As our gadgets get more and more powerful, their energy needs increase, and the weak point of many mobile gadgets (especially as they get older) seems to be their battery life. Some device batteries last for hours and hours, and others, perhaps of a poor design, have you sprinting for an outlet, charger in hand, several times a day, just to keep your phone alive.
Even if you do have a great battery, you still need to keep it charged regularly, probably by using your house current, which is most likely generated by burning coal. And in trying to live lighter on the Earth, we probably would prefer to use renewable energy if we could. Here's a practical solar gadget that just might solve both of those issues: the SunVolt Portable Solar Power Station.
The SunVolt is a compact solar panel and charger that fits into a protective carrying case, which also doubles as an adjustable stand and features a big zippered pocket for holding devices, cords, and battery packs. When paired with the slim Solar Cache rechargeable battery (17 Wh / 3400 mah), the system is capable of either charging one or two devices at once, or simply charging up the battery for future use.
The SunVolt has a 13 x 12" monocrystalline photovoltaic panel, rated at 10W, but also comes in the Max version, which has a 17 x 12" panel rated at 15W. The carrying case, made from a tough ballistic nylon fabric, has two D-loops for attaching a shoulder strap for ease of carrying, and has non-slip pads on the bottom to help keep it stable when the panel is open.
Setting up the unit is incredibly simple. Just unzip the main section of the unit, then open the top half and move the bottom of the solar panel to one of the indentations in the angle adjuster. When the sun is high in the sky, the angle adjuster can be removed and repositioned to get a better angle for the panel.
The SunVolt unit has a cord passthrough into the big zippered pocket, where the Solar Cache battery or your devices can then be connected to the power circuit. It comes with several adapters, including a standard Female USB receptacle, and many other compatible TipExchange tips are available through Gomadic.
When I first got the SunVolt, I set it up in the sun, plugged in the Solar Cache, and came back several hours later to it being fully charged. I then plugged in my phone (iPhone 4S, 1432 mAh battery) to the Solar Cache, and in several hours, it was fully charged as well (though the Cache was down to about 50%). I was then able to get another full charge on my phone from the Solar Cache before having to set the panel out to charge it up again. On other days, I plugged my phone into the unit at the same time as it was in the sun (on the days I could go without a phone in the middle of the day), and again, in several hours my phone was fully charged.
I then experimented with my iPad 2 (6930 mAh battery) both ways, by charging it directly while in the sun, and then by charging it just by the Solar Cache. As expected, charging it directly (with the Solar Cache already charged) was the quicker method, and just using the Solar Cache alone wouldn't fully charge it (though it provided enough of a charge to extend my usage).
Naturally, charging the iPad, with its bigger battery, took a lot longer than charging the iPhone, and in trying to find a good way to position my iPad to charge for this longer cycle, I came upon what I can find is the only flaw in the SunVolt. The zippered pocket is *almost* too small to accommodate the cords, the Solar Cache, and the iPad, all at the same time. While the iPad did fit inside the pocket with the other pieces, the location of the charging port on the iPad meant that the connector had to kind of stick out on one side. It isn't really insecure, but there is something awkward about it.
I didn't sit next to the SunVolt with a stopwatch and time the charges, so unfortunately I can't say for certain exactly how long it took to charge the Solar Cache or my phone or iPad. Of course, I don't know exactly how long they take to charge when plugged into house current, either. However, by my rough calculations, it seems to take about 3 to 4 hours for my iPhone 4S to charge directly (in the sun, with fully charged Solar Cache), and about 6 or so hours to charge the iPad (in the sun). Charging times will vary, depending on the age and battery capacity of the device, but the time to charge my phone seems comparable with when I do plug it in.
The SunVolt weighs in at about 4.3 pounds, so it's not an ultralight device, but because it folds down to about 1.5" high, with the same basic footprint of a book or laptop, it's a convenient size to pack along with you. I can see this being a great addition to car camping and roadtrip gear, as well as being mighty convenient for powering the portable stereo out in the backyard.
Since I've had the SunVolt, I've managed to power both my iPhone and iPad with just solar energy, and the hardest thing about it has been remembering to go and adjust the direction of the panel every few hours to better face the sun.
Find out more about SunVolt at Gomadic: SunVolt Portable Solar Power Station
[I did receive a SunVolt unit for review, but the opinions in this piece are entirely mine.]