On the right hand side is a pocket where you can store your devices so they don't get incinerated by the sun if you're outside. It has a little box with two USB ports:
When you plug a device into the USB port (especially when it's cloudy outside or you don't have good sunlight where the charger is), the device may not recognize that it's charging. My iPad Air 2 recognized that something was plugged in, but the charging icon didn't come up. I decided to test the charger on my iPad Air 2 before I went to work yesterday. I plugged it in at noon and checked it when I got home at around 10:30 pm. The charger fits pretty nicely in my window:
So I was gone all day and let my iPad Air 2 charge. This window wasn't getting a crazy amount of sun yesterday (and it isn't really today either, I should have bought one of these and tried it out a few months ago). Still, it charged my iPad Air 2 about 6% while I was gone. That's not too bad for a tablet that has a massive battery in way less than ideal conditions for the solar charger. (I tried the solar charger a second time on a very cloudy day with pretty much no sun. It charged the iPad Air 2 about 2% while I was gone. That should be the minimum it can do in a day.)
I've decided that I'm going to order an external battery from Anker and use the solar panel to charge that in a different window that gets more sunlight. I can then use the battery to charge all of my mobile devices at night (and it'll be a lot quicker). I looked into it and the Anker solar charger can only charge external batteries as large as this one (it's an Anker 16000 mAh battery). So that's what I ordered. It'll be here in a few days. All things considered, I think I'll ultimately save some money on my power bill next month and in the following months.
UPDATE: The battery arrived. Ultimately, my solar panel was able to charge my iPad Air 2 about 11% over three cloudy days plugged in for about 9 hours of cloudy sunlight per day. The battery came about half charged with two blue lights that would blink on and off. After a couple of days, a third light is now blinking (there are four lights total). Here's what it looks like plugged in to the solar panel:
The battery, when fully charged, should be able to charge my iPhone 5 around 6x or my iPad Air 2 around 1.3x. Here's some closer shots of the battery:
Once again, if you'd like to check out the battery on Amazon, here's the link: Anker 16000 mAh battery. It has two USB ports to charge up to two devices at once.