Why a portable solar panel can not reach its declared power when use?

This should be the most typical feedback for a portable solar panel from customers after they beginning the use. 

For example, when you test a 100w portable solar panel under bright sunshine, you may only measure out 80w. Then when it is charging a portable power station, you may see only around 60w into it. Why there may be only half power when it is working?

Firstly, the standard test condition to get the max power of the portable solar panel is AM1.5, 1000W/m2, 25℃. This condition is hard to be realized under natural light. So that you will always get a lower wattage value than the declared max power of a portable solar panel. 

Then when the portable solar panel is used on the portable power station, the data into the battery for charging is the working power of the portable solar panel. Always the working power will be reduced due to the consumption when working on load. So that you may see the further less power.

Above power info is just for reference. You will find the data be always changed as per sunshine intension and the different working consumption situations on the loads. And this is never a product quality problem, but the working feature of all solar panels. If you have any confusion during the use, please just feel free to contact us.