Power your Panasonic GH3 GH4 GH5 on USB? YES!!! Micro 4/3 power HACK!
USB powers everything, even those things that USB doesn't power. I tested this little QuickCharge 3.0 USB power adapter with a battery dongle for my GH4 to record for hours and it worked great.
https://amzn.to/40YU2SB
Let me show you how this comes together - especially since the Panasonic GH3 GH4 and GH5 don't feature USB powering natively.