The part of a vape that controls the power and the battery life is the Cell or battery used inside the device. This can come built in with a USB port on the device to charge it or separate batteries that need to be removed and charged in an external battery charger.
There are positives and negatives to both but as a rule. if you have a slightly more powerful external battery vape that is running over 25 watts plus or has more than one battery in it, for safety and for best performance reasons we recommend you use an external charger from Xtar On most devices there is a usb port of some sort but it is best to save that for software upgrades if needed and or emergency charging only.
If you wish to only charge with a USB Lead only a built in battery device is recommended. Please take note of the charge rate your device needs as some require more or less Amps. If unsure then please use a maximum of 1amp plug as some are fast charge capable it is essential to use the correct one for the safety of you and your device.