Bests & Worsts Reviews from Amazon

I'm conflicted as to how to review this. It works as a bank perfectly, and the wide range of output + feature like the compass, LED light, etc are great... BUT. I bought this for its main feature: The solar charging. Upon opening the parcel, the pamphlets are littered with disclaimers about how the solar charging "might not be as positive as you expect". I left it in my window sill over 2 entire days of sunny California weather and the bank charged 0%... So as a "Solar Power Bank", this product is useless.