I never counted puffs. I get about 25 minutes pretty much chaining which is about how long it takes to charge one. A better question would be how long the PCC lasts. I have two and alternate and, so far, neither have died in a full day (around 15 hours.) If you have a car charger, just charge the PCC (optional with battery charging in it or not) while enroute... that way its always going to be charged but, IMHO, its really not necessary.... just if you're worried about it until you learn how it acts. Also, only if worried,
buy a spare battery along with the two that come in the kit.
Edit: Ugh, I'm sorry I just read your header again... forgot or never realized you were asking about
tanks. I've never really checked that. I load up six in the morning and they last me all day with one or two to spare. Just get a another box of 5 for about 3 bucks and you'll have eight... that, for sure, gets you
through the day.