Either the vapor production will drop off kinda like the last drag before a battery goes dead or you'll notice a faint burnt taste and a flavor change. Stop there and you can refill it. Take a few more drags until the burnt taste gets stronger and you can throw it in the garbage and get a new one. When you get juice to refill a good policy is when you start a freshly charged battery put a filled carto on it. Full carto always outlasts a battery charge. They last a looong time if you don't run them dry. I keep enough bats and cartos so I can just top them off at night and they charge while I sleep. Some don't think it's a good idea to charge them unatended but I've never had a problem. If it bothers you just charge them in the garage in a coffee can or there are special lithium safety charging bags you can buy. This is just the way I do it. Others do it differently and may provide more info. Hope it helps.
Man, im having a really hard time deciding which smooth flavor i like most.
Nother newb question, how do i know when a cart is done?

