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?"

Comments

Come again. Because what?

[Anonymous Coward]

"Because the 'green revolution' is accelerating, I felt it was time to get involved."

Have another sip of cool-aid. Everybody is doing it.

Not saying that being more green is bad - just your reasons to do it.

And I'll quote the famous wise guy Kermit.

It isn't easy being green.

Watch out

[Bruce Perens]

There are a lot of underpowered units with inferior solar cells out there, for sale at very large markups. You probably want a folding unit, with reasonably durable cells. The ones I've seen aren't so great. There was a 6-watt folding unit at Fry's for about $100. That's 6 watts in full sun in optimal conditions, not nearly enough to operate and charge your laptop at the same time.

If you are running linux, the stuff in /proc/acpi/battery/*/* will probably give you the battery voltage in Volts and current draw in Amperes, and you multiply them together to get Watts. You need about twice that to operate and charge at the same time. Charging might be 60% efficient.

Re:Solar and handcranked are the way to go

[sumdumass]

Hey, wait a minute. I found myself in that exact same situation last year. Did you read my article in "outdoor geek's playhouse"?

Well, if you did, you would have realized that the answer was using the candy wrappers to fashion a sail on the cranks with your tongue then role over and fart while moving your ass from side to side to turn the crank. It helps if you ate microwave burritos before the hike. You then think about using the force when you use your tongue to dial 911 and wait for the ranger to show up talking about putting on his robe and wizard hat.

Re:How many watts does it produce?

[TheLink]

One link said 30W for 490 UKP. Another had a 60W product for 600UKP. So I shall use this.

Assuming domestic electricity in the UK is about 16p/kwh ( http://www.britishgas.co.uk/pdf/Elec%20Price%20guarantee%202008.pdf )

600UKP = 3750kwh worth of electricity.

Assuming very generously you get that 60w for 8 hours of sunlight (laugh if you're using it in the British Isles), this means 480wH a day = 0.480kwH a day.

3750/0.48 = 7800 days = 21 years for that panel to make 600UKP of electricity.

It does not appear to me to be a "Green" _alternative_ to mains power.

BUT if you were intending to be temporarily in the middle of nowhere, that 600UKP for 60W weighing 2.6 pounds may start to look like a bargain. It will cost a lot more in time, resources, and environmental damage to pull power cables to your ever changing remote location.

So is it a good option for _portable_ power?

I don't know - it might still be worth considering other sources of power dynamo, generators, etc.

2.6 pounds = 1.2kg. 1.2kg of vegetable oil contains 31MJ or 8.6kwH. It takes 143 hours of 60w to produce 8.6kwH - that's 18 days of 8 hour sunlight.

Yes there are inefficiencies in converting cooking oil to electricity, or diesel to electricty.

So do more thorough estimations/calculations to see which makes more sense for your scenarios.

If you're only spending a short time from mains power, it probably makes more sense to carry enough rechargeable batteries to last the whole time.

Re:This isn't "green"

[stranger_to_himself]

The CO2 produced by making those things is more than you'll ever get back from using them.

Make one car journey less (eg. the one needed to go and buy the solar charger) and you'll probably achieve more green credit.

Probably right at the moment - but buying into this technology now will help drive development which hopefully will bring far greater long term benefits.

Re:It wouldn't work

[capnkr]

Maybe I should get my calculator out before continuing?

That might help, but moreso - doing some research into real-world applications will teach you more than anything else...

Solar panels may produce electricity from non-direct light, but it isn't much. With a panel that small, I would be surprised if it would produce even millivolts, without direct lighting. I managed to wear down the 200+aH house battery bank on my boat over the course of 7-10 days primarily just by using the radio, when my relatively large 80W solar panel was set obliquely to the sun. That is the reason many cruising sailors use devices like the James Baldwin's Solar Tracker. You NEED to keep the panel face approx 90* to the suns rays in order to consistently produce usable amounts of electricity.

So many people living 'on the grid' tout solar as the new energy source that will solve all our problems, but when you've lived with it for a few years, you will begin to understand and appreciate some of the inherent limitations. That is the reason that most cruising sailors (people with experience living OFF the grid, completely, for months or even years at a time) use a combination of energy-producing methods instead of just one. Solar and wind (via small windmill-type generators) are the most common methods.

Re:This isn't "green"

[bigmouth_strikes]

Not rubbish at all. There are plenty of small photovoltaic panels that can power/recharge almost any powered gadget and there is little point in replacing those as often as the gadget. It all comes down to connectors. We have all this beautiful technology and we can't agree on their interfaces.

Re:This isn't "green"

[crashumbc]

We have all this beautiful technology and we can't agree on their interfaces.

The interfaces are intentionally designed not to match... Blame the greedy Manufactures that want to sell a new car charger with every cell phone...