Slashdot Mirror
Portable Solar Power For Portable Hardware?
Tjeerd writes "Because the 'green revolution' is accelerating, I felt it was time to get involved. Last week I started with buying a portable solar energy charger for my mobile phone. But soon I was thinking of also recharging my Asus Eee netbook with a portable solar energy recharger. I found things like the Portable Power Pack, Foldable Solar Chargers, and the Solar Gorilla. The Solar Gorilla looks quite interesting and might be able to recharge my netbook and fits nicely in a rucksack. But I would like some real-life feedback. If you have experience with these or other portable solar devices, what has worked for you?"
Before saying "I have found a way to save the planet!" check that the cost in planetary terms of the product is worth it:
http://www.genersys-solar.com/carbon-savings/carbon_footprint_solar-panel_manufacture.asp
seems to be saying that there's a reduction of the carbon cost when compared to other power-generation mechanisms, over the expected 35 year lifespan of the home-sized solar panels.
are the small, portable solar panels you're advocating as carbon-friendly?
I wrote a feature recently where I explored if it was possible to run all of the standard office gadgets from sustainable power - it includes quite a few product reviews.
Matthew Sparkes
The power brick for my laptop claims that it draws 65 Watts. The average incident solar power per square meter on Earth is 1000 Watts. If we assume a solar cell with 30% efficiency I would need 65/300 = 0.216 square meters of solar cell for my laptop. That's a square 46.5cm on a side, or around 18.3 inches on a side.
Not too bad, but not something I would carry with me unless I was severely limited in terms of power sources.
I had a Solio Classic to charge GPS logger and phone while hiking for multiple days. It worked okay, good in very sunny conditions (in northern europe) and not enough to keep up on clouded days. But it was stolen and now I have a Solar Mio 31 which works better, even in clouded conditions. It manages to keep the batteries of a mobile phone and GPS logger charged in average dutch weather, back pack mounted or behind a south facing window. As I also use it at home, I haven't touched the normal chargers in a year...
As for price or "greeness", they won't repay themselves financially or impactwise. But I see part of it as gaining experience with solar cells and it is nice to see your week long treks through nowhere in google earth...
I had done quiet a few bike trips and generally can't be without my iPod, PSP, and cellphone so I have had some experiance using Solar Panels previously, though never for something as power hungry as a notebook/netbook. Two years ago I purchased the Soldius 1 Solar Charger, seen here: http://www.thinkgeek.com/gadgets/travelpower/7d34/. I found that even stationary it really just drained my iPods batteries and made them unusable, as the change in voltages associated with clouds would cause the iPod to constantly redetect that the charging had started and illuminate the screen thus draining more power. I may have only gotten one meaningful charge or two out of it, in the two years I've had it. It also didn't charge some devices, that were USB powered, and seemed very brittle. This summer past, I had taken time off to go cycling for 2 months across Canada, and so invested in another Solar Panel, the SolarFocus SolarMio 31 Solar Charger: http://www.mec.ca/Products/product_detail.jsp?FOLDER%3C%3Efolder_id=2534374302697169&PRODUCT%3C%3Eprd_id=845524442620595. It was very durable, and I had it strapped on my rear rack, even in the worst rains. It also has a portable battery pack so you can charge during the day, and then have power for later, and it charges relatively quickly. I found that 4 hours would give it a full charge to the battery, (it is probably much better than this, as being on my bike rack and in motion means that it is not really positioned for optimum solar energy collection) and that would charge my iPod to 90%. It also has an external AC adapter to charge the battery overnight, and a USB port for 'most' USB devices. Some draw backs are that it didn't charge my Phone at the time, a Motorola KRZR, and after my trip I found out it doesn't charge my iPhone (which is kinda a disappointment). Another plus is that the battery is detachable, and while replacements/spares are expensive, it made it convient to charge at camping sights. They make an equivilant solar panel for laptops which is a bit pricer at CAD $595: http://www.mec.ca/Products/product_detail.jsp?FOLDER%3C%3Efolder_id=2534374302697169&PRODUCT%3C%3Eprd_id=845524442625524. Which is too rich for my blood at the moment, but if the quality is anything like this one, I'd definately recommend it. Finally some other words of wisdom: 1) The Solar Device compatibility list actually seems to matter at least for obvious devices not listed, just because it's USB doesn't mean it will charge it. 2) Getting a dead iPod (I had both a iPod 4G Photo and 5.5G Video) to charge is a bit tricky if you are charging straight from the sun in less than ideal conditions, as when it turns on, the screen comes on maximum brightness, and I believe stops charging for a moment, and will cause the iPod to turn off. I found that both the above would eventually charge by just booting it into Disk Mode a few times, eventually it would have enough power to stay on in Disk Mode and charge. Finally after two minutes rebooting it into Normal mode, so that the screen turns off resulted in a quicker charge.
"Are there practical crank chargers out there? "
Tons!
http://www.nextag.com/crank-charger/search-html
The CO2 produced by making those things is more than you'll ever get back from using them.
That myth really needs to die, once and for all.
You've phrased it one layer of indirection more than the standard claim (it takes more energy to make them than they will produce over the useful lifetime), but they reduce to the same concept (since virtually all of the CO2 "produced" during manufacture comes from the energy input).
A trivial economic proof should demonstrate this fact - The payback period for wind or solar runs around 10 years on average (a lot less in ideal climates, somewhat more in suboptimal ones).
The expected lifetime of such devices averages around 20-30 years (most importantly, more than the payback period).
It follows, then, that in order for it to take more energy to produce the device than it will generate over its useful lifetime, the manufacturer would effectively need to spend twice as much on electricity as they sell the finished product for... And that ignores other overhead such as labor and raw materials.
How many companies do you know of that sell at a massive loss and stay in business?