Posted by a reviewer on Amazon

Overcast it wont charge and any brief moments of light may drain your phone as it buzzes on and off as it tries to charge

Posted by a reviewer on Amazon

Also having that other battery means i dont have to leave my phone in the sun to charge it most smart phones wont accept a charge if their battery gets too hot

Posted by a reviewer on Amazon

Tried in the backyard very sensitive to lighting conditions as expected but also pretty good output even when not perfectly aligned to sun position

Posted by a reviewer on Amazon

Must be in direct sunlight which makes sense its not like a calculator that will work with indoor lighting

Posted by a reviewer on Amazon

It was able to charge a phone while it played pandora

Posted by a reviewer on Amazon

Bought this for camp and hiking and ended up useing it in the back yard also

Posted by a reviewer on Amazon

Dont expect a charge rate as fast as if you plugged your device into the wall but in direct sunlight it charged my ipad at a rate of 5 per hour if i left it alone and kept it at a steady percentage didnt lose or gain charge listening to music and checking facebook

Posted by a reviewer on Amazon

But this is a no nonsense product that doesnt require humor to make a point