High-usage supercharger station

[Big Earl]

Yeah, it's a huge undertaking. But in principle, there's no reason they can't add additional transformers to handle the extra capacity required, then convert it a piece at a time.

For example, if they have a supercharger on 3-phase 480V service at 150 kW per pair, at 312.5-ish amps per pair, they need roughly 1875A, so it probably has at least 2000A service (6 pairs * 300 amps).

For a V3 supercharger, they would need 250 kW per station, which turns out to be about 520 amps per station. So they could use the existing service to feed at least three V3 supercharger stations (and maybe four, depending on how accurate that 2000A guess is). If they wire up additional transformers, they could convert most of the stations a few at a time and add them to the new service, then wire up the last few stations to the old service.

What you're suggesting is hugely expensive with limited reward. V3 only helps existing long range Model 3 vehicles, and then, only below about 40% state of charge. Once you're into the taper, it's no faster than a 150 kW V2 station, despite investing large amounts of money into upgrading the electrical service.

V3 is really best on interstate travel routes where you're looking to "splash and go." In cities and suburban areas, people are looking for higher states of charge where V3 doesn't really help, the exception being travelers who are looking to "splash and go" as they travel through the city.

V3's high power output will only be fully-utilized by future vehicles with larger batteries like the pickup truck, roadster and semi. Possibly a future S/X refreshed with an improved battery cooling system (this can be done while retaining the 18650 cell format, if that's what Tesla wants to stick with, as it seems they do).

Finally, a little anecdote: my long trip charging stops are currently under 20 minutes on average with a long range Model 3 and 145 kW charge rate. There is only so much faster you can make a bio break before getting back on the road, so increasing charging speed is going to have diminishing returns on reducing my charging stop time. For the current fleet, the best value is more chargers, not faster ones. That said, not having to share power on V3 will help improve vehicle throughput.

Just my $0.02 on the matter.

 

[cpa]

Finally, a little anecdote: my long trip charging stops are currently under 20 minutes on average with a long range Model 3 and 145 kW charge rate. There is only so much faster you can make a bio break before getting back on the road, so increasing charging speed is going to have diminishing returns on reducing my charging stop time. For the current fleet, the best value is more chargers, not faster ones. That said, not having to share power on V3 will help improve vehicle throughout.

I think this is as good an explanation as any. I found as I drove to Cincinnati that the Superchargers are staggered about 75 to 110 miles apart on I40 east of Albuquerque to OKC, then similarly up I44 to St. Louis. A charge to 60% in our '14 Model S would require about 25 minutes or so to charge from 15-20% back up to 60-65%. This made for a refreshing stop, short walk, bio break, and about a 5 minute wait in the car before unplugging. My max rate is around 117kW <~22% SOC. Around 50% SOC the rate is around 60kW, plummeting pretty fast after that.

Things are a little more problematic in the West. The highways have much longer stretches of limited charging locations, so the pattern I experienced driving to Cincinnati was not available returning home mostly along Interstate 80. Those legs are longer, 120-150 miles apart. Infilling these gaps would allow the 20-25 minute stop. Because these SC do not usually receive a lot of heavy usage, and because suitable locations between existing locations are few, I would surmise that Tesla has no immediate plans to add new charging locations; instead it will expand the existing sites or find a new site in the same community.

 

[dgatwood]

What you're suggesting is hugely expensive with limited reward. V3 only helps existing long range Model 3 vehicles, and then, only below about 40% state of charge. Once you're into the taper, it's no faster than a 150 kW V2 station, despite investing large amounts of money into upgrading the electrical service.

That simply isn't true, because a V2 station doesn't give every car 150 kW; in fact, it doesn't give any single car 150 kW. Rather, it gives you up to 145 kW per car, but only if the paired bay is empty. The pairing difference matters far more than the peak kW difference, because it means that a V2 station is effectively a 75 kW supercharger, on average.

The Bay Area superchargers stay 100% full for several hours per day, which means you're always sharing a charger with another vehicle. If you get lucky, and the other vehicle is nearly charged, you can charge quickly in that configuration, because it gives you up to 145 kW. If you get unlucky, and the other vehicle just pulled in, the other vehicle gets its charging speed cut to 120 kW, but you get only 30 kW.

Yesterday, I experienced the difference between a worst-case shared V2 supercharger and an unshared V2 supercharger first-hand. For some reason, my car glitched and disconnected from the supercharger at about a 17% state-of-charge in Mountain View. The other bay had a car that pulled in two minutes after me, and when my car glitched, that other car got 120 kW, and I got kicked down to 30 kW. At that speed, it estimated that it would take 50 minutes to charge to 90%.

At that point, I realized that I needed to buy something at Target anyway, so I checked the map, and bizarrely, the Sunnyvale supercharger ten miles away had five empty slots. So I drove over there and plugged into the empty spot paired with the handicapped bay, which gave me unpaired charging speed for the entire time. It took 30 minutes to charge, even with the extra ten miles spent driving over there.

So even if Tesla never releases an update to enable faster supercharging speeds at V3 superchargers on the Model S or Model X, a V3 supercharger would still sometimes shave up to 40% off of your charging time. And when a supercharger is full all day, every day, that translates to a noticeably higher total vehicle throughput.

 

[MorrisonHiker]

Yesterday, I experienced the difference between a worst-case shared V2 supercharger and an unshared V2 supercharger first-hand. For some reason, my car glitched and disconnected from the supercharger at about a 17% state-of-charge in Mountain View. The other bay had a car that pulled in two minutes after me, and when my car glitched, that other car got 120 kW, and I got kicked down to 30 kW. At that speed, it estimated that it would take 50 minutes to charge to 90%.

Were you in your car when this happened? If not (or you weren't paying attention), the "glitch" could've been intentional.

 

[David99]

Maybe V3

That simply isn't true, because a V2 station doesn't give every car 150 kW; in fact, it doesn't give any single car 150 kW. Rather, it gives you up to 145 kW per car, but only if the paired bay is empty. The pairing difference matters far more than the peak kW difference, because it means that a V2 station is effectively a 75 kW supercharger, on average.

The Bay Area superchargers stay 100% full for several hours per day, which means you're always sharing a charger with another vehicle. If you get lucky, and the other vehicle is nearly charged, you can charge quickly in that configuration, because it gives you up to 145 kW. If you get unlucky, and the other vehicle just pulled in, the other vehicle gets its charging speed cut to 120 kW, but you get only 30 kW.

Reality is often even worse. Those last few months I tried to peek into the other car that shared a charger. Regardless of what the ratio was between the two cars, it never added up to 120 kW or even more like the theory might suggest. Most of the time the combined power was around 100 kW. It makes sense as they switch in groups of 3 chargers. For example if a car draws 50 kW, it still uses 6 chargers. They could theoretically deliver 72 kW but since the car can only take 50, 22 kW are 'lost'.

The concept of sharing power was OK in the beginning when few cars where on the road, charge rates were lower and would taper off faster. Today it underdelivers in most cases.

 

[jerry33]

The concept of sharing power was OK in the beginning when few cars where on the road, charge rates were lower and would taper off faster. Today it underdelivers in most cases.

In California. At most places that I travel to I'm lucky if I see one other car charging at the same time I am.

 

[Big Earl]

Maybe V3


Reality is often even worse. Those last few months I tried to peek into the other car that shared a charger. Regardless of what the ratio was between the two cars, it never added up to 120 kW or even more like the theory might suggest. Most of the time the combined power was around 100 kW. It makes sense as they switch in groups of 3 chargers. For example if a car draws 50 kW, it still uses 6 chargers. They could theoretically deliver 72 kW but since the car can only take 50, 22 kW are 'lost'.

The concept of sharing power was OK in the beginning when few cars where on the road, charge rates were lower and would taper off faster. Today it underdelivers in most cases.

It switches in four groups of three 12 kW charging units, for a nominal output of 36/72/108/144 kW. If a charger or pedestal isn't performing up to spec, you'll get less. If the whole site is full and the transformer is the limiting factor, you'll see less. If site voltage is lower than nominal (<480 volts), you'll see less. If site voltage is higher than nominal (>480 volts), you'll get more than the expected output (example, some people seeing 150 kW at a V2 station or urban chargers providing 75 kW).

 

[David99]

In California. At most places that I travel to I'm lucky if I see one other car charging at the same time I am.

Yeah I never have issues driving through Nebraska or South Dakota either
Saying there is no issue in less frequented areas isn't helping. It's like having a bad rash on your arm and the doctor tells you, 'hey, your legs looks fine'.

 

[Pruitt]

I ran into that same "limitation" yesterday at a supercharger in New Jersey. The station was less than half full.
This is another Tesla "upgrade" that makes the owners have to take extra steps in using the car. Like having the stupid media player pop up every time you get into the car, now every time you charge at a "high-usage" supercharger - I'll best it's most of them - you have to reset the charge limit to what you actually want / need.

This kind of bullpuckey really impacts enjoyment of the car at times.