Is it possible to charge a battery from a live with without creating a second ground?

Question

This came about out of a conversation with a friend and we were wondering if it was theoretically possible to power a device with a hot wire and have that device's neutral/ground be attached back to the same hot wire? Assuming the hot wire is eventually grounded itself.

We just want free power.

Would it work in space?

    +--> fusion power plant +---+---^-----------> earth ground
                      |       |
                      |       |
    +-----------------|-------|--------------+
    |Device           |       |              |
    |-----------------|-------|--------------|
    |                 |       +------+       |
    |        +--------+--+           |       |
    |        v           v           |       |
    |   processor<------+global storage device|
    |   sensors                      |       |
    |        +                       |       |
    |        +-----------------------+       |
    |                                        |
    +----------------------------------------+

Answer 1

No. Electricity travels in loops. If you don't have a loop, it will just sit there.

In mains electricity (which I assumed we're talking about here since that's what we do in a home improvement stack), if you somehow manage to ground any of that, you'll get a big bang poof until something burns, blows, or trips.

Now that I see your edit, I see more where you're coming from. The first thing is that current travels in loops, it needs to return to source not ground. Ground is not a return for human generated power: neutral is return.

In mains power, we do bond neutral to ground. But in mains power at the level you would ever charge a battery, you must always wire the neutral, you cannot use a wired ground or the earth for return.

If you are the power company, then yes, you can do that for distribution between far-swept buildings; it's done in the outback of Australia and in developing countries. However all these use very, very high voltage and low current. For a reason.

In low voltage power, you can do almost whatever you want as long as voltage is kept below 30V and wattage below 55VA. But it won't work very well for the same reason: Dirt is a terrible conductor. That's why we go to all the trouble to dig up copper and smelt aluminum.