Can you recommend any game or mod combination on Luanti? I have played a bit in some games, but always lost interest after half an hour.

Yes you need a specific battery tester.

Here is a Video explaining how to test batteries: How to Properly Test New and Used Li-Ion Batteries (Including Cool Testers)(15:12) by Andreas Spiess

At 6:14 he recommends a few testers. The more expensive ones list connection options via cable and Bluetooth.