(It’s early and I probably calculated this on the wrong napkin, but) the smallest EV battery (in the mini cooper) claims a capacity of ~29kWh. Supplying this power in 10 minutes would require 170kW. If the supply is 240 volts single phase and perfect power factor, that would require over 700 amps.
Who knew old Doc from Back to the Future was building a Toyota Fast Charger the whole time. It’s crazy that all Toyota has needed all this time is to change their flux capacitor fluid.
DC fast charging, which this almost certainly refers to, isn’t done at 240 it’s done at the pack voltage which is usually between 300 and 900v. Most cars use 400v, Hyundai and Kia use 800v. The Hummer EV (and other forthcoming big GM vehicles) uses a clever pack that operates at 400v but can switch from parallel to series and charge at 800v. The “good” chargers go up to 1000v 500a.
So to get that same roughly 170kw at 400v is 425a - so a lot of chargers already exist that could handle a 30kwh pack just fine.
At full tilt 1000v 500a a charger could deliver roughly 80kwh in 10 minutes, (assuming it didn’t limit itself because of the heat) which is a lot but it’s not getting you 700 miles of range.
Watts is watts though. You can convert to any voltage you’d like, but short of reinventing the grid or only installing chargers at electrical sub stations, I don’t see how the grid can supply the required power at any kind of localized level. People can claim whatever they like for the standards that the converter is capable of, but ultimately the wires supplying mains voltage have a very real limit and can not supply massive amounts of current. Even in industry, power is increased by adding phases first, then increasing voltage second, because reinventing the grid to supply massive amounts of current is just not practical. So now what, are we going to pipe 10k7 volts to charge batteries? That’s “pick up the pieces” level of dead when the average idiot makes a mistake anywhere remotely close to the thing. If you want to try with 3 phase 480, now you have a tremendous amount of heat to deal with along with a bunch of extra complexity that isn’t needed. You also need the same local power infrastructure as most large businesses and industrial sites. That won’t be available in most of outskirt suburbia where demand will be the highest.
I don’t think the intention is for the average home to charge at these rates, but rather for charging stations to be faster. In large part even with 350kw DC fast charging stations (which already exist) the battery is the limiting factor, not the charger.
Essentially, yes these would kind of only be installed at electrical sub stations.
The stations that are already capable of 350kW must be using additional on site static storage that is able to supply this kind of power. Otherwise, it is junk marketing of design capacity and safety margins instead of real world limitations. Most homes in the USA have 240V with a 100A main breaker, and only if the home/local grid is relatively modern. Many homes only have 40A or 60A main breakers. It is impossible for 240V/100A to exceed 24kW under any circumstances other than breaking the physics of the entire universe. The only way to supply more power is to add local storage. 350kW is a lot of storage and engineering in practice to deliver. I’m willing to bet most of these setups are not performing anywhere near this. Heck any old average wall wort from your junk drawer will have a full bridge rectifier with 4× 1N4007 diodes. Those are rated at 1kV at 1A. By modern marketing standards they’d call that a 4A 4kV power supply. In the real world, that thing is pumping a massive 500mA at 5V and those diodes are probably still going to fail eventually.
Watts are the hard power limit that can’t be changed. The volts and current can seesaw against each other in a converter or transformer, but the combination can never alter the total available watts. Most people are not going to be able to buy an electric vehicle AND a massive static local supply source capable of high current output.
If you want centralized infrastructure, the scale of local storage is massive, nearly as much as everyone’s home solution combined, or it involves extremely high voltage distribution lines with extremely skilled labor managing it, or lots of dead people. I doubt the distribution line infrastructure can handle the types of loading that such random high current loads would induce. It would probably require massive local buffering infrastructure like momentum wheels to maintain the grid specification while multiple batteries are simultaneously charged at random. Any infrastructure requiring additional local storage must also justify itself against the fact that all of the EV batteries are not economically recyclable. Doubling the battery count for more convenient charging is just exchanging one environmental catastrophe with fossil fuel for another, even more so than it is already.
It uses 480v three phase at up to 440a to accomplish it. No one is going to get that in a residential setting. The unit itself probably costs on the order of $200k, and that wouldn’t include the construction of the site or any installation costs from the electrical company.
(It’s early and I probably calculated this on the wrong napkin, but) the smallest EV battery (in the mini cooper) claims a capacity of ~29kWh. Supplying this power in 10 minutes would require 170kW. If the supply is 240 volts single phase and perfect power factor, that would require over 700 amps.
Who knew old Doc from Back to the Future was building a Toyota Fast Charger the whole time. It’s crazy that all Toyota has needed all this time is to change their flux capacitor fluid.
DC fast charging, which this almost certainly refers to, isn’t done at 240 it’s done at the pack voltage which is usually between 300 and 900v. Most cars use 400v, Hyundai and Kia use 800v. The Hummer EV (and other forthcoming big GM vehicles) uses a clever pack that operates at 400v but can switch from parallel to series and charge at 800v. The “good” chargers go up to 1000v 500a.
So to get that same roughly 170kw at 400v is 425a - so a lot of chargers already exist that could handle a 30kwh pack just fine.
At full tilt 1000v 500a a charger could deliver roughly 80kwh in 10 minutes, (assuming it didn’t limit itself because of the heat) which is a lot but it’s not getting you 700 miles of range.
Watts is watts though. You can convert to any voltage you’d like, but short of reinventing the grid or only installing chargers at electrical sub stations, I don’t see how the grid can supply the required power at any kind of localized level. People can claim whatever they like for the standards that the converter is capable of, but ultimately the wires supplying mains voltage have a very real limit and can not supply massive amounts of current. Even in industry, power is increased by adding phases first, then increasing voltage second, because reinventing the grid to supply massive amounts of current is just not practical. So now what, are we going to pipe 10k7 volts to charge batteries? That’s “pick up the pieces” level of dead when the average idiot makes a mistake anywhere remotely close to the thing. If you want to try with 3 phase 480, now you have a tremendous amount of heat to deal with along with a bunch of extra complexity that isn’t needed. You also need the same local power infrastructure as most large businesses and industrial sites. That won’t be available in most of outskirt suburbia where demand will be the highest.
I don’t think the intention is for the average home to charge at these rates, but rather for charging stations to be faster. In large part even with 350kw DC fast charging stations (which already exist) the battery is the limiting factor, not the charger.
Essentially, yes these would kind of only be installed at electrical sub stations.
The stations that are already capable of 350kW must be using additional on site static storage that is able to supply this kind of power. Otherwise, it is junk marketing of design capacity and safety margins instead of real world limitations. Most homes in the USA have 240V with a 100A main breaker, and only if the home/local grid is relatively modern. Many homes only have 40A or 60A main breakers. It is impossible for 240V/100A to exceed 24kW under any circumstances other than breaking the physics of the entire universe. The only way to supply more power is to add local storage. 350kW is a lot of storage and engineering in practice to deliver. I’m willing to bet most of these setups are not performing anywhere near this. Heck any old average wall wort from your junk drawer will have a full bridge rectifier with 4× 1N4007 diodes. Those are rated at 1kV at 1A. By modern marketing standards they’d call that a 4A 4kV power supply. In the real world, that thing is pumping a massive 500mA at 5V and those diodes are probably still going to fail eventually.
Watts are the hard power limit that can’t be changed. The volts and current can seesaw against each other in a converter or transformer, but the combination can never alter the total available watts. Most people are not going to be able to buy an electric vehicle AND a massive static local supply source capable of high current output.
If you want centralized infrastructure, the scale of local storage is massive, nearly as much as everyone’s home solution combined, or it involves extremely high voltage distribution lines with extremely skilled labor managing it, or lots of dead people. I doubt the distribution line infrastructure can handle the types of loading that such random high current loads would induce. It would probably require massive local buffering infrastructure like momentum wheels to maintain the grid specification while multiple batteries are simultaneously charged at random. Any infrastructure requiring additional local storage must also justify itself against the fact that all of the EV batteries are not economically recyclable. Doubling the battery count for more convenient charging is just exchanging one environmental catastrophe with fossil fuel for another, even more so than it is already.
Again, large DC fast chargers are not for individual homes. Home 240v EVSEs run about 5-10kw and cost $500ish.
350kw chargers do exist and are not just marketing - they just aren’t being installed normal people’s houses. Here’s a DC fast charger for sale:
https://www.power-sonic.com/product/evdc-360na/
It uses 480v three phase at up to 440a to accomplish it. No one is going to get that in a residential setting. The unit itself probably costs on the order of $200k, and that wouldn’t include the construction of the site or any installation costs from the electrical company.