Without getting too in depth, I'll try to explain;
To change battery pictures, you must open the framework-res.apk file in 7zip and replace the existing .png files with the ones you want (while i'ts still "compressed" aka packaged, DO NOT UNZIP IT. Sounds easy, but it get's complicated;
Accurate battery mod means that the XML has been edited to show an image at more specific battery levels (1,2,3,4,5...) So, if what ever theme/rom you're trying to change already has this mod in it then you just have to make sure that the theme you're pulling the new clock images from also has the mod. This is obvious because there are more images than the stock version (it went by 10's and 15's)
EDIT: Just going to leave this random bit of info here lol..