When I got the Power Bank hung on a solar panel, I was happy at first, that even with little sun begin charging lights flashing. Here was after 3-4 hours, the display on "battery full", and all four LEDs have shown steady light. However, you now so Invite a Device, then after a few minutes of juice out, and when the last LED device, which indeed means that the battery is empty flashes. For me, this behavior of the Power Bank that it does not measure, comes in how much power but only time measures how long it hangs on the current and then blindly "full" displays. This is confirmed by the way even in that case allegedly fully charged by solar battery, the battery not charging when you hang him on a power supply. Thus, these "top-up" games with solar modules is limited at full sun is possible.