Just changed mine anyway and put the other on charge and I'm getting more of a crackle and better vape so at least I now know what to look for.
Carl after talking to Durks about all your vaping tools I'd of thought they would walk over to the charger and charge themselves for you.
I think it cuts off at about 3.3v (poss 3.2 - 3.4). This is an "under load" voltage so even if it reads 3.5v, it may detect a lower voltage under load.
Correct!