The weight of the battery needed to charge a Tesla at anything like a 'fast' rate would be huge ... there's no efficient way of then propelling such a heavy battery along without then needing even more heavy batteries or a big ICE engine. So nope.

I think this is meant to complement the (as yet unreleased) Tesla can-park-itself-in-your-garage feature.

I bet there could be creative situations where it could work. Imagine a rig that joins to an electric overhead line (like a light rail). The rig could move at the speed limit around the ring-loop of a city's interstate. Cars can pull alongside it to charge. If it had enough arms, and was narrow enough you could charge quite a few cars. If its then charging from the grid it needn't actually be propelling a battery at all.

Or in a situation where moving the battery already happens. Maybe where a whole fleet of trucks have purchased into a booster pack scheme. The booster packs fall on and off at various cities along a long route. Kind of like jettisoning a space shuttle's boosters. On either side of the city you have 50 packs charging. Radio that you need more juice and as you hit the city limits a booster latches on, you trail it through the city charging your main pack back up, and drop it off on the other side of the city where it charges and waits for someone going the other way. The truck never stops, it just keeps going and gets 'boosted' by a self-driving battery trailer every time it's within 100 miles of a city.

Or allow you charge-up without really doing anything. Stay inside your car and read at the supercharger station!

Or, cars become a shared resource and you just call up basically a driverless Uber when you need it. That's the future I want to see in e.g. areas where mass-transit is blocked politically (e.g. BART from SF to SJ) or where the population density is such where it doesn't make sense.

Looks like Elon plans on competing with Uber.

http://qz.com/473803/tesla-ceo-elon-musk-on-potential-uber-p...

Imagine your robo-tentacle in drab safety black-and-yellow, have a hundred of them waving in the dark waiting for their JohnnyCabs to come in for a charge between fares...

The tyranny of the self driving self driving car refueling bot.

In stunt mode you could just gang several Model S batteries together (which would fit in the back of a pickup). I guess the idea isn't very practical though.

They should have made the charge port in the back center of the car. Then while driving along a charging vehicle with a snake on the front would drive up behind and charge you up! Now that I would pay to see. You could even make it a detachable accessory on all electric cars so any car could give any other car a mid-flight boost. The future is bright and potentially very funny.

Very cool tech indeed.

A battery swap while on the move might be more efficient/faster then a charge on the move. (But it would be nice if the next-gen solar panels installed on a car would be efficient enough to provide enough power for a car drive)

  (But it would be nice if the next-gen solar panels 
  installed on a car would be efficient enough to provide 
  enough power for a car drive)

You only get about 1.5KW of light per square metre, on average. A car has maybe 4-8 square metres of usable solar panel space, so guess you could get 3-6KW of power using superexpensive cutting-edge 3-junction solar panels that manage 50% efficiency.

Model S has a 310KW motor. Assume you only run it at 10% of rated power when cruising, and that's 31KW of power draw. More than that, of course, since the motor controller won't be perfectly efficient.

No way you can run a consumer vehicle on solar panels built into the body.

It can work as a range extender, though, especially if factoring in charging while you stop for a bite to eat, shop, visit the office, etc. In addition, if you're an occasional driver, it can be charged and ready to go if you simply park it in a sunny spot.

I'd pay extra for such solar panels in the roof.

You mean like this?

https://www.youtube.com/watch?v=H5V0vL3nnHY

And I doubt solar panels would ever be used for charging the whole car in a very significant way, even if they had 80% efficiency.

Somewhat like this but while on the move

In the future roads would probably contain wireless charging within them with solar panels alongside them.