Slide off the Apple Watch's bottom band, peek into the connection slot, and you'll notice something interesting. It's a hidden port that Apple doesn't acknowledge on its website or in any documentation for the smartwatch. That would suggest it's not something for consumers to mess around with and exists for Apple's own internal use. But one accessory maker claims this six-pin port can in fact be used to charge the device — and it'll apparently charge at a faster rate than plopping Apple Watch onto its inductive charger. Without offering any direct evidence to back the claim, a company behind one upcoming battery strap, the Reserve Strap, says its engineers "have been able to independently confirm that the six-pin diagnostic port underneath the Apple Watch case can be used for charging."
Prior to this apparent discovery, the Reserve Strap's initial design called for it to charge Apple Watch through inductive charging, which would mean serious tradeoffs for users. "By utilizing this port instead of wirelessly charging, we’ve been able to achieve a higher charge capacity and quicker, more efficient charging times while also improving durability and eliminating any interference with Apple Watch functionality including taptic feedback and heartrate sensors."
The port is covered by a metal door, and Apple obviously doesn't include any tool for opening it in the box. Reserve Strap says it will provide this when the $249 battery band— yes, that's the actual price — ships this fall. But even if Apple Watch can be charged this way right now, Apple could disable the port or cripple it for outside parties through a future Watch OS firmware update. Then, all possibilities for docks and accessories that plug into the port would immediately vanish. If Apple won't be using this port for its own accessories, it's doubtful the company will let anyone else cash in.