How pairing at Supercharging works

[Saghost]

I think the impact of the charging load on the utilities is a bit overstated. Montgomery county Maryland is one of the richest and highly populated counties in the US. It has exactly one Supercharging station. That station could turn on 100% and back off again every hour and the power company would not even notice. EV charging is so inconsequential to the power grid that it means pretty much nothing.

Here in the US the utilities have higher charges for customers that have more erratic usage in that they charge based on peak consumption. But that is not likely to mean it would be profitable for Tesla to install battery packs. Consider they would need an equivalent pack for every car that is charging during the four hour peak time. That's a lot of batteries and right now they want to put every one they can make into cars.

Yup. Whether a battery makes sense will depend greatly on the policies/pricing of the local utility and the site utilization pattern.

Presumably the current cell shortage will be resolved /more production coming on line before too long.

 

[Rocky_H]

I think the impact of the charging load on the utilities is a bit overstated.

It's only about "load on the utilities" tangentially. It's really about billing. You seem to be not understanding the point.

Montgomery county Maryland is one of the richest and highly populated counties in the US. It has exactly one Supercharging station. That station could turn on 100% and back off again every hour and the power company would not even notice. EV charging is so inconsequential to the power grid that it means pretty much nothing.

You are addressing something that's not the issue. No one is claiming the sky is falling that anything is going to black out neighborhoods or hurt the power grid, as you are claiming.
But the utilities DO monitor large customers' peak power levels and have scales of hitting them for some very expensive rates if they hit certain peak power levels. So if Tesla can keep their peak levels down at their transformer draw from the utility, and then at a step beyond that connection, buffer it and provide the peak power bursts from stored energy, it can greatly reduce their demand charges and probably save them a good bit of money.

 

[gnuarm]

It's only about "load on the utilities" tangentially. It's really about billing. You seem to be not understanding the point.

I do understand that and I have tried to make the point before that the billing is not a significant issue for Tesla either. Unlike many facilities that have high startup surges on motors the Superchargers have entirely contained maximum power draws. A friend who worked at a milk processor staged several motors so they started up in sequence rather than together to minimize the power surge because of the high billing for the entire month. I have talked about the billing before. It would be good if you read the entire thread rather than replying to a single message.

You are addressing something that's not the issue. No one is claiming the sky is falling that anything is going to black out neighborhoods or hurt the power grid, as you are claiming.
But the utilities DO monitor large customers' peak power levels and have scales of hitting them for some very expensive rates if they hit certain peak power levels. So if Tesla can keep their peak levels down at their transformer draw from the utility, and then at a step beyond that connection, buffer it and provide the peak power bursts from stored energy, it can greatly reduce their demand charges and probably save them a good bit of money.

Exactly. Utilities monitor the LARGE customers. Tesla is not a large customer as I have explained clearly. Tesla Superchargers don't really have a "peak" draw in the same way other users do. They draw a maximum of 144 kW per Supercharger pair, period. No need to go on about how to mitigate this. That's what they are designed to do and that is how they will be billed. Locations like Gaithersburg, which often has nearly all if not all stations occupied, will draw the maximum during peak times. That's the reality.

You are the only person talking about blacking "out neighborhoods". Don't be ridiculous and don't put words in my mouth.

 

[Rocky_H]

I do understand that and I have tried to make the point before that the billing is not a significant issue for Tesla either.

I am pretty sure it is. The levels of power Tesla uses are extremely high--higher than even most of the commercial retail types of locations where they are hosted.

Unlike many facilities that have high startup surges on motors the Superchargers have entirely contained maximum power draws.

...that are still REALLY high. It's not like it's some arcing surge. It's just really high power levels for tens of minutes at a time. That will still put them into some expensive demand charges.

It would be good if you read the entire thread rather than replying to a single message.

I have already read all of this thread, but to see you still saying such incorrect things about it shows that you still don't understand it.

Exactly. Utilities monitor the LARGE customers. Tesla is not a large customer as I have explained clearly.

...clearly wrong. Tesla is a HUGE electricity customer. The sites need to arrange for their own very large transformer from the utility. They are capable of power levels in the 1 to 2 or more megawatts, and certainly more for the 40 site locations. Any megawatt scale customer is absolutely a large customer that is monitored and assessed by demand charges. This fact that you think Tesla Supercharger sites are not a large customer of the utilities show that you have no clue about this.

Tesla Superchargers don't really have a "peak" draw in the same way other users do. They draw a maximum of 144 kW per Supercharger pair, period. No need to go on about how to mitigate this.

I saw you kind of mention this earlier, and I thought, "Surely he doesn't misunderstand it that badly. He thinks each stall is a customer?" More likely you seem to think that the word "peak" only applies to some outlandish momentary insanely high spike for less than a second. That's not what this is about. Peak power for demand charge can still bite hard for these longer periods of 144kW because sites have 10 or 20 or 40 stalls, and their accumulated power can be really high when a lot of cars are there and much lower when few cars are there. See where the "peaks" and "valleys" are in this scenario?

That's what they are designed to do and that is how they will be billed. Locations like Gaithersburg, which often has nearly all if not all stations occupied, will draw the maximum during peak times. That's the reality.

How they will be billed is by what their peak power level is during the year. If Tesla can buffer that by battery storage to serve those peak loads themselves instead of drawing those peak loads, then they reduce their top power level that applies all year long, and that saves them significant money. Since they are already doing this, it is obviously already useful and important to them. So let me illustrate:

You want to refer to Gaithersburg, MD? OK, let's use that example--that's 12 stalls. If those are all full, and some mix of charging speeds from the cars, but pretty much assuming all the power is split however it can go, that's 144 kW times 6. That's 864 kW peak when all of the equipment is running full-out. If they put in some large battery storage, they could cover those full times from battery and refill it at other off-peak times, and even keep a steady draw from the utility that is less than that 864 kW. So by letting it ebb and flow and feeding the top load from the battery, they may be able to reduce it so they never draw higher than 300 kW or 400 kW from the utility at any point. That reduces their maximum peak load and keeps that site cheaper to run.

You are the only person talking about blacking "out neighborhoods".

You were the one talking about whether it would be hard on the power grid, like so:

That station could turn on 100% and back off again every hour and the power company would not even notice. EV charging is so inconsequential to the power grid that it means pretty much nothing.

They will "notice" in their accounting department so far as logging the peak power to apply that tier to Tesla's bill.

Don't be ridiculous and don't put words in my mouth.

So yeah, those were my words to your idea. Granted, I used some hyperbole to snark on your idea a bit--sorry.

 

[gnuarm]

I am pretty sure it is. The levels of power Tesla uses are extremely high--higher than even most of the commercial retail types of locations where they are hosted.

The type of commercial locations vary greatly. The lowest power consumption I've charged at was probably a Sheetz or Wawa gas station. The highest were malls and an airport. I assume you are referring to a gas station. Not a very relevant point really. I kinda doubt the Tesla chargers are even noticed at airports or malls.

...that are still REALLY high. It's not like it's some arcing surge. It's just really high power levels for tens of minutes at a time. That will still put them into some expensive demand charges.

The pricing doesn't care how much electricity you use. At least in Maryland, the electric company sets the rate for commercial establishments based on their peak usage. That's why I explained how the company sequenced motor starts.

I have already read all of this thread, but to see you still saying such incorrect things about it shows that you still don't understand it.

Well please educate me with some facts you can support.

...clearly wrong. Tesla is a HUGE electricity customer. The sites need to arrange for their own very large transformer from the utility. They are capable of power levels in the 1 to 2 or more megawatts, and certainly more for the 40 site locations. Any megawatt scale customer is absolutely a large customer that is monitored and assessed by demand charges. This fact that you think Tesla Supercharger sites are not a large customer of the utilities show that you have no clue about this.

There are very few stations with 40 units. Most are 10 or 12 and some as high as 16. Beyond that is much less common.

"obviously"... means you don't actually know anything about it. The mall they are located by uses much, much more electricity than that.

I saw you kind of mention this earlier, and I thought, "Surely he doesn't misunderstand it that badly. He thinks each stall is a customer?" More likely you seem to think that the word "peak" only applies to some outlandish momentary insanely high spike for less than a second. That's not what this is about. Peak power for demand charge can still bite hard for these longer periods of 144kW because sites have 10 or 20 or 40 stalls, and their accumulated power can be really high when a lot of cars are there and much lower when few cars are there. See where the "peaks" and "valleys" are in this scenario?

You seem to be very confused about what I wrote.

How they will be billed is by what their peak power level is during the year. If Tesla can buffer that by battery storage to serve those peak loads themselves instead of drawing those peak loads, then they reduce their top power level that applies all year long, and that saves them significant money. Since they are already doing this, it is obviously already useful and important to them. So let me illustrate:

How much money is significant? You keep saying these things, but you don't actually have any info about the details.

Tell me this. If Tesla could save so much money by reducing their peak loads, why haven't they done it? Is Tesla too stupid to save money?

You want to refer to Gaithersburg, MD? OK, let's use that example--that's 12 stalls. If those are all full, and some mix of charging speeds from the cars, but pretty much assuming all the power is split however it can go, that's 144 kW times 6. That's 864 kW peak when all of the equipment is running full-out. If they put in some large battery storage, they could cover those full times from battery and refill it at other off-peak times, and even keep a steady draw from the utility that is less than that 864 kW. So by letting it ebb and flow and feeding the top load from the battery, they may be able to reduce it so they never draw higher than 300 kW or 400 kW from the utility at any point. That reduces their maximum peak load and keeps that site cheaper to run.

But how much cheaper? How many batteries would they need to install at what cost? Tesla charges $22,000 for a 100 kWh battery pack. To reduce the load at Gaithersburg to 400 kW would likely require about 24 packs along with the associated charging gear. So let's say $600,000. That's a lot of kWh costs that would need to be saved!!!

Then if for just one time during the month your batteries run down and your peak usage ramps up, you will pay the higher price for the entire month.

You were the one talking about whether it would be hard on the power grid, like so:

They will "notice" in their accounting department so far as logging the peak power to apply that tier to Tesla's bill.

They don't care how many times you ramp up and down. They care about the peak usage during the entire month which sets the rate which is multiplied by the total electrical draw. At least this is what I was told by the guy who sequenced the motors.

So yeah, those were my words to your idea. Granted, I used some hyperbole to snark on your idea a bit--sorry.

Some? Lol Whatever. It's just a discussion.

 

[Rocky_H]

Tell me this. If Tesla could save so much money by reducing their peak loads, why haven't they done it? Is Tesla too stupid to save money?

If you don't realize that Tesla already values this so much that they are doing it at 20+ sites already, it's not worth continuing to try to educate you. They will continue to do it more as they have enough battery capacity to spare for it.
Do Supercharger sites have stationary battery storage?

 

[gnuarm]

If you don't realize that Tesla already values this so much that they are doing it at 20+ sites already, it's not worth continuing to try to educate you. They will continue to do it more as they have enough battery capacity to spare for it.
Do Supercharger sites have stationary battery storage?

Where did this info come from? Some guy posting it in a thread is not exactly a reliable source. I would expect this to be reported in the press or on the web site.

BTW, you don't need to get offensive. If you don't want to discuss this, then don't. Just don't be rude.

 

[Saghost]

Where did this info come from? Some guy posting it in a thread is not exactly a reliable source. I would expect this to be reported in the press or on the web site.

BTW, you don't need to get offensive. If you don't want to discuss this, then don't. Just don't be rude.

An article like this, maybe?

Tesla plans to disconnect ‘almost all’ Superchargers from the grid and go solar+battery, says Elon Musk

Or this?

Tesla Supercharger stays online in power outage thanks to Powerpack system

Maybe even something like this?

Volkswagen’s Electrify America will buy Tesla Powerpacks to manage peak demand

Folks who have been paying attention for a while know Tesla has installed them at a number of sites, but not the majority - presumably at the sites where demand charges or infrastructure limits made them useful.

 

[Rocky_H]

BTW, you don't need to get offensive. If you don't want to discuss this, then don't. Just don't be rude.

OK, I do apologize for letting my frustration boil over. Dealing with this kind of arrogant resistance to information is one of my hot buttons I guess.

 

[gnuarm]

An article like this, maybe?

Tesla plans to disconnect ‘almost all’ Superchargers from the grid and go solar+battery, says Elon Musk

Or this?

Tesla Supercharger stays online in power outage thanks to Powerpack system

Maybe even something like this?

Volkswagen’s Electrify America will buy Tesla Powerpacks to manage peak demand

Folks who have been paying attention for a while know Tesla has installed them at a number of sites, but not the majority - presumably at the sites where demand charges or infrastructure limits made them useful.

Ok, this proves it is theoretically possible which we all knew. One article you list isn't even about Tesla Superchargers, another is about Musk tweets (typical hyperbole) regarding adding solar and the other says, "They now operate over 1,000 Supercharger stations around the world, but only a few are known to have solar panels or Powerpacks."

So while there may be a small handful of Superchargers with battery supplement, this myth is largely busted.

This is not on topic here and there is no real value in continuing to argue the point.

 

[gnuarm]

OK, I do apologize for letting my frustration boil over. Dealing with this kind of arrogant resistance to information is one of my hot buttons I guess.

I like that. An apology is coupled to further insult. lol

 

[Saghost]

Ok, this proves it is theoretically possible which we all knew. One article you list isn't even about Tesla Superchargers, another is about Musk tweets (typical hyperbole) regarding adding solar and the other says, "They now operate over 1,000 Supercharger stations around the world, but only a few are known to have solar panels or Powerpacks."

So while there may be a small handful of Superchargers with battery supplement, this myth is largely busted.

This is not on topic here and there is no real value in continuing to argue the point.

Seriously?

Wow.

So the fact that EA is planning to install batteries for the specific purpose of shaving demand charges is irrelevant to the discussion of whether Tesla might install batteries to reduce demand charges, and articles showing that Tesla has installed powerpacks at some locations result in the myth that Tesla installs them at some locations being largely busted?

That's some seriously creative logic right there.

 

[Saghost]

Where did this info come from? Some guy posting it in a thread is not exactly a reliable source. I would expect this to be reported in the press or on the web site.

BTW, you don't need to get offensive. If you don't want to discuss this, then don't. Just don't be rude.

How about a video of a keynote speech five years ago in which Tesla's chief technical officer made a presentation about how they are saving on demand charges by installing a battery pack at Tejon Ranch with detailed examples of one day of usage and how the pack reduced the load and discussion of demand charges?

Would that be adequate evidence that Tesla cares about it and that it could help Tesla?

(The relevant part starts about 24 minutes in.)

 

[Fiver]

Reading the last two pages of this thread.....

 

[israndy]

Do people actually read threads when this happens? I scroll and scroll and if it gets to beyond two pages I start pulling out the ignore button. Although no one is probably reading this reply as people likely set me to Ignore long ago.

-Randy

 

[David99]

A few days ago I saw someone post on a FB group that pairing at Superchargers has recently been changed in a way that it's more equal rather than first car getting max and the second car only what's left over. I was skeptical at first so I payed close attention to the charge rate of my car and the other one that was on the same shared pair. It does look like the split is now 50/50. I was plugged in with a low battery, got over 80 kW and the second car came. At first he only got 20 kW, then both our cars hoovered around 40 kW each even though I had plugged in a few minutes earlier and both our batteries were rather empty. The reason we each only got 40 kW was because the site was full and it's known to slow down when all stalls are in use.

I will try to keep an eye on the charge rate when on paired stalls at other sites to see if that's the new way pairing works now. If anyone else has a chance, try to peak into the other car (maybe ask ahead so it doesn't look creepy LOL) and see what the charge rates are.

 

[israndy]

It is a shame that Tesla doesn't support lighting up the center screen when non-owners touch the outside, like touching the door handles or the button on the charger plug. Obviously, don't open the car, but it would be nice to respond and let others know how fast you are charging and how close to being done you are.

Perhaps I just cannot think of the reason one would want the privacy. The only thing I can think is people don't want to move their car when it's finished charging, but that's a dick move. If you are done, we should know, so we can soap your windshield.

 

[HankLloydRight]

Yeah, it's a frustrating crap-shoot. This week I pulled into Strasburg, VA -- 6 stalls, three were properly taken 1A, 2A, 3B. I had no idea which one to choose.. so I randomly picked 2A where a red MX was charging. It would be nice to have some indicator at so the most optimal open stall to pull into. Tesla could easily do this on the Nav map.

At first I got 40kW, then 70kW, which was good, but not great, and then I think it jumped up to 90kW for a short bit, but never higher. I was there for an hour. I went to have lunch at the Denny's right there - DO NOT GO THERE. It was horrible service, which I won't get into. I'll make sure I can stop at either Martinsburg or Mt Jackson on my next trip down that way and avoid Strasburg all together.

 

[meomyo]

Yeah, it's a frustrating crap-shoot. This week I pulled into Strasburg, VA -- 6 stalls, three were properly taken 1A, 2A, 3B. I had no idea which one to choose.. so I randomly picked 2A where a red MX was charging. It would be nice to have some indicator at so the most optimal open stall to pull into. Tesla could easily do this on the Nav map.

At first I got 40kW, then 70kW, which was good, but not great, and then I think it jumped up to 90kW for a short bit, but never higher. I was there for an hour. I went to have lunch at the Denny's right there - DO NOT GO THERE. It was horrible service, which I won't get into. I'll make sure I can stop at either Martinsburg or Mt Jackson on my next trip down that way and avoid Strasburg all together.

did u unplug the red model x???

 

[Big Earl]

A few days ago I saw someone post on a FB group that pairing at Superchargers has recently been changed in a way that it's more equal rather than first car getting max and the second car only what's left over. I was skeptical at first so I payed close attention to the charge rate of my car and the other one that was on the same shared pair. It does look like the split is now 50/50. I was plugged in with a low battery, got over 80 kW and the second car came. At first he only got 20 kW, then both our cars hoovered around 40 kW each even though I had plugged in a few minutes earlier and both our batteries were rather empty. The reason we each only got 40 kW was because the site was full and it's known to slow down when all stalls are in use.

I will try to keep an eye on the charge rate when on paired stalls at other sites to see if that's the new way pairing works now. If anyone else has a chance, try to peak into the other car (maybe ask ahead so it doesn't look creepy LOL) and see what the charge rates are.

In my recent experience, the system hasn't changed. It still allocates chargers in four groups 36 kW as I've described previously. It's hard to tell what's really going on at sites that are full or in need of maintenance. Test at a relatively empty site that's known to provide full power... also need a car that can pull full power (long range Model 3) to properly test.