This is getting offtopic here, but I'd just like to point out to contradict your statement that the Solio chargers are 100% carbon neutral; the company plants a tree for every device purchased, and I don't have the exact numbers but they're on the site somewhere... it's something like every unit requires X amount of energy to produce, and if used every day for a week saves the end user X + 10 amount of energy.

As far as performance, just don't try to use the thing through a tinted automotive window (even a slight UV protection tint) as it actually blocks the energy from getting to the solar panels. (ever tried to wear those "transition" sunglasses in a car with a UV tinted windshiled? same problem)