Here's Usher charging his iPhone at Art Basel in Miami ... using a battery pack jammed inside of a woman's vagina.

Usher paid $20 in exchange for 10 minutes of juice Wednesday night. A crowd of distinguished art enthusiasts stood by and watched the entire thing.

The woman wanted to show how humans have become dependent on technology and she felt a super-charged vagina would help make her point. We totally get it.

Don't worry, the vagina was equipped with a second battery pack ... in case anyone had a Droid.

Fun Fact: The woman tells TMZ she could take two phones at the same time.