All right, I have just uploaded XChat build 14 to Extras-Devel. This build adds the following:

• Optification.
• Shift+Space will now invoke nickname completion.
• Lagometer disabled by default, as it was causing 500ms wakeups.
• When you enable lagometer, it will run on 1s wakeups now.
• DCC timeout check now runs every minute (was running every second).

Overally, XChat should be way lighter on the battery now. In order to test it fully, you will have to delete /home/user/.xchat2 directory!