The amount of time it takes to charge a vape pen depends on the type of battery and charger used. Generally speaking, most vape pens use lithium-ion batteries, which take around 2-4 hours to fully charge. However, some vape pens may use a different type of battery, such as a nickel-metal hydride battery, which can take up to 8 hours to charge. Additionally, the type of charger used can also affect the charging time, as some chargers are faster than others. It is important to note that overcharging a vape pen battery can reduce its lifespan, so it is best to charge it until it is full and then unplug it. Additionally, it is important to use the correct charger for your vape pen, as using the wrong charger can cause damage to the battery and other components.