Earlier this month, the team behind the battery-boosting "Reserve Strap" for the Apple Watch suggested it was possible to use the hidden 6-pin diagnostic port in the Apple Watch to charge the device, and today they've backed up their claims with a video demonstration.
In the video, an Apple Watch charging on a standard inductive charger is depicted next to one said to be charged through a power supply connected to the 6-pin port on the device. The watch being charged through the port charges slightly faster than the watch on an inductive charger, reaching a 95 percent charge at the same point the other watch reaches a 90 percent charge.
The team behind the Reserve Strap for the Apple Watch plans to use the port to create a band with a backup battery inside, allowing the Apple Watch to be charged while it's on the wrist. The product is still in the early stages of development, but it's available for pre-order for $250 from the company's website.
The Reserve Strap is not currently certified under Apple's recently released accessory program for the Apple Watch, which will allow manufacturers and accessory makers to create approved third-party bands for the device. Apple has outlined a specific set of rules for Apple Watch bands, preventing them from blocking any sensors on the device, but its guidelines do not mention bands that access the 6-pin port. For that reason, Apple's position on Reserve Strap's use of the 6-pin port is unclear.
Apple has not confirmed what purpose the 6-pin port serves, but speculation has suggested it is used by the company for diagnostic purposes. Apple may also be using the port internally for charging, as detailed in documents covering the function of its in-store Apple Watch displays.
It is not known if Apple has plans to expand the usage of the 6-pin port in the future, but TechCrunch has hypothesized that the port could eventually be used for "smart band" accessories to bring additional functionality to the Apple Watch.