Power Generating Backpack


In the military, you have to carry tons of stuff. This is something we hear and see all the time. They are always trying to come up with ways to reduce the weight or quantity of the things that you bring into the field. This power generating backpack harnesses the natural up and down motion of your steps to produce power. This could reduce the amount of batteries carried into the field greatly. That’s what they say anyway, how many batteries do soldiers normally carry around? Aside from that point, we think it is pretty cool. We could see using this to keep our cell phone or GPS charged on long hiking and camping trips. You could also build something of your own to work similarly.

28 thoughts on “Power Generating Backpack

  1. As a former soldier I’ll chime in…

    The answer is TONS!!!!!!!!!! Batteries are actually a serious issue in the military. GPS takes them, night vision takes them, radio’s take them, etc etc.

    You need to have power constantly and all of that battery weight actually builds up.

  2. Batteries: 1-2 AA’s for you holographic sight, 2-4 AA for night vision, A lithium cell for your tactical light, 2-3 AA’s for you IR illuminator, batteries for your radio(s), batteries for your GPS, then there are all the batteries for your personal tech like a video camera, or maybe even netbook/laptop.

    Then you have to think about all the spare batteries you have to carry around. Night vision can eat through batteries pretty quickly. So this is definitely are real weight saver, especially if you have to do a long march. I imagine the Army is also looking towards their land warrior system. Last I heard, which was a while ago, battery life has been a real issue with that.

  3. Energy isn’t free. The electric power generated in the backpack comes directly from your legs.
    Because of the out-of-phase movement between the backpack and your back, the backpack will feel heavier when you move up.
    This only makes sense if this added ‘virtual’ weight and the added ‘real’ weight of the hardware makes enough batteries redundant.

    The defensetech writer even considers this as a power source for a robotic exoskeleton.
    Someone should point out basic physics to him.

  4. I saw something similar a year (or more?) ago. What has changed since then? Is it possible that a prototype was described back then, but now the thing nears mass-production?

  5. @Isaac – There’s already tons of power being converted to sound, friction, etc when you’re walking, and your normal backpack is moving up and down with your stride. You are performing Work when you raise the backpack up with each stride. You don’t get that Work back when you let it back down – rather, you have to perform *more* work to arrest its fall.

    With that slider, it looks like the E-generating backpack might actually be *more* efficient than a normal one – the load can maintain a more constant height above the ground. So, it’s quite possible that it will both generate power, *and* be more efficient than a normal backpack. I’m not saying it *is* more efficient – just that it is possible.

  6. More important than the AA and AAAs, ground-based air controllers (whether SoF or conventional) often have to decide whether or not to even take a piece of equipment (laptop, radio, laser) because of the additional weight. Much of this is battery weight. If this technology can offset the weight it would be a huge gain for that particular crowd; trust me.

  7. that would make it much better for your joints but the weight savings would be overshadowed by the added mechanism. it wouldn’t be worth it with such a large setup. this tech isn’t going places without a lobbyist.

  8. So the military uses disposable batteries exclusively?? And they’d like to replace all those light disposable batteries with one big rechargeable one?

    I’d imagine if all your batteries are rechargeable anyway, this thing is only going to add MORE weight for its own internal battery.. Just because you can now charge your laptop off physical exertion does not mean your laptop does not need a battery.

  9. I bet that tires you out in a hurry. It just takes more out of your legs as you run… Something else to consider is the amount of energy expended by the soldiers to generate the power vs. the weight of carrying batteries. Not to mention most of their things will need batteries to store this power as it isn’t a constant source.

  10. Despite the physical aspect required to charge the battery it could be quite useful.

    On the other hand it would also need an external charing method.

    Power cable/requirement standardization may also help with adoption. (IE: Do away with 2x AA for 3v and/org 6x AA for 9v. Standardize on ‘military power’ That’d help acceptance and make it truly useful.

  11. @albo,

    Nothing is free. With an ordinary pack, a step will raise the pack with a certain amount of force, followed by the down motion of the pack where the force is lower, giving the wearer a slight respite from the pack’s weight. The pack’s momentum gives you periodic rests.

    The generator robs the pack of its momentum to charge the batteries, forcing you to carry the full weight the entire time you’re walking.

    To compare it to a feeling you might have experienced, have you ever shouldered a heavy book bag with a “heave-ho” to boost it up high onto your back? That’s you using the momentum of a rigid pack. With a power generator attached that heave-ho will be replaced by a slow, sagging feeling, and you’ll just be dead-lifting a heavy weight until the generator bottoms out.

    I expect it would feel extremely unnatural and uncomfortable to an experienced backpacker. Soldiers, on the other hand, are used to taking whatever kind of crap they’re handed, so it probably won’t matter as much to them.

    Of course the stated idea is that the pack will be lighter due to the removal of the extra batteries, so the loss of momentum shouldn’t be as bad. Instead, I expect the military to say “that’s a 65 pound pack, and with the re-charger we took out 5 pounds of batteries. Now you can carry 5 more pounds of ammo.”

  12. I’ll take 5 pounds of ammo over 5 pounds of batteries anyday.

    That said, even if this does make carrying the backpack a little more difficult, I think that is far outweighed by the advantage of not just not carrying the batteries, but not burning through all your batteries and having no replacements. Portable power on demand in locations like the mountains of Afghanistan? Yes, please.

  13. One more vote for the point that this is useless. This takes all of its energy from your own muscles. The perceived effect is like running in sand. I would prefer running on hard surface than running on sand even with a pack of batteries.

    If you like this idea so much, I have some other ideas. For example attaching a wind turbine on top of your car. Great power!!! And freee, muhahahaaaa!!! Or the russian business model – steal a box of vodka, flush the vodka down the toilet, go recycle the bottles and for the gained money, go buy yourself a bottle of vodka and drink it. Thats a nice and profittable model.

  14. In response to all the nattering nabobs of negativity, the original concept for this first came up years ago.

    http://news.nationalgeographic.com/news/2005/09/0908_050908_backpack.html (from 2005)

    “Rome said “it’s actually more comfortable than a normal backpack.””

    “In addition, Rome and colleagues found the backpack altered the gait of test wearers, causing their up-and-down hip movement to become smaller.”

    “The researchers also learned that the self-powering backpack weighs only slightly more than a conventional pack—equivalent to carrying around an extra candy bar.”

  15. The company my mom works for was working on something similar to this, but it involved a (almost) frictionless magnetic fluid metal moving around in a container, and its efficiency was probably much greater.

  16. I have no first hand experience with this but is seems like when they are in a vechile, their packs are hung on the outside. Would be a good way to get charged before deploying especially where the roads are crap.

  17. @Nate – perhaps that would be the most convenient for them, given battlefield craziness. The best way, of course, would just be to plug their packs into the car’s electricity system rather than relying on pack movement.

  18. Id like to rig one of these up to my restless dog instead of a backpack to charge some batteries… what does he care, all i gotta do is throw the damn ball and hes happy. and im happy for the free-ish energy.. about time that mut supports his weight around here…

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