The indicator lights from a WakaWaka Power+ should work as following:
The single light on top of the WWP+:
This light blinks when the WWP+ is charging via the solar panel. You can hold your WWP+ with its solar panel towards the sun or hold it under a strong lamp and check if the light is blinking.
The 4 lights on top of the WWP+:
These lights indicate the battery status. 4 Green LED’s = 100%, 3 green LED’s = 75%, 2 green LED’s = 50%, 1 green LED = (<)25%. If the battery status shows only one light, it could be that your WWP+ doesn’t have enough power to charge your phone. However you can still use the light perfectly!
The blue light next to the USB port:
This blue indicator light will light up when you charge a phone or another device via the USB port. Open up your WWP+ to see this light.