Iwas looking online and came across these solar panels that attach to your backpack. They can charge anything from an iPod,cell phone, camera, etc.
Does anyone have experience with these things?
They weigh about 2 lbs which is a drag but I am sure I can make up for it somewhere else.
James
I had considered several solar setups for geek toys but after doing some research decided against it for a few reasons. Those solar panels charge based on the solar energy that they’re receiving, the problem for AT use is that you’re not going to be receiving that much direct and continuous sunlight to charge the panels. I talked to a few friends who worked on a solar car project at PSU and they informed me that such solar panels would be better off for car/train/boat use than hiking.
If you do decide to use the solar panels, you’ll need one of two things. One: to take a lot of 8 hour breaks in the sun, or, Two: an intermediary to charge before you charge a device like an ipod or cell phone. Those devices are not meant to be charged in a “little bit at a time” method, once you plug them into a charger they expect to charge the whole way, otherwise you lose battery life. A good intermediary would be a “trickle charger” for rechargeable NiMH batteries. The best simple solution I can draw using just text would be [solar panels] ====[switch]===[trickle charger]===[switch]===[device]. There is some energy loss here because you’re charging one device to charge another, but since cell phones/ipods/pdas require a steady charge you’re better off with this method. Just turn on the switch from the panels to the trickle charger when you want to charge and turn it off and the other switch on when you want to charge a device.
I really wanted to use a setup like this and I put a lot of time and research into such a solution, but I’ve decided (for me) it’s not ready for prime time. What I am looking into now is USB charging. You can find a lot of USB chargers for PDAs, Cell phones, Ipods, Etc, and USB runs a single 5v 500mA line, so if you know a bit about wiring you can make a lot work. There are a good number of adapters which turn outlet power into USB, and a few other devices which turn battery power into a USB connection. I’m going to try and bring only the one adapter and a connector for each device.
Good luck in your quest.
Wyatt
Wyatt (as yet trailnameless)
Wyatt-
I agree with your general conclusions. The first person to make a viable battery charging system (or some other energy source) for LD hiking will sell a lot of them. As a fun point of comparison, calculate how many AA batteries you could substitute for that 2 lbs of solar panels.
You can find chargers that will recharge your iPod from disposable AA batteries and if you insist on having an iPod that would be your best solution.
I’m an electrical engineer (and an iPod owner) and have been thinking about this a bit (the mind wanders when hiking). I’ve yet to identify any currently available technology that would be practical. Perhaps when the miniature fuel cells that are promised become available…
http://www.geek.com/news/geeknews/2003Dec/bpd20031212023044.htm
Using methanol for fuel cells has obvious advantages on the trail vis a vis stoves for cooking.
I will quibble with one thing. I think it’s fine to charge an iPod or similar NiMH device “a little at a time”. What you may be referring to is the “memory effect” of the older NiCd batteries in which failure to fully discharge the battery reduced the future ability of the battery to store a charge.
http://www.zbattery.com/zbattery/memoryeffect.html
-Arthur
Arthur
what about hand-crank technology? I recently saw a hand-crank cell-phone recharger. Seems like there’d be a way to harness leg action like a hand-crank, like a “leg-crank” to zap up your flashlight or camera batteries.
But a better option is film and pen and paper. However, I’d like to see the gadgets for the other sources. I could use something like that in the field for research, but usually good planning is enough.
Or what about the world’s smallest windmill?
tha wookie
Rolex (and a few others, I think) has a watch that’s powered by the continuous motion of your hand. As you walk, the motion charges it so you never have to wind.
A little more efficiency and that concept could eventually be adapted to higher-energy gadgets like PDAs. Maybe even make a pendulum setup when you get to camp and give it a swing every 5 minutes until it’s at a full charge?
Jeff
I’d always wanted to work on something that worked with the spring-loaded hiking poles like the Leki ones I have. Every time you compress the pole you send a jolt of charge into an AA battery mounted inside the pole. I haven’t done the math to see whether you could actually recover useful energy that way. I suspect not.
There are however “Electric Boots”…
http://www.wired.com/news/technology/0,1282,37276,00.html?tw=wn_story_related
The article is dated 2000. Don’t know whether these are available.
For the geeks like me
http://www.ttivanguard.com/montrealreconn/humanpower.pdf
You can Google and find all kinds of interesting things in this category.
-Arthur
Arthur
you could attach a small windmill near your as@hole and harness the power of improper diet… just a thought…
aswah
Aswah
In my quest to be geeky and weight efficient I think I’ve considered all of the options (save for aswah/tha wookie’s windmill idea). There are a lot of technologies that seem promising, but none that I’d be willing to risk on the trail.
Power will be important for me. I view nature and technology as complements rather than enemies, as I am a lover of both. I plan on bringing a PDA on the trail to save weight. My reasoning behind this is that I can carry electronic versions of guidebooks instead of the physical version, as well as replace the paper journal. Since I will be using the PDA for such important purposes, battery life IS a major concern. This is why I’m considering portable battery-powered usb chargers. The PDAs I’m looking at weight between 6 and 9 oz, 2 lithium AA batteries weigh about an ounce, and the charger adds another 4 or 5, thats under a pound for the whole package. I know it’s not the most ultralight thing to do, but for my geek side I think it’s worth it.
Wyatt (as yet trailnameless)
Too much technology for nature,first the packs,then the clothes and now communication devices other than shelter spiral notebooks. It would be interesting though, to see the feasibility of devises recharged by hydropower. Think about all the shelters located near streams or flowing water sources throughout the day. Too bad rumor has it that the Weathercarrot has retired from distance hiking,this would be something he may enjoy documenting. Peace
mike
I actually have to disagree with what people have been saying about solar power. During our '04 hike there was a guy who brought a solar panel and a PDA. The panel can be found here:
http://store.sundancesolar.com/porosepoposo.html
He said that he was able to drape the weatherproof panel down his backside during the day while hiking, which charged his PDA. He also said he was able to run his PDA right from the solar panel (used and charged in real-time). YOu will get a charge even with a really cloudy day. His pack weighed 34 pounds with everything including the panel, PDA, food, and water.
On the flipside… There is A LOT of tree cover on the trail. But, if you take your time and find lots of open spots to use the panel, you can make it work. Just remember, your $400 PDA is going to go through the roughest terrain it will ever see. Be prepared for it. If you’re just gonna use it for journals and reading, get an old palm pilot that lasts 3 months on 2 AAA batteries. They’re cheap and you won’t cry so hard if it breaks.
There is a fiberous material that will transfer pressure energy into electric energy. It’s being used now to make “muscles” for robots. By inducing an electric current onto it, it contracts, ie flexes. It also works in reverse. If it is contracted (by mechanical force) then electricity is made. That’s what’s in those “charging boots”. If you can find some of that and hook it up… There’s all your energy! By the way, I’m a computer engineer too. Good luck with the search!
Dave and Miranda
Dave and/or Miranda-
The original question was about an iPod (and cell phone and camera). I’m too lazy to look up the numbers but because the iPod has a hard drive and moving parts, it’s power consumption is far higher than a typical all-solid-state PDA.
I agree that you should be able to keep a PDA charged up using solar panels even with lots of cloud cover. But you’re right that the real solution, if you must have one, is to use a Palm Pilot that runs on disposable batteries. Of course, its storage capacity is far smaller and you can’t bring along your entire music collection which for me would be the whole point of bringing an iPod. Actually, my iPod is mostly loaded with audio books which would be a real boon on those days where you’re stuck having to kill time.
If you don’t actually turn on your cell phone, except to make outgoing calls, then the charge on the battery should last quite a long time and it would not need to be recharged except in town. If you leave your cell phone turned on and you are out of range of a tower (a lot of the trail) then the cell phone is going to work real hard at trying to find a tower and the battery will run down far more quickly than you might expect.
To be really picky (forgive me I can’t help myself), the “fiberous material” you refer to is actually polycrystalline and has the electrical property of being “piezoelectric” which operates exactly as you describe.
-Arthur
Arthur
Thanks for the added info on the polycrystalline. I couldn’t remember what it was called.
One thing on cell phones, it’s cold A LOT during the beginning and mid-sections of the trail. Batteries die and become almost non-functional in this kind of weather. I know of several cell phones with “full charges” that didn’t work because the batteries were too cold. Also, most of the time you are in the mountains at 3000 - 5000 ft. You’d be surprised at how often you get a signal; a strong one at that.
As for iPods… Well, they are battery hogs. 8 hours on a charge is nothing when you are hiking 10 hours a day and it’s 4 days before you hit another town. My suggestion would be to get a solid state device (ie PDA, or some memory storage device) that just barely does what you are looking for. Then get the biggest battery available. Unless you are MacGyver, you can’t plug those puppies into trees.
I do like the hand generator idea. I would imagine you could generate 5 - 10 watts of power with your hand or even more with your foot / leg. Although, at the end of the day… The last thing you want to do is work more and pospone eating. 
Finding some way to utilize the energy created by hiking (your steps, heat generated, etc) would be the most non-obtrusive way to get power, IMHO. A mini stirling engine?
Dave and Miranda
Environmental requirements
Not really robust enough for the trail IMHO.
Arthur
Maybe this is just what you are looking for…
http://www.scottevest.com/v3_product_info/index.shtml
How deep are your pockets?
Arthur