[Aaron2222]

Amphetamine[0] lets you prevent sleep on lid close. I presume it lets you do so without AC power (but I might be wrong on that), but one of the techniques they use to do that (setting the IOKit key that indicates the system is currently in clamshell mode) definitely does work without AC power. I made a command line utility[1] for myself a while back that does that if you're interested. It works fairly well, but the clamshell state tends to reset upon gaining/losing AC power. That's fine if the lid is open at the time (as the utility just applies the change again), but if the lid is closed, the system sleeps until the lid is opened again (at which point, it reapplies the change and you can close the lid again).

[0]: https://apps.apple.com/us/app/amphetamine/id937984704?mt=12 [1]: https://github.com/Aaron-Rumpler/CDM