I get about 4-5 good solid hits from my HP LV Evo before the ultra gets really hot, and by then I figure I have strained the battery, so I usually just empty the battery out and let it cool, and load a fresh one, and keep going. It's still not much more than I was getting from the 6v T1 (4 hits made it really hot), but considering the size difference, I would say that still isn't bad. For a few quick puffs, in the smallest, most pocket friendly vape I have to date, I'd say that isn't too shabby. Now if you are looking for long term vaping, either keep a bunch of batteries on hand, or go to the next size up (t1 body 17670 battery) might get a few more pulls from that one before the battery gets too spent. Honestly I have not spent enough time getting to know the HP LV Evo/T1 set up, so I can't say for sure how much more life you would get. I do know that the Ultra/HP LV Evo combo gets me medicated enough on one battery, that if I were out somewhere, and just needed a hit or two for maintenance, this would do it for me no problem. However, I have not put it to the full test yet, as I usually just carry my Pax around when I go places, so I have not truly tested the Ultra/HP LV Evo in the real world, just here at my desk, or out in front of the house standing with the smokers.