waybar upower module
When I was running Waybar's upower module it was giving me segmentation fault (core dumped) error. The configuration was correct so I did not know why it was happenning.
After searching the web about it. I found out that, installing the git version fixes the issue. I tried it and yes, it fixed it for me. So install the git version. The waybar-git AUR package is depreceted. So you may have to compile it on your own.