Ideally, you should use The.Powerbank until it is completely empty and then fully charge it until all 4 lights are on. Use a 5V/2A adapter.
It is important that when the The.Powerbank is not used for an extended period of time, it should be charged from time to time. We recommend doing this once every 3 to 6 months. This is because when a Li-ion battery is completely empty and not used for a long time, there is a chance that it will reverse polarity and the battery will be pushed out of the casing. The battery can then no longer be used.