How to disable charging on a USB-C port on MacBook Pro (M2 Pro)?

fxffs wrote:

How can I disable (at least temporarily) the charging via the USB-C port?

The simple answer is that you can't. When the MBP senses an external charge source on the USB-C port (e.g. your batteries), it draws from the external source to charge itself. The MBP was designed to work this way.

The only way the MBP powers connected devices is if they are bus powered such as a flash drive or external SSD or HDD or if it's an iOS device.

Although it may seem that some unidentified software setting could "reverse" the charging action so you could charge a connected battery, I have never seen any such setting on any system.

fxffs wrote:

This is a DJI Osmo Action Multifunctional Battery Case with three batteries. So no, I can't do anything with it on that side.

What you are encountering is seemingly the way that this is supposed to work:

https://dl.djicdn.com/downloads/DJI_Osmo_%20Action_%203/AC/0916/DJI_Osmo_Action_3_Multifunctional_Battery_Case_Product_Information_v1.0.pdf

For further assistance with this battery, check with DJI.

Plug the video camera's USB-C charging cable into the Mac's power brick.

fxffs wrote:

Please don't point me to the manual. I asked a specific question, but I have no answer so far. The USB host can decide how it wants to operate and what it wants to do. It should be possible to change programmatically. Would you like me to point you to the specifications?

To remind you, the question is: how (if it is possible in macOS) to disable power charging over the USB-C ports?

You have purchased two devices, and both are working exactly as intended.

Apple doesn’t provide a documented user APIs for accessing and controlling USB PD. If an API for this even exists above the level of Apple firmware, which I doubt.

The charger is deciding what to do here, and which means your question should be addressed by the charger vendor as that device is switching its operations, or potentially with the creation of a custom USB-C dongle that messes with the USB PD signals (not easy) to fool the charger.

Here are the DJI forums: https://forum.dji.com

Which camera is this? Are the batteries inside the camera, or are they removed for charging?

You can’t, get an AC charger with an usb-c connector and charge the batts using that