Man, what a shit design. The problem is absolutely the connector/wiring. Since the wires are so short and need to be twisted, they're putting strain on the connector and are producing possible open circuits. I opened the GamePad up with it on, touched the wires, and the GamePad went to two bars, one bar, and dead within five seconds. I reseated the connector about six times before getting four bars, and I'll keep it like this for a while. Even though I shook the GamePad furiously to try to dislodge the connector and it held up (still on four bars), who knows if it'll stay properly connected for 5+ years. EDIT: Oh yeah, and there's the issue of the spotty charging light. If the flashing/turning on and off persists, fuck this battery. I'll be getting my money back and buying the Ninty one.
Anyway, time to see how long this damn battery lasts. I'll make a post later tonight...