I’ve worked using Arch Linux for a while without a battery monitor app, and finally decided to cure myself of this issue today. (I’ve dealt with this problem before.)
I chose KThinkBat as my kicker applet of choice. As expected it didn’t work with my Compaq Presario 1720 out of the box. Same ACPI culprits as usual. For version 0.1.5 of KThinkBat, my problems were fixed with this patch.