O Solar Pioneers! Foldable, Rollable, Flexible Solar Panels

August 1, 2008

By Anna Moya Underwood.

NASA engineers invented super-thin portable solar panels that can capture an electric charge in remote places, from the edge of a redwood forest to outer space. Now some U.S. firms are making these flexible panels. Some vacationers are back-packing these panels into a campsite in a wilderness area for firing up small electronic devices once their internal batteries have lost their charge. Of course we want to cut fossil energy by using solar power whenever we can, but we still have to ask questions about how our end technology is affecting the environment and social relationships. Here are some questions to help sort out what electronics to take: Will the device help if things go wrong? Will it enhance our understanding of nature or our time with those present? Is the device worth the cost of the back-up solar panels?

Cell phones, for example, can be both deleterious and helpful. Imagine hiking a flower-filled mountain trail with elk scat in Colorado in breathless quiet along with someone, only to hear a falsely cheerful melody. Your friend soon has a cell phone clamped to one ear, stares past you and speaks in a loud voice. Suddenly and reluctantly you are privy to a one-sided conversation. Nature’s spell has dissolved to irritation.

On the other hand, if cell towers are nearby to send a signal, a cell phone can help out in an emergency. They can take snapshots, even videos, of the magnificent trail. They can access the Internet, and receive reassuring text messages from home about the dog or chickens—or children. Some contain tiny keyboards and act as simple computers. You might indeed want a solar panel to re-charge your cell phone in the wild. Or not.

If you get lost, the personalized GPS (Global Positioning System) unit tells you where you are, based on a signal bounced off a satellite. Small cameras go in some backpacks—to frame perfect pictures of wild animals or wild plants. Lanterns that light your card game in the tent at night can get their power from the sun instead of kerosene. These devices are clearly useful.

Most of these electronic devices have internal batteries. You would charge them before your trip, naturally. But if you use your carefully chosen device a lot and deplete the charge, or use it on the top of a mountain, you might be glad to unroll or unfold a super-thin solar panel, face it towards the sun, and hook the gadget to it.

Incredibly, these very tough panels roll to an 11 or 12-inch by 4-inch diameter tube, ranging in weight from about ½ to 2 pounds, or fold to the size of a book, about 11 by 9 by 1 inches, about the same weight as the roll-ups, depending on the wattage of the panel. The wattage choice varies from 5 watts to 20 watts on the roll-ups, 6.5 watts to 55 on the fold-ups. Both types are USA made and vary from about $140 on the lowest wattage panel to $400 on 20 to 25 watts panels.

In some cases your portable, flexible solar panel will connect to a 12-volt battery back at the campsite, and the sun-charged battery will charge your small electronic device. In other cases, the panels can connect directly to it. In the case of a laptop, an optional “female cigarette lighter adapter” can be ordered for $10 along with the roll-up solar panel. The female adapter connects to the panel itself. You should have a “male end DC to DC adapter” that came with your laptop. (If not, you can buy or order one at Radio Shack.) The DC to DC adapter goes into one of your laptop ports, and the male end fits into the female cigarette lighter adapter in the solar panel. Voila! Also, the roll-up solar panels have to flexed to conform to a surface facing south; grommets in the margin can be used to tie them down. (Plus, you can link the panels together for more watts.)
How do you know what power panel in watts to get? Your electronic device should say somewhere on the case what it requires. For example, my 14-inch Dell laptop says on the back that it uses 19.5 volts and between 3.34 and 4.82 amps. To know the watts it takes, the formula is W=VA, or multiply the volts times the amps and you have your wattage usage. Estimating my laptop’s energy use in watts, 20 V x 3A is 60 watts. To link together three roll-up 20 watt panels would cost me $1200; the 55 watt foldable solar panel plus a 6.5 watt one would cost almost that much. So if you just had to use your laptop on a trip and might need solar panels for back-up charging, it would be much less costly to bring one of those cell phones with a tiny keyboard and simple computer and Internet capabilities. But maybe you are writing on the spot for National Geographic and can invest the money for more watts!

One safeguard for the lower wattage panels is a built-in voltage cap to permit a direct charge to small devices and prevent damage from low-light reverse power flows, as might happen if a cloud passed over the sun.

Though rather expensive, flexible panels are durable, weatherproof and create a portable power station for hikers, campers, trail forgers, pack riders, boaters and others who like remote areas. Check www.realgoodscatalog.com , or call (800) 919-2400 for answers to your questions about solar power for small electronic devices.

Finally, when you’re on an adventurous trip, should you take along the iPod or new video game? Ask yourelf: Will it help you see and hear more of what’s out there than you ever imagined? Or save your life?

The Underwoods’ A.C. solar electric system for their 1800-sq.- ft. house six miles from Las Cruces has 10 60-watt and two 120-watt PV modules, 12 lead acid batteries, a charge controller, an inverter/monitor, a power switch, a combiner, and three disconnect boxes.

Written by Anna Moya Underwood · Filed Under Sustainability