That's like discovering perpetual motion...

It's not going to happen.

Some of the best inverters are only about 75% efficient, plus losing
efficiency though a battery charger. You'll actually be draining the
batteries ... at a quick rate.

dh@. wrote:
Someone told me it's possible to charge an inverter
system's batteries using a battery charger plugged
into the inverter that's being run by the batteries
you want to charge. Is there any truth to that, and
if so, how does it work?