Have been considering methods to power both the Movi and iPhone for longtime laps shots or just to charge while between shots, etc. Wondering if anyone can confirm if it's possible to power and/or charge both the Movi and iPhone simultaneously via a USB-C splitter like this one: https://amzn.to/2wINHib E.g.: External power supply or battery pack connected to USB-A #1; iPhone Lightning cable to USB-A #2; and USB-C to Movi.... or similar config.
Your BIG issue is finding a super-flexible and slim cable to connect thru the Movi into the iPhone with no impeding the Movi's gimbals.
EASY: For the iPhone, I currently use the AmazonBasics Apple Certified Retractable Lightning to USB Cable. It has a very thin and flexible cable. I rubber band the small, retracting "hub" on an aluminum camera plate screwed to the Movi Accessory Mount or I just hold it in the same palm as the grip.
FYI, for anyone interested. This does seem to work, but with caveats. While an external power supply can keep both devices juiced over the long term, it may not charge either or both internal batteries simultaneously while powered, if the incoming amperage from the external power supply is not high enough. Couple that with amp ceilings by all USB and/or Lightning devices / chargers involved, including the power throughput of the USB cables. Curious if anyone else has tested to compare results.