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eyewall
2005-09-09, 04:54
Check this out... http://www.newscientist.com/article.ns?id=dn7970
You don't need no stinking batteries...

CanoeCamper
2005-09-09, 08:37
I just don't want to hear phones ringing in the woods.

dougmeredith
2005-09-09, 09:06
Phones don't bother me. Loud music I could do without.

Doug

Lanthar
2005-09-09, 14:08
yeah, i saw that on treehugger.com very, very cool idea. seems much more useful and realistic than the heel-strike thing that came out a while ago (the article mentions it as well)

Also, I find the "more comfortable to wear than a standard backpack" due to reducing peak forces comment interesting...

can't wait for an actual item to be released.

Kamen
2005-09-09, 14:38
If we are talking about a day pack it could be tolerable but for something like a 30+ pound load for long treks this would get tiring real quick. That kind of load is hard enough to haul when its stable, I cant imagine it bouncing around back there with each step. If I'm grasping the concept right, then with each downstroke (each forward step) the whole load would slide downward then hit a mechanical stop just as you put your foot down. That mechanical stop being strapped to your back would channel all the force from the load dropping right into your legs. I hate to be a pessimist but I could see this thing causing stress injury to knees and shins after only a few miles.

JAK
2005-09-09, 15:12
I would say it might be ok if you had to have alot of juice for some reason, like if you were a radio operator or doing research and humping a laptop computer around. I think solar panels also make sense for that sort of thing. My guess is too heavy and noisy and complicated for everyday light hiking. Also I am doubtful that energy from hiking can be recovered with something like that. What is more likely is that additional energy would be required. Perhaps I am wrong, but I don't like my stuff bouncing around. Anyhow, fun research project for somebody. No more crazy than what I get paid for.

Another way to go would be some sort of combined heat and power so that you operate your equipment and recharged your batteries while heating up 1-2 litres of water. You would use a thermoelectric device like this: http://www.hi-z.com/ At 5% efficiency you could get 1 ounce worth of electricity out of 20 ounces of fuel, which is 150 watt-hours. The problem is you can't charge batteries that fast, so it would be better to operate your radio or computer while running the thermoelectric device off of a single tea-light. This would supply 1.5 W of power and you could heat up water slowly with the rest of the heat.

The main problem with recharging batteries as you go is that with extra weight you might be better off just carrying the extra batteries you need in the first place. For example: http://www.siliconsolar.com/aa,_aaa,_c,_d_solar_battery_charger.htm A 10 ounce solar charge recharges 4 AA batteries in 10 hours which is 4 AA batteries per day, which aint bad. However, each AA weighs 1 ounces, so you would have to go on a trip long enough to use 10 AA to break even.

Lanthar
2005-09-09, 17:02
If I'm grasping the concept right, then with each downstroke (each forward step) the whole load would slide downward then hit a mechanical stop just as you put your foot down. That mechanical stop being strapped to your back would channel all the force from the load dropping right into your legs. I hate to be a pessimist but I could see this thing causing stress injury to knees and shins after only a few miles.

No, not hitting mechanical 'stops' and 'bouncing around'. What happens is it dampens the instantaneous loading you get everytime you step. Meaning you should 'theoretically' have LESS strain on your knees and feet each time you step.

It doesn't slosh around on your back, it's a controlled dampening.

Walk around for a bit with your knees and heel straight and coming down on your heels hard. now walk around on the balls of your feet (like you're supposed to) and with knees bending. Your body is built to dampen the instantaneous loading you get when you step. However, toss a load on your back and... well... not everybody's body can take that. Of course, simply reducing the weight carried goes a long way. However, if (for whatever reason) you need to take a little larger load, this will likely go a way towards making your body feel like the load isn't so bad.

One of the sites I read about this on mentioned the usefulness to college students lugging lots of heavy text books (plus it'll charge your phone and laptop while doing so).

btw - that idea of a thermo electric device with a tea-candle is interesting... that would make batteries for a zip stove redundant...

dropkick
2005-09-09, 17:48
I read about this in the paper today, and thought "waste of money". Sounds neat but isn't actually very well thought out.

A 10 lb. pack? For instant power you can carry a hand crank generator which only weighs around 5 lb. and does a good job - and our military has had these since WW2. If you want to charge batteries while on the move use solar cells. While they don't put out as much power they only weigh a few ounces, and how quickly do you need to charge the batteries anyway?

Also in my estimation it's a bad design idea.
-Exposed gears to get jammed, and catch in clothing, skin, etc.
-A generator on top both adding to making it top heavy and not very effecient
-Movement of the pack making for an unstable load and making balance difficult also possibly leading to friction injuries to the wearer.

If they want to make the pack generate power why don't they put some magnets on springs inside the hollow frame and wrap the frame with wire - no exposed moving parts, no dancing pack.
They need to look at the flashlights that are all the rage now (shake for light - works as above). Nothing very new in the idea, but it works.