I honestly think that somewhere in the description of this product, it should have been made clear that you need an external battery charger. Every other mod that I’ve had has been able to charge via USB. So naturally I assumed this one could as well, which is the exact reason I didn’t buy a new port charger in the first place. However, it should also be understood that charging 18650 batteries with a USB, such as the ones the T-Priv 3 takes, is very dangerous, with chances of batteries catching fire or even exploding. In all honesty, buy a quality 4 port battery charger, very worth it and saves a lot of time, as well as much safer.