I enjoy hiking but I don't give away some gadgets like flashlight (if hiking at night) and a smartphone for the GPS. I recently took a long hike that went well into the night (about 18 hours hiking straight, with a few rest stops) and found that my hand crank flashlight and USB charger are quite cumbersome to be driven while walking.

Do you know if there is any device that would draw power from other body movement that would have enough power for a flashlight and a USB charger?

  • 1
    Would you consider portable solar panels as an acceptable equivalent?
    – Francky_V
    Dec 11, 2016 at 17:33
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    youtube.com/… Dec 11, 2016 at 17:39
  • IIRC pornhub made/makes a device you can charge your phone with, that attaches to your wrist
    – RozzA
    Dec 11, 2016 at 21:07
  • @Francky_V if it can charge a cell phone as I go it would be ok. It would be a concern mostly if it does not work properly under rain or if I can't get over night in a single power. Dec 11, 2016 at 21:49
  • 1
    @Aaron It is called WankBand and it was never sold. It was more likely an April Fools’. Dec 13, 2017 at 17:39

4 Answers 4


There was a kickstarter for shoe soles that can charge a battery. The company is called SolePower. They ran a Kickstarter and were successful. I have not followed the company myself, but they do seem to have progressed since the kickstarter days.

In a short summary, your walking will charge a battery bank attached to your ankle.

I am not trying to re-purpose how you hike, but these are my thoughts on meeting your requirements.

  • Purchase an LED headlamp that utilizes one AA battery.
  • Purchase a package of 2 Sanyo Eneloop batteries with their USB charger.
  • Purchase these soles (when available, if not already).

You wouldn't have to carry anything anymore really.. an extra AA, your phone and a USB cable for you phone. Battery strapped to your ankle, lamp on your head.. sorry, ran off topic a bit.

SolePower soles and shoes are what I came across a while ago when I was doing my research. (I ended up getting a BioLite for camping :D)

  • Good answer but maybe go with few batteries so can charge the up during the day. Can still use a headlamp with two AA.
    – paparazzo
    Dec 11, 2016 at 17:39
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    Thanks for the answer. I will definitely take a look into these soles. I think that using anything that will eventually discharge may not be suitable since I want to go a bit more hardcore in my future hikes. Dec 11, 2016 at 18:15
  • @Paparazzi - yeah, I myself use a headlamp that takes one AA. It lasts more nights that I can think of, over 10 full nights. The suggestion for the SolePower was more so as emergency to charge the phone. I also would not necessarily use it myself, however, it is really cool and it does address the poster's concerns :)
    – Seanland
    Dec 11, 2016 at 20:31
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    And I gave you a +1. Excellent answer to the stated question.
    – paparazzo
    Dec 11, 2016 at 20:45
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    another kickstarter for a flashlight without batteries: lumen - unfortunately seems like the creator abandonded the project
    – x29a
    Dec 12, 2016 at 7:09

I get the stated question is generate power

But if you are just looking for power a battery is very weight effective. One AA battery is only 0.8 ounce. A pair (1.6 oz) on low power will last about 4 hours.

The SolePower is a cool product and good answer but all set up it is about 24 oz without batteries. Add in 2 sets of batteries 27 oz.

You would need to hike 4 hours into the night for 16 nights for the charger to be weight effective. Even an endurance trekker cannot hike 4 hours into the night for 6 nights let alone 16 nights. On top of that it is your energy charging the battery.

  • I agree - I think that part of the problem is that the question is already suggesting a preferred answer which may not actually be the best way to solve the heart of the matter (extend power autonomy while hiking).
    – Francky_V
    Dec 11, 2016 at 21:25
  • @Paparazzi It does help your answer, but indeed my main concern is about cell phone charging. Dec 11, 2016 at 21:52
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    @GabrielDiego Do you really need to run your cell phone full time. You could get an easy week if you just turn it on a few times a day to get GPS. But you don't seem concerned about weight.
    – paparazzo
    Dec 11, 2016 at 22:30
  • I rather doing so since my cell phone takes a while to boot up and sometimes I do off trail, so I need to keep track of the trail. And also I take pictures from time to time. Dec 12, 2016 at 1:06
  • My current solution has been to carry multiple cell phones and batteries. 4 in total. Usually my old ones which are smaller and will hurt less if they damage or stop working due to the punition. Even so the batteries drain very quickly due to the GPS tracking. Dec 12, 2016 at 1:08

The U.S. Army had a power-generating backpack developed, within which were ballast weights which moved with the wearer's marching motion, and which were coupled to some sort of generator.

It looks like this item has been commercialized now:


  • Thanks for the answer. Unfortunately this backpack seems to be not available for sale, at least to the general public. Dec 8, 2017 at 6:57

Ignoring the usb charger and just focusing on light. There are a multitude of mechanically powered lights. Personally I have several of them. IMHO the most effective and efficient are the Shake Type originally marketed under the name "NightStar jP Shake Flashlight" The best are relatively expensive USD $60+ I have an original NightStar JP that is more then 10 or 15 years old, It has spent hundreds of thousands of miles sitting on the floor of my vehicle next to the drivers seat and still works (just checked)

The reality of mechanical energy to light is usually less impressive (shorter light time) then advertised. There are currently several "shake lights" on the market and some made by the same NightStar company. All the models I have tried have been a disappointment, even the NightStar JP which is the best I have seen or used really only gives a small amount of light, and 2 to 4 minutes of it for a a few seconds of shaking. On a clear night, with just the stars for light, I would not use it to light my path.

The magnet is strong, and can be a risk to any sensitive electronics placed near it. But the magnet also works well to keep the flashlight in place next to the metal base of my car seat.

Having said that the best is disappointing; if my NightStar JP was lost, I would buy another. It does not give a lot of light, and it does not last long. But it always works. It is possible to walk and shake it at the same time. When it is dark and overcast and you literally can not see your hand in front of your face and you don't remember when the last time you checked your flashlight was, a quality mechanical light (that uses a capacitor NOT a battery) can make all the difference.

If you are concerned about ease of use, weight, cost and brightness of light, one or two small LED, battery operated lights, with a supply of spare AA or AAA is probably going to give you more light, for less money and weight then a mechanical light, for trips of several days.

Other answers address, the practicality of spare batteries for short term electronic requirements.

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