Ok - Thanks all, I was just looking for a recommendation for the longest lasting 18650 using 13 watts and a 1.6ohm coil. I have never actually used a protected battery and probably shouldn't have linked to them as they probably wouldn't fit as puffon mentions. What I didn't want was a long technical discussion about battery chemistry and safety, I just wanted some actual users of actual batteries in their mods to let me know which 18650 seems to last the longest at around 13 watts. Sorry for any confusion.
Just read that after I posted my comment, please ignore what I wrote about protected batteries.
My understanding of the guide I've linked earlier: for 13 watts you need a good brand, high mah and 10-15amp battery. Sounds about right guys?