that.

A very good idea... now to tweet Elon

 

[David99]

Othe other hand it is better to have 20 shared stalls rather than only 10 with full power. It's much preferable to be able to plug in and do something else rather than having to wait in line.

I think Tesla should have an easy way to show arriving cars what stall has the most power available.