This little unit charges up the AAA batteries inside it from the sun just fine.

But I have not had as much success getting the stored battery charge transferred to a USB device. In my experience, the only charge transferred to a USB device is from the instantaneous power generated from the solar panel, not the charge stored in the batteries. So you would need to leave your USB device plugged into the solar power unit for several days, with the unit in the sun, to charge it up (which is not practical if you want to carry your USB device with you and leave the solar unit charging at home).

It might work better with a cell phone, I’m not sure (I was trying to charge up a Palm Zire PDA via the USB cable that came with the Zire).
Rating: 2 / 5