Quick one, hopefully.
For powering my Panasonic cameras on shoots I’ve been using dummy batteries with USB PD adaptors for the tripod cameras. These have been working OK but I recently found out this setup is actually slightly underpowered and it made me a little paranoid about stability.
For USB power directly into camera Panasonic say you need 9V @ 3A (27W) and this seems to be true for the dummy battery path as well. With my normal Anker power banks (9V @ 2.2A) although video recording is fine, if you try and do a burst with mechnical shutter (tested G9, GH5 II) the camera will shut down after a handful of exposures. When running from a 3A wall supply the camera can maintain a burst.
In Anker land, requiring 3A means moving up to their “65W” (45W on USB-C) output supplies designed for laptops which cost more and aren’t available in my prefered 10,000mah size.
The GH5 II and S5 II support USB PD directly into the camera. Both cameras need a battery in the camera to power-up, so it’s hard to test the behaviour of just the USB input.
However, with the S5 II I did a long running video test using the 2.2A Anker. At the start of the test the internal battery was showing four bars and after just under three hours of recording (256GB of data) it still had four bars and the power bank was mostly drained.
So I suspect the constant draw of the camera is much less than 27W but there may be short bursts somewhat closer to that level, and having the battery in the camera helps handle that. I can’t accurately tell how much power was taken from the internal battery, but the numbers suggest an average draw over USB of under 10W.
For the G9 this battery supported power bank approach doesn’t work as the USB power input on that camera is mostly useless and the internal battery will run down, albeit at a reduced rate. Using the dummy battery with the 2.2A source and another power-bank into the USB port it still shut down on a burst. So for that one it means with internal batteries or a 3A power bank.