One word: clearos.
An inherently flawed delivery system.
It's not your battery, it's the delivery device. A battery is just a battery. It provides power to the delivery system. Your delivery system seems to be the weakest link. I'm not about to tell you what you "should" use. What works for me may not work for you. But all of your problems with clearos? I've had them, too.
Finally put them down for good. The only reason I keep clearos around is the rare emergency when I'm out of cartos.
Some people hate cartos and say they can taste the polyfill. I don't, so I prefer carto tanks.
Some people hate clearomizers and say it alters the juice flavor, giving it a burnt, metallic, plastic-y taste. Dry hits, gunky hits, etc. I fall into that category.
More than anything, I wanted consistency. With each and every hit. I didn't want to have to slosh a tank around to make sure the wicks were saturated. If a clearo tank got to less than half, I'd get a burnt or dry hit with almost every puff, unless I sloshed it around or refilled the tank.
Nothing made me more mad than clearos. When I finally learned how to properly prime and refill carto tanks (without end caps popping off and juice spilling everywhere, without underpriming, etc), it was like the clouds parted and a beam of light shined down upon me from heaven. Flavor as delicious as direct-dripping, and none of the hassles, burnt/gunky/dry hits from clearos.
Also, I've had some cartos last me over a month. With clearos, depending on usage, I got about two weeks before needing to replace the heads.
But hey, to each their own. That's the beauty of vaping, there are options for everyone.