• BussyCat@lemmy.world
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    3 months ago

    It doesn’t need to be, high voltage transmission lines can run 1000s of MW then you can use a transformer to step the voltage to what you need and then use a rectifier bridge to convert to DC.

    The problem I see is the effect of trying to turn on and off 1MW power from a grid could cause problems so the battery could work a bit as an expansion tank to smooth out grid power, so that you always charge it at 100KW and if you need to increase supply you can slowly increase your power draw without shocking the grid.

    At the end of the day I personally think 1MW charging is overkill and a 10 minute charge time is a perfectly reasonable goal

    • LucidiaDiamond@lemm.ee
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      3 months ago

      Why not use a large capacitor as a buffer. Would give peak power at the beginning of the charging cycle which is what you want anyway for quick turnaround.

    • ExLisper@lemmy.curiana.net
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      3 months ago

      I see couple other problems:

      • you need to put some of the chargers in the middle of nowhere (next to a highway, hundredths of km from big cities. in Spain for example there’s a lot of depopulated areas). Building all the infrastructure to get the power there will be very expensive
      • even in cities changing the grid like that can be very difficult. My office wanted to put 10 slow (20kW) chargers in the office and it took a year for the power company to make the necessary changes.
      • at a gas station it’s hard to break the gasoline supply. Individual pumps can break but the supply is very robust. If anything at the 1MW charger breaks (lines, transformer, converter) the entire things goes out of service and will take hours/days to fix. Building those charges to be as reliable as gas stations will be difficult and expensive.

      The charging times are not about how long do you have to wait while your car is charging but how many cars can you charge at peak hours. Last Easter in Spain there were huge lines to the charges because everyone was driving at the same time and there were simply not enough chargers. 5 min vs 10 min charging means the line is moving twice as fast.

      • BussyCat@lemmy.world
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        3 months ago

        For low travel areas slower charging and batteries make a lot more sense as the investment in ultra fast charging is not viable and I don’t see that changing

        I think regulatory inertia Is always going to be a problem but if we are regularly adding charging stations it will get faster as power companies have an incentive to build them and you get staff trained up on them

        Gas stations can still have single point failures for example if their underground tank gets contaminated or damaged and they don’t have a back up and electric doesn’t need to have single point failures you can run them in parallel with breakers able to isolate portions of the system and have redundant transformers

        EV works best if most people charge at home/work and people only charge in public if they don’t have the ability to do it at home or they are on a long drive. So you don’t need to meet the same cars per hour as gas stations.

        I don’t see a world where fast charging is as cheap as slower charging just due to increased losses and more expensive equipment so I believe having 10 500kw chargers would be a better investment than 6 1MW chargers even though technically the MW chargers have a larger throughput they are more expensive to produce/run and have more issues if for example 8 people arrive at once