Swapping requires a lot more moving parts and an additional enclosure to house the battery, and the batteries need to be much more rugged, and now you need two of them.
But a cable is a fair question.. you'd think it could plug itself in...
Maybe that's a hint at the robots actual capabilities at this point... or, they didn't want to bet on the unpredictability of environments: what if there's something in the way of the cable, though something could also be in the way of the inductive charger
I believe Elon has said before re:Tesla factory that plugging in cords is one of the hardest things to automate.
I'd appreciate a link. But "we don't trust our robot to be able to locate a power outlet and plug its own charging cord in there" sure is a low confidence play.
There are practical advantages to being able to charge wirelessly, sure. But if they're doing that because of AI limitations? Bad sign.
Tesla showed a prototype of a "snake"/"tentacle" charger that would find its own way to the Tesla's charging port a long time ago. Gotta be 5+ years by now. To my knowledge it has never become a real product or certainly not mainstream among Tesla owners. I believe this gives some credence to Tesla struggling to build robots that can plug a cord in, even in cases where the robot is the cable.
They're building cars, so it's more like ATX 24pin style cables, but this is generally true. Cables, wires, ropes type of objects are like cardboard thin robots with hundred joints in series and under someone else's control, so it's hard for robots to deal with. If you think about it, people hate cables too. We easily get tangled in headphone cables when they're wired, and we fail to coil or untangle Ethernet cables properly all the time.
EV charger style of short, thick cables should not be THAT hard, though. The more likely problem here is that they just can't handle the task of securing and inserting the head of the cable against resistance.
Surely if the cable design was under your control, you could make it a lot easier for an automated system to plug in. Have it be sort of like a TRS jack, but cone-shaped. Then you don't have to get it perfectly aligned, it will align itself when inserted. Put a magnet in the tip to hold it in place, or some sort of electrically actuated lock that the robot can unlock when it wants to unplug the cable
Yeah, immediately after I wrote that I thought now you need a rugged socket, and to mount the cable somewhere on a wall.. and where to even place it on the body that it's easy for it to plug in.. the belly button?
There is empty space in the feet anyway for a coil and a wire..
Forget sockets. My $15 fitness band uses a magnetically-assisted pogo-pin type thing. Works great. Just blow that up to 5x to get nice fat conductors. All you need to do is get it close and it plugs itself in. Knock it off perpendicularly to disconnect.
My Roomba could do it in 2007. Then, in 2015, Tesla tried and gave up.