[tomsem]

There are a couple of things you could check:
- is it indexing anything: from home screen, search for '.' (period). If it is indexing anything, you'll see an item to that effect. Tap on that to see what it is working on. Sometimes there is a corrupt item and indexing cannot complete, and drains battery trying. Solution is to remove any item it is stuck on and get a fresh copy.
- check the size of 'My Clippings' (open it and see how many locations there are). If you make a lot of highlights bookmarks etc. it gets larger and it takes longer to reindex it each time something is added, draining the battery etc. Solution is to delete My Clippings so it can start fresh (after backing it up to your computer if desired).

I don't think the size of individual items has any effect on battery drain (once initial indexing completes).