Comment by dpark
3 days ago
I have a robot vacuum that manages to do automated direct contact charging just fine. I don’t understand why wireless would be any easier. It seems more complex and less safe than a direct wired connection.
I also have a lot of trouble believing in the scenario of a neighborhood that has an automated charging station for EVs but no grid. That seems like very misplaced priorities.
Robo vacuum charging is almost inherently safe. They probably charge at something like 12V/2A. Voltage too low to penetrate skin, wattage too low to cause serious injury unless you’re really trying.
You can kind of just leave them exposed and live.
None of that applies to a 220V, 50A (or whatever amperage) charging. That can absolutely kill somebody; jet fuel may not melt steel beams, but 11,000W sure will.
You’d end up needing some kind of recess probably, and then getting cars to connect to it like planes refueling mid-flight is a nightmare. You could try some sort of USB-C like signaling before power is sent, but people are never going to enjoy “exposed 220V contacts that may or may not be live depending on if things malfunctioned”.
The point wasn’t that my robot vacuum is handling large current but that “moving device connects to power” is a solved problem. A car capable of driving itself onto this pad could as easily drive itself to a spot to plug in. Extendo-arm from the car could easily slot into an outlet in the floor. Or vice versa. Or a wall or pole.
Planes refueling mid flight is hardly an apt metaphor given the charging station isn’t moving at all and the car can move as slowly as needed.
This seems like one of those “reality has a surprising amount of detail” situations.
Surely getting something to autonomously without fail extend an arm and plug in for the lifespan of these vehicles vs just park in this allocated spot you would park in anyway is an obvious tradeoff.
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> A car capable of driving itself onto this pad could as easily drive itself to a spot to plug in. Extendo-arm from the car could easily slot into an outlet in the floor.
Those two things really aren't comparably difficult. Eg in the dumbest case for pads, you could make the pads slightly smaller than axle diameter (to prevent dead shorts) and have the car randomly jostle around the space until it detects current flow. I've seen some amateur systems that work vaguely like this. Some signal that charging is nearby, and then a semi-random search to find exposed contacts.
That's not going to cut it on a recessed outlet. Your odds of hitting it randomly are tiny, and it will probably the damage the port with enough repetitions of ramming it into the floor.
> Planes refueling mid flight is hardly an apt metaphor given the charging station isn’t moving at all and the car can move as slowly as needed.
Change your reference point to the plane carrying the fuel and they get an awful lot closer. The planes are moving a lot relative to the ground, they're moving very little relative to each other. I'm not sure if you've watched them doing it, but relative to each other it's actually a very slow process.
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