
During this review, I am going to be comparing the Sunforce 22007 Coleman 7.5W Folding Panel to the Goal Zero Nomad 7, which is the only other solar charger that I have had experience with and the product with which it is competing. Right out of the box, I was impressed by its compactness. I opened its velcro latch and spread it out. The charger has square, polycrystalline solar panels that make efficient use of space. The panels don't have a perfect appearance, as the horizontal conductive lines are inconsistent, but I don't expect this to hurt the panel's performance. Along the edges it has rope loops that are meant to be attachment points, which are comparable to the Nomad 7. On the back of the panel, there is a zipper enclosure that includes a power regulator which has a permanently attached 12 Volt adapter and a female, USB port. When you unzip the pouch all the way, the 12 Volt adapter tends to fall out. I couldn't wait to test it out, so I ran outside and pointed it toward the sun. At 3 in the afternoon on a clear day, I measured 5 Volts and .83 amps (A little over 4.15 watts). Compared this to the Goal Zero Nomad 7, which measured 5 Volts at .65 amps (3.28 watts) under the same conditions. I am guessing this difference in performance is due to the 0.5 extra watt of power rating from the Coleman Sunforce panel, as well as a better USB power regulator.
I tested the panel in low light conditions: An overcast morning, and it didn't produce any power, whereas the Goal Zero Nomad 7 did produce 5 Volts at 40 mA. This difference is probably due to polycrystalline solar panels vs monocrystalline solar panels, which are known for the low light efficiency. This was a very low light test.
I also tested it in a mostly cloudy midday sun situation: The Sunforce Coleman panel produced 5 Volts at .35 amps, whereas the Nomad 7 produced 5 Volts at .3 amps. They were both able to start a charging cycle on my phone under these conditions: 65 percent sky coverage according to the National Weather Service with stratocumulus perculidus clouds, with very little sky visible. This result reinforced my confidence in the Sunforce panel, given my foggy morning test the day before.
I purchased this solar charger to provide me with power while camping, so its compact nature is a plus, and it will be an invaluable resource when in an emergency situation. Knowing that you will be able to charge your communication and navigation devices with only the power of the sun is a great feeling. At this price, I couldn't pass trying it out, as I intend on getting more as gifts.
Compared to Goal Zero:
Pros:
Better output. at 3 PM 5 Volts .8 amps compared to 5 Volts .65 amps with Goal Zero in direct sunlight.
Smaller
Lighter (Even with 12V adapter. It isn't removable)
Cons:
12 Volt adapter tends to flop about when you open the zipper.
The usb port is very close to the zipper enclosure if you intend to enclose your charging device within the zipper. (This may have not been intended by the designer)
Perhaps slightly less low light performance.

I don't have any special equipment to give you hard numbers on voltage or amperage but I can tell you that it will charge my iPad2 to 87% with out the need for an external battery pack like my Nomad 7 system does.
The unit is not as "universal" as the Goal Zero system, but it does have a 12 cigarette lighter permanently attached for 12 volt charging and a single USB plug.
Edit 1-11-13
I'm updating my review and taking away 2 starts as it no longer functions after being exposed to moisture/rain. I plugged in my panel to charge a lawn tractor battery that powers my gate on a cloudy day. It started to rain, but I was not worried as the charger was out of the direct rain fall and it is "weatherproof". The next day I went out with my volt meter and was not getting any output from the 12 volt plug or any power from the USB plug.
I still think this panel is a good overall deal, but it is not weatherproof.
Buy Sunforce 22007 Coleman 7.5W Folding Panel Now
---Up date/ Feb 17,2013-----
My second one was broken. When I used it with putting on windshield of my car under the sun, and when I removed it
from the windshield in evening, this panel got quite hard to fold completely but I pushed it to fold it.
Since then it didn't create voltage. When I open it and change open angle from 0-270 deg, it won't make voltage, but
if I open it over 270deg, it makes 16.5V at cigar socket under full sunlight.
I am sure somewhere in folding part wire was cut in side.
I change my mind from my original review that it maybe not good product.
Anyway,
I wondered how this only two panels makes more than 12V.
I disassemble everything and found circuit board in the black box where the cigar socket wire and USB output are there.
On the circuit board, there's a L7805CV which is 5V,1A regulator for USB and MC34063A which is a switching regulator
IC that can be used for voltage step up/down or inverting to AC and it is used as step up converter on this circuit board.
I fed 9V to the circuit wires where solar panel power come in and cigar socket output is about 16.5V.
This is why this small 2 panel makes such high voltage.
DO NO USE it WITH SOLAR CHARGE CONTROLLERS.
Solar charge controllers often have reverse voltage when it is connected to battery at night.
This cigar socket has schottky barrier diode SS14 in the black box but it seems my 1st 7.5W solar's
circuit was broken by reverse voltage from charge controller, SK-6. SK-6 was also broken at the same time.
======Original review=============================================
This is my first solar panel. It has 1 USB port and 1 cigar lighter socket.
Open circuit voltage goes to more than 40V in full sunlight here in Houston. Typical would be 18V.
Short circuit current is about 600mA and slightly more, 12V x 0.6A =7.2W, so it work as it is advertised.
I do not use USB port so much so I do not know well about it drives my USB fan which other solar/lithium
ion battery couldn't drive.
Actually I bought this panel twice, first was from local shop about $46, 2nd in amazon, Amazon was much cheaper than the shop.
I also never see this power of folding panel in this price. It's really good price for folding/7.5W panel.
I broke my 1st one so I disassemble all cover of it and found it was quite well made,
It was really hard to disassemble. Glue was all over the back side of the panel except only
soldering connection points.
Panel its self is water proof but I would say 12V to 5V convert circuit would not be water proof.
As other review also reports, yes the pocket zipper should come from the other way, I agree that.
but this time I modified my panel so this won't be problem for me.
Anyway it's good for my first experiment of Solar charging. I'll step up to bigger wattage panel next.
Read Best Reviews of Sunforce 22007 Coleman 7.5W Folding Panel Here
I actually put this on my head and walked around with it during a rally. It baarrely kept my phone up. This is because the panels are crystalline and they don't put out much if they don't have full sun. On the other hand, the flexible thin film panels don't get as much power per square centimeter even when they have full sun. So it's a trade off. These panels performed as expected. When left in the sun and not moved they kept my device fully charged. And the price is the best you can find, name brand even, seems like it will last.
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I use it to charge the battery pack that I have. This in conjunction with the panels for the battery charge the 9200mAh battery in 2 days, without ever being plugged in. The battery pack fully charged, can charge up my ipad a little over one time from a really dead battery.