Get yourself a Silver Bullet, an 18650 2400mah batt & charger and vape non-stop for better than 24hrs. I just did that and this bat is still going strong. Consistent as hell all the way thru. I'm going to bed now and I'm putting it back on the charger.
I may never find out just how long this batt lasts! 8-o
PS - I love my Silver Bullet and have seen literally zero complaints about it. That said, there are a bunch of mods that take an 18650. Find the one that fits you best.
GL!