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Electricity meters have been known for decades, even with payment terminals.after all, they were invented to bill customers for electricity used. And I can see

Electricity meters have been known for decades, even with payment terminals.after all, they were invented to bill customers for electricity used. And I can see authors point - if you look at Tesla chargers, it's not only the stalls but whole underground infrastructure with cooling, air conditioners and who knows what else. If cars were designed to use AC instead it would be enough to have an AC outlet (3 phase probably) and a meter, and whole charging station could be built by an electrician, with standard components. Yep you won't get a megawatt power this way, but 30-50kW is realistic

vel0city 3y ago
Yeah but even adding a credit card terminal massively increases the complexity compared to the plain plug the author is talking about here. If you're going to have to include relays and ground fault equipment and payment systems you're 95% of the way to a "complicated" EVSE.
stetrain 3y ago
So the power meter dutifully ticks up the charge you have used while plugged in. Then what? How do you pay it? Do you have to go track down some person who may or may not be on duty to read the meter, hope they read it before you started, and pay them in quarters? Cars are designed to use AC. That's how all current Level 2 chargers work. They are basically dumb outlets plus a contractor, GFCI, and optionally a payment terminal. But beyond a certain level (around 20kW) the size and cost of putting a larger AC to DC converter in the car is prohibitive. At one point Tesla Superchargers were literally racks of the same AC to DC converters found in the car, but fed with 3-phase power, bussed together, and cooled all external to the car. There's no other way to implement a reliable 20-minute roadtrip charge.
- lafar6503 3y ago
  Oh come on, pay for use is a solved problem. Look at gas pumps. But if it's not feasible to have a big DC converter in every car then no luck
  - stetrain 3y ago
    So an AC outlet with a built in meter and payment terminal, that simply provides AC power to the car with an onboard DC converter, already exists. That's what basically every Level 2 EV charger is today. (Really it's an "EVSE" not a charger, it is doing no charging work) They have a couple of extra safety features (like a contractor and GFCI) and include the cable (in North America, in countries with the Type 2 connector you bring your own cable). These chargers go up to 19.2kW commonly in the US, although the charge rate can be limited by the installation (circuit size) or the car (onboard charger capacity).
  - stetrain 3y ago
    A helpful video about what's inside an AC EV "charger": https://www.youtube.com/watch?v=RMxB7zA-e4Y https://www.youtube.com/watch?v=RMxB7zA-e4Y Really the only difference with the fancier ones is they have a screen and payment terminal or NFC terminal for activating and paying. Like a gas pump, although most want you to use their app and membership to save (them) on credit card processing fees. DC fast chargers are a whole different story, where the AC to DC conversion happens external to the car.
  - supergeek 3y ago
    Gas pumps are larger transactions, so the credit card fees are less of a hit for the business. A level 2 AC charger is about $1 per hour of electricity, so you're taking huge credit card fees for shorter charges. Most of the apps have some sort of balance that lets you make one $10 transaction and then spend it on a lot of smaller charge sessions.
    - gcheong 3y ago
      That's an interesting wrinkle on what should be an otherwise tractable. Perhaps the government should subsidize the transaction fees in some way like they subsidize the oil companies.
      - NavinF 3y ago
        You must be using an unusual definition of subsidy. Gasoline is heavily taxed just about everywhere. Anyway shifting around the costs doesn't change the fact that paying ~30% in fees is very inefficient
frankus 3y ago
There's actually a clever way to reconfigure the inverter electronics and (induction) motor to essentially do "regenerative braking" off of a 3-phase supply (https://patents.google.com/patent/US5341075A/en https://patents.google.com/patent/US5341075A/en). I'm not sure if this is so widely used as to not be worth mentioning, or if there are hidden gotchas or patent encumbrances that keep it from being widely used.

vel0city 3y ago

Yeah but even adding a credit card terminal massively increases the complexity compared to the plain plug the author is talking about here. If you're going to have to include relays and ground fault equipment and payment systems you're 95% of the way to a "complicated" EVSE.

stetrain 3y ago

So the power meter dutifully ticks up the charge you have used while plugged in. Then what? How do you pay it? Do you have to go track down some person who may or may not be on duty to read the meter, hope they read it before you started, and pay them in quarters? Cars are designed to use AC. That's how all current Level 2 chargers work. They are basically dumb outlets plus a contractor, GFCI, and optionally a payment terminal. But beyond a certain level (around 20kW) the size and cost of putting a larger AC to DC converter in the car is prohibitive. At one point Tesla Superchargers were literally racks of the same AC to DC converters found in the car, but fed with 3-phase power, bussed together, and cooled all external to the car. There's no other way to implement a reliable 20-minute roadtrip charge.

lafar6503 3y ago
Oh come on, pay for use is a solved problem. Look at gas pumps. But if it's not feasible to have a big DC converter in every car then no luck
- stetrain 3y ago
  So an AC outlet with a built in meter and payment terminal, that simply provides AC power to the car with an onboard DC converter, already exists. That's what basically every Level 2 EV charger is today. (Really it's an "EVSE" not a charger, it is doing no charging work) They have a couple of extra safety features (like a contractor and GFCI) and include the cable (in North America, in countries with the Type 2 connector you bring your own cable). These chargers go up to 19.2kW commonly in the US, although the charge rate can be limited by the installation (circuit size) or the car (onboard charger capacity).
- stetrain 3y ago
  A helpful video about what's inside an AC EV "charger": https://www.youtube.com/watch?v=RMxB7zA-e4Y https://www.youtube.com/watch?v=RMxB7zA-e4Y Really the only difference with the fancier ones is they have a screen and payment terminal or NFC terminal for activating and paying. Like a gas pump, although most want you to use their app and membership to save (them) on credit card processing fees. DC fast chargers are a whole different story, where the AC to DC conversion happens external to the car.
- supergeek 3y ago
  Gas pumps are larger transactions, so the credit card fees are less of a hit for the business. A level 2 AC charger is about $1 per hour of electricity, so you're taking huge credit card fees for shorter charges. Most of the apps have some sort of balance that lets you make one $10 transaction and then spend it on a lot of smaller charge sessions.
  - gcheong 3y ago
    That's an interesting wrinkle on what should be an otherwise tractable. Perhaps the government should subsidize the transaction fees in some way like they subsidize the oil companies.
    - NavinF 3y ago
      You must be using an unusual definition of subsidy. Gasoline is heavily taxed just about everywhere. Anyway shifting around the costs doesn't change the fact that paying ~30% in fees is very inefficient

frankus 3y ago

There's actually a clever way to reconfigure the inverter electronics and (induction) motor to essentially do "regenerative braking" off of a 3-phase supply (https://patents.google.com/patent/US5341075A/en https://patents.google.com/patent/US5341075A/en). I'm not sure if this is so widely used as to not be worth mentioning, or if there are hidden gotchas or patent encumbrances that keep it from being widely used.