For $30 you can get a Milwaukee USB adapter that fits on top of any M18 battery so it can be used in any brand of vest. You'll likely need a USB extension cord, though as keeping a battery of that size in a vest pocket can be a bit cumbersome.

“In a time of deceit telling the truth is a revolutionary act.”
― George Orwell

It's not over when you lose. It's over when you quit.