I am fairly new to this having just started vaping in April. But I feel like a pro since I have to have spent well over a grand. The 134 mini was my first real mod after the spinners and such. I got it thinking I'd run it with the regular Efest 18350 batteries. Well, those didn't last more than 30 minutes. Then i read where the the 18500 Efest Purples were safer. Bought those. Got maybe an hour max. Took it back to my local B&M dealer, where we proceeded over a couple of weeks of trying different batteries as well as units. Finally wound up running AW IMR 18490 batteries from RTD Vapor in unit number three. I get a little more time but not much. From my experience, the 134 mini just runs through batteries like a fiend. Then I bought an eVic Supreme and finally a ProVari Mini, which is what I should have bought in the first place. With it and the 18490 AW battery I can go through a couple of tanks using the Nautilus Mini.