My vamo v6 came with two 18350 batteries 900mah, and today arrived two 18650 5000mah batteries that I got for 4 quid or so off the bay, what a difference they make! the small batteries would last hmm, a hr and half of vaping before needing charging (using one at a time in the vamo v6), and this big battery iv used it for 4 hours its not even dropped down 1 bar on the battery meter on my vamo! amazing.
Also iv gotten used to top filling my kayfun 3.1 now, only loose hmm one drop or so when I fill up now, I tend to not fill it as much and it doesn't leak, does mean that I have to fill it every hour though, though that's better than my old protank 2 mini that I had to fill every 15 mins lol.