did it say "might take UP to 8 hrs" ?
you should not charge UN attended (mostly sleeping)
once a Li-Ion battery is full charged, continuing to charge can harm it internally
I only use a wall charger, just because IF there is a problem I don't risk my computer
I don't allow my batteries to drain very low and recharge time usually about 40min - 90 min
have you ever read the numbers on your charger? (wall adp and USB cable)
one line will say OUTPUT: 500mA or 450mA or 420mA -- the bigger number will charge faster
use it hard, charge it up and vape some more ...![]()
I honestly didn't think it was a problem because it recommended charging it for the first time for 8 hours. The exact wording in the included pamphlet is: Recommended charge time is 8 hours at first time use.
Picture of pamphlet:

The charger says: Model: USB-S001, Input: DC5V, Output: DC4.2V - 420mA
MTLBYAKY
Jana~