It pretty much took me getting bored enough to do it to finally make one, but here's my design:
In a 3x3 space,
Pneumatic Tube___________| Pneumatic Tube | Enderchest
Filter pulling from batbox___| Redstone Timer | Filter pulling from chest
Batbox___________________| Pneumatic Tube | Pneumatic Tube
Put something in the batbox. Set the timer to something like 28 seconds, or whatever, who cares, because you're gonna be grabbing the fresh one out of the Enderchest with a pouch.
This is the easiest low tech remote charger I've come up with/found, That specifically doesn't care how much charge your thing has left on it when you want to recharge it.
*edit* I put the _ so it's easier to read. Stupid thing won't let me type multiple spaces