Kinetic Mobile Phone Charger – University Design Student Project

7:22 a.m. on October 26, 2015 (EDT)
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Hello Outdoorists and Adventurers alike,

From the title you may have some idea what this forum topic is about. Read on to find out more.

Firstly here is a brief introduction to who I am the goals that I have. I am a student at Brunel University London (brunel .ac.uk) studying BSc Product Design Engineering (see recent Brunel Design Projects here - madeinbrunel .com) and am in my final year. As part of the course there is a Major Project module that allows me the freedom to research and study a design opportunity and then develop appropriate solutions for it.

A potential gap in the market that I have noticed is for a mobile phone battery charger that can be charged up with kinetic energy. I am posting on this forum to find out whether or not the lack of this product truly is a “pain point” amongst outdoor enthusiasts, hikers, campers, etc. I would appreciate your feedback and thoughts on this.

There are currently three main types of portable phone chargers out on the market. Those are basic battery power packs, solar charging power packs and heat charging plates. All of these store and distribute electrical energy in a similar way, but vary in the ways that they gather that electrical energy in the first place. Basic battery power packs are typically charged with mains electricity via your wall plug outlets from a home environment. They a good source of charge for when you’re on the go, but require mains electricity access in order to recharge them. The solar charging power packs have the added benefit of harnessing energy from the sun. This is a pro because the energy is “free”, but you may not always have a good amount of sunlight (or none if camping at night) and the energy gathered is usually quite low. Heat charging power packs are emerging out in to the market more recently. The main pro is you can make use of unused/wasted heat energy from camp fires. The cons are that, they are usually quite bulky/heavy, require a source of heat, cannot provide charge to your mobile when they’re not hot (they lack a rechargeable battery power pack due to battery explode risks) and are relatively expensive.

A kinetic energy charger could outweigh many of the pros of the existing products above. Firstly, like the basic and solar powered battery power packs it could be charged using mains electricity. Like the solar powered and heat chargers, it would not be dependent on mains electricity to charge. It would also not be dependent on an uncontrollable variable such as sunlight and heat (difficult to get a good amount of heat in the cold and wet). Could be operated at any time provided that you have the ability to move (assuming that you’re hiking, etc. you probably do). This would all in make a truly “mobile” mobile phone charger.

I am aware that there are already existing concepts and products out there, such as: kompyuteran .com/2011/07/worlds-first-passive-kinetic-energy-charger-npower-peg/ , thevoltmakers .com/en/voltmaker.htm  and: getampy.com/ampy-move . The problem is that none of these really offer any “real power”. By “real power”, I mean enough electrical energy to supply a phone battery with a realistically usable amount of charge.

For the past couple of weeks, I have been prototyping with a set of home-built rigs to see if I can achieve “real power” with a portable kinetic charger and the results are heading in the right direction.

As mentioned above I would really appreciate your feedback and also to get a discussion going.

If you would like to contact me personally, my email address is 1206864 @my.brunel.ac.uk .

Thank you all for reading, take care and happy hiking!

David Dawood

11:14 a.m. on October 26, 2015 (EDT)
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There are 4 types of KE chargers intended for backpacking/expedition use that have been on the market for many years -

1. hand operated (I have had one of these for about 10 years, intended for charging cell phones and LED flashlights, since these need only a small amount of cranking or "squeeze" operation - that's a type that has a squeeze handle to spin the dynamo)

2. "Walking bouncer" - this is a type that you hang from your belt or pack that takes advantage of the bounce of your step to bounce the coil and magnet through one another

3. windmill - compact version of the wind chargers. This does require you set up camp in a breezy location

4. waterwheel - miniature waterwheel that you set in a flowing stream at your campsite.

I have not used types 2, 3, or 4 myself, although I have had trip partners who have. The hand crank type is the only one that has proven reasonable. I did have a friend who built a cart to haul his gear with a bicycle wheel generator to charge batteries (this was a research expedition where we had a lot of scientific gear to haul). It didn't really generate enough electricity to keep the batteries charged, plus added a lot of drag to the cart.

Personally, I use foldable solar panels along with storage batteries for expeditions of more than a few days, or just the storage batteries for trips of a week or two if I just need to recharge the headlamp, inReach, GPSr, cell phone, or sat phone.

3:27 p.m. on October 26, 2015 (EDT)
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Very interesting David. I don't consider lack of such a device a pain point personally. From the perspective of a recreational backpacker (me), the idea is to have no dependence on electronics at all. So it's not a big need based on what I do. But for folks like Bills S and others who are outside in remote places professionally, I could see it being very popular.

That being said, if this works, I could see myself purchasing one as a luxury.

Just one perspective....

Good luck!

5:54 p.m. on October 26, 2015 (EDT)
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There isn't just one hiker market, there are many, and each has its own unique needs/wants relative to electrical devices. Some, like Patrick, appreciate being unplugged for a few days, so clearly that is not your market. For many who do want to use battery devices it all comes down to weight-to-benefit ratio. For short trips just a spare battery or external battery charger (like Anker) provides all the re-charge power needed, so anything much larger/heavier is overkill. Some longer trips have stops in "civilization" regularly enough that one can re-charge or re-supply their phone and a small external battery frequently enough to stay ahead of the power drain. Where a heavier device (more than just a few ounces) will shine is longer hikes that don't have re-charge or re-supply options.

What is the means of capturing kinetic energy that you are contemplating?

11:41 a.m. on November 4, 2015 (EST)
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"There are 4 types of KE chargers intended for backpacking/expedition use that have been on the market for many years -

1. hand operated (I have had one of these for about 10 years, intended for charging cell phones and LED flashlights, since these need only a small amount of cranking or "squeeze" operation - that's a type that has a squeeze handle to spin the dynamo)"

Thank you for your comment.

The design that I am aiming towards is very similar to the first existing charger that you mentioned (quoted above). I am looking at improving the existing design to achieve a more efficient and user friendly kinetic charger.

What were the main pros and cons of this type of charger when you used it?

11:51 a.m. on November 4, 2015 (EST)
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JRinGeorgia said:

There isn't just one hiker market, there are many, and each has its own unique needs/wants relative to electrical devices. Some, like Patrick, appreciate being unplugged for a few days, so clearly that is not your market. For many who do want to use battery devices it all comes down to weight-to-benefit ratio. For short trips just a spare battery or external battery charger (like Anker) provides all the re-charge power needed, so anything much larger/heavier is overkill. Some longer trips have stops in "civilization" regularly enough that one can re-charge or re-supply their phone and a small external battery frequently enough to stay ahead of the power drain. Where a heavier device (more than just a few ounces) will shine is longer hikes that don't have re-charge or re-supply options.

What is the means of capturing kinetic energy that you are contemplating?

 

Hi, thank you for your comment.

I appreciate that there are power packs with high capacities. At the moment the aim of this charger is to be a power pack that has a reasonable capacity, with the added capability of being kinetically charged.

The final design will likely have a small generator within that is coupled with a series of gears. This gears would then be cranked with a lever to drive it. Using a high gear ratio, a reasonable speed can be achieved. The power generated will then feed in to a Li-ion power pack. Does that answer the question?

7:28 p.m. on November 4, 2015 (EST)
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I have not used the device for quite a while because of the cons I list. While a lot of progress has been made with electronics, several of the "cons" will still exist. For example, flashlights and headlamps now commonly use LEDs which are far more efficient that the old wire filament bulbs, so batteries last significantly longer. But people now carry more devices, which still adds up to a lot of batteries that need charging.

I could say more, but since this was your class assignment, it is up to you to dig up the answers.

Pros:

  • The unit was fairly small
  • The amount of cranking was acceptable for charging a cell phone


Cons:

  • At the time, it had only a single connecting plug, whereas currently there are many different plugs for cell phones.
  • It was designed for a single purpose (charging a cell phone with the matching connector, and no way to charge AA or AAA cells for flashlights and headlamps.
  • Charging AA or AAA cells required a lot of cranking (jury-rigged battery holder, since there was no battery holder available for the unit at the time - this was 10 years ago or so)
  • Currently, there are many electronic devices to be used in the field that the unit is not compatible with - mostly connectors for devices like inReach, SPOT, GPS receivers, wide variety of smart phones - note that many of these are likely to require a large amount of cranking for the original one I have.
9:30 p.m. on November 4, 2015 (EST)
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David:

I am a lazy hiker (that must be an Oxymoron).  I don't like cranking a water filter pump, hence my reliance on chemicals when the need is predicated.  Most people I know resent the filter pumping ritual; I wonder if they would be any more receptive to crank a device to drive the function of totally optional luxuries in the back country.  But then I am a Ludite when it comes to electronics in my car and backpack.  Thus my take is a crank powered device is more suited for gadget freaks and those who like to show off their toys.  A fun class project, but probably lacks commercial potential.

But running with the understanding this is a class project, consider harnessing the momentum of a pendulum.  The generator is hoisted into a tree and a rope tied to a heavy rock is suspended from a lever attached to the generator.  The swing of the rock pendulum actuates the lever, which drives the rotation of the generator.  Many details remain to be reconciled - how long is the actuating lever, how big a rock is necessary, and how many times must the pendulum be restarted, etc.  Another variant is using gravity, where a rope suspending a heavy rock is dragged over a capstan that drives the generator.  My ignorance shines brightly...

Ed

February 22, 2019
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