I think I'll share my experience with this product. This is basically the review I wrote for Amazon:
I used it during a 10-day bike tour to keep my iPhone 3GS charged. In strong sunlight it'd charge the iPhone from low 40s% to nearly full in about 3-4 hours. It will even charge, although slowly, in overcast conditions. It's not powerful enough to run the iPhone AND charge it at the same time, but that wasn't my intention. I just wanted to make sure the phone is charged up at the end of the day so I can do some emails, listen to some music and play some games at the camp. To speed up charging I would put the iPhone in the airplane mode. I was out of range most of the time anyway so there was no point keeping it on. I pre-charged the batteries at home before leaving using regular charger. Note, that it will not charge your USB devices if the batteries are not present and at least partially charged!
They also make more powerful panels that will run AND charge an iPhone at the same and do it faster. I will have a look at those for the next time. However, this one is the right size to attach it to a pannier or backpack. It even has convenient, reinforced holes in all corners. I used bongo ties to attach it to my pannier.
I am very happy with this little charger. But it spoiled me, so now I want a more powerful one
Other than it should just be an issue of soldering it in to a USB cable for your device or into a female USB plug so you can plug any USB device into it.
A friend suggested on could just use a 12-volt cigarette to USB converter to do both.
That said, I'm not an electronics wizzard. But at some point I may give this a go.
First though I want to exhaust all my options with 4AA and 6-volt power packs. In the end it may be lighter / simpler and more fool proof to just carry a cheap 6-volt battery, that is if 4AA batteries don't supply enough power.
Novarra Randonee (commuting Bike), Specialized Tarmac, Salsa La Cruz (rain bike), Co-Motion Tandem
Thanks for taking the time to write up your review. This is very useful information for what it does and doesn't do. It seems like there is a growing need in the product area so I expect to see more and more options.
This was also my first ever experience with solar panels. It seemed like the best idea at the time and it indeed worked out well. Although, like I said, for little more they now they have more powerful, although larger panels that can charge or even run a laptop. Although, as they get larger you lose the ability to be able to strap one to you pannier they way I did with mine. What amazes me about the new generation of cells is that they work even if there is no direct sunlight, although charging is much, much slower. I bet there will be something new and better by next Summer.
There is also this, a very useful gadget and for the price it's a no-brainer. In a pinch, you stop by a gas station, deli or pharmacy, get 4 alkaline AAs, stick them in it and it will charge your USB smartphone. It works with rechargeable AAs as well, but it's a little picky, it didn't work with one type of older MAHA batteries I have. It works quite fast, a full iPhone charge in couple of hours, and a set of fresh AAs is enough to recharge an iPhone fully TWICE and there is still juice left. Without batteries it weighs a couple of ounces, it has power switch and a battery indicator. And it also acts as a charger too, although I haven't used it that way and according to reviews it's not a great charger. Other than that it's a nice gadget to have in addition to a solar panel for a rainy day, literally
Just make sure your device doesn't require more than 800mA or it will work very slowly or not at all.
@AdamDZ Thanks. I'm wondering how necessary the batteries are if I've got a stronger solar cell. Would be nice to cut out the bulk, not to mention saving some cash. Might be worth the camble.
Thanks again for your review it has been extremely helpful. I suspect i like you will spend to little on my first unit, buy less then I need, love it, and get sucked in and want to drop $200+ on a better one. It's also got me thinking about where else I might find excellent reviews on the Brunton models, though you certainly have me sold on the PowerFilm. It occurs to me that there have to be other people that have tried these as well. Perhaps there are some product reviews on crazyguyonabike or adventure cycling association, or bikepacking.net. I've dug deeply on my usual favorite spots such as touring mailing lists, backpackinglight.com, but haven't found anything useful yet.