A really original idea! I like the slightly quirky vibe of the whole thing!
To avoid a bit of frustration, I think it would be handy to keep a record of the charge you just attempted (and miserably failed at), so you don't end up repeating the same charges over and over! (And maybe indicate the syringe's direction—like with an arrow painted on it—to help you get your bearings in the interface a bit faster.)