Posted by a reviewer on Amazon

There does seem to be some confusion in these reviews though about the controller showing the percentage of charge

Posted by a reviewer on Amazon

When the panel is all hooked up and receiving power from the sun that percentage is the efficiency of the panel

Posted by a reviewer on Amazon

If it’s daytime in full sun it will read 100

Posted by a reviewer on Amazon

If it’s overcast or in the shade that number will go down

Posted by a reviewer on Amazon

The panel does tell you your battery charge as well but that only happens if the panel is either disconnected from the controller or if it is pitch black outside and the panel isn’t producing any power

Posted by a reviewer on Amazon

If you have a fully charged battery that you know is full and the panel is hooked up and reading 40 it just means that the panel is running at 40 efficiency due to a lack of direct sunlight

Posted by a reviewer on Amazon

Disconnect the panel from the controller and the controller will give you battery percentage

Posted by a reviewer on Amazon

Power production at spec level