I tried to search" battery " as my key word . And most all the threads have nothing to do with batteries
The best way I have found to search is not the box at top in middle but go to the blue bar just under that and select search. Then after you type in say "battery" select the drop down box and change to in headings only. Plus that search area lets you be more specific. Has worked better for me anyway.
You are better off using advance search, and search only titles. If you find a thread you like, and might want to find in the future, edit tags, with what you like about thread.