For people using real time indexing on a laptop, kind user "The Doctor" contributed a script to automatically start and stop indexing according to power status. The script can be found here: https://framagit.org/medoc92/recoll/-/blob/master/src/desktop/recoll_index_on_ac.sh

To use it, you need to copy it somewhere (e.g.: '/usr/bin', but any place will do), make it executable (chmod a+x recoll_index_on_ac.sh), and edit '~/.config/autostart/recollindex.desktop'

Change the following line:

to something like the following (depending where you copied the script):

You may also want to change '/usr/share/recoll/examples/recollindex.desktop', otherwise your change will be reverted the next time you toggle real time indexing through the GUI. And, yes, sorry about it, this change will be lost on the next Recoll update, so save a copy.