Despite it is a power bank, it can also be recharged by solar panel under sunshine except AC power adapter. The power of solar panel on power bank is from 1W to 2W. So the current of solar panel charging is around 180mA to 360mA. For charging 6000mah battery fully inside solar power bank, it may need 20-24h.
But how can we charge the solar power bank during camping or mountaining?
Make sure solar panel side are not be covered by dust or other stuff.
Expose the solar panel side to sunshine. If sunshine is not strong enough, it needs more time for charging
If the solar panel under sunshine is charging battery, the green LED would be blink.
When it is fully charged, you can start to use it as a camping lamp or smart phone charger.