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this post was submitted on 15 Sep 2023
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Possibly even more significant, those are some large cables and even larger contacts required. There's no way a 1MW disconnect is just a little plug you stick into your car.
In fact as an electrician I can't think of anything even near megawatt class that would be connected with a portable cord, or at a voltage that would be safe for consumers to handle.
Maybe someone in the mining industry or similar can chime in, but I currently run a pumping station that includes 3000HP motors (2.2MW). These are 4kV 3 phase units where each phase cable is as thick as your arm. All connections are bolted and taped to avoid corona discharge. Just dragging the cable to the car would be more than the average driver could handle.
I don't see a way to get these power levels into a car short of a standardized and semi-automated docking system. Or maybe go back to the idea of standard swappable batteries where the battery then is charged rapidly for the next customer.
The power lines in the cable are disconnected inside the charger by a contactor until communication with the car is confirmed established with a handshake, and then it connects power to the cable. If the communication with the car drops at any point, the contactor disconnects the power to the cable. It requires both effort and knowledge to bypass this design, it basically can't happen accidentally.
Also, the cables you mention are that large, because they're passively cooled, DC car chargers have watercooled cables so they can be much thinner without overheating. And at 4kV you're looking at significantly different insulation thickness as well, compared to the 400-800V that electric cars use.
Electric busses already have automated docking systems, the only problem I see is cost
https://assets.foleon.com/eu-central-1/de-uploads-7e3kk3/39195/17_syb21_content1.79205c469709.jpg
u wouldnt plug in and plug out the thing live in a charger, no ? the charging station should detect when the car is plugged then activates some form of disconnect or something, to allow a 1Mw power to flow lol ? also 1Mw is far fetched, and the 6 min charging time is absurd. 12 min at 500 Kw speed would be more plausible
That's 4,350 amps @230vac. The service fuse for my entire home is 80 or 100amp (single phase domestic dwelling Australia). The main breaker is 63amp.
Fast charging uses up to 1000 V DC, and the current limits of conductors are typically set by the temperature it reaches when conduction losses heat them up. This can be (and is) offset by liquid cooling, allowing current installations to deliver up to 650 A (Tesla supercharger v3).
With improvements, it's not far off 1 MW.
DC fast charging typically runs at 400 volts, with some cars doing 800. They also do it with highly specialized equipment and service lines you'd never see in a residential setting.
When charging at home, you have all night. A 50A circuit will go 0-100 on most cars in that time, and if you look at what most people actually drive you can generally get by on much less.
how much amperage does utilities allow for residential use ? imagine charging ur car at 50 amp and decide to turn the heater on, only to trigger the breaker and cause the house to go dark lol. also home charging is costly as heck. 80kwh each night, wth ? u probably need 75m² of solar to generate electricity for 5 hours, generating 75kwh, enough to fully charge ur car for free, but also u need 7*11kwh powerpacks to accomodate all this energy. seems costly as hell. unless also ur job offers supercharger parking, which would be more suitable
yea, fast charging is usually achieved using DC.