Logs are located in /var/log/ for the most part. A few things put error logs elsewhere, but most of them are here.
Patching kbattery or k8temp *might* not be the solution. I recommend you search the LKML (Linux Kernel Mailing List) which you can locate using Google, and search it for ACPI related threads with keywords such as your computer make/model, motherboard, 'ACPI', and check out the KDE website for similar issues.
The ACPI system under Linux is a work in progress -- most of it works on some systems, but not all of it works on all systems, especially without system-specific configuration.