Call my cranky, but I've been a bit annoyed that this thread w/this particular title has been bubbling up (when I use http://www.mynissanleaf.com/search.php?search_id=active_topics), due to replies.
For some reason, I instinctively miss/ignore the word "battery" which to me, gives the impression that Intelligent Key is problematic or has issues, which is not true. But even w/"battery", I've never had any "battery issues" w/the IK. They last about 2 years, which is what the manual says. I recall replacing them on my 2 year leased car near the end.
I'm fairly sure I had to replace them on the 2-year lease return I bought. Big deal. I don't use crap coin cell batteries from Harbor Freight. I don't use ones that too thick (e.g. CR2032). I don't get mine from sketchy sources (e.g. wouldn't surprise me if some of the really cheap "name brand" coin cells on Amazon are counterfeit). Mitsubishi batteries from Daiso (http://www.mynissanleaf.com/viewtopic.php?f=30&t=20218&p=431071&hilit=daiso#p431071) seem fine. 2 packs of those are $1.50.
I've also had Toyota's version (Smart Key System) in my 06 Prius since 06. That fob comes with and takes CR2032. Fob batteries last maybe 1-2 years longer in the Prius' SKS than in Nissan's IK. Have I ever been driven "nuts" by this? Nope.
Maybe this thread can just be locked? OP already started another thread on this before (http://www.mynissanleaf.com/viewtopic.php?t=20163) even though there have been other fob battery threads. And, I think we can conclude that getting coin cells from HF is a mistake.