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EEVblog => EEVblog Specific => Suggestions => Topic started by: danielrcoates on April 19, 2016, 12:40:35 am

Title: Kinetic Energy Charging
Post by: danielrcoates on April 19, 2016, 12:40:35 am
The other day on an MTB ride my phone battery died and I remembered that there are watches that charge from movement, so I started looking into it

From what I can tell, in a or so technical form it's based on a magnet moving through an induction coil (please, correct me if I'm wrong)

I did a little searching and came across this site http://www.saikatbiswas.com/web/Projects/Livecell.htm (http://www.saikatbiswas.com/web/Projects/Livecell.htm) and thought it could make an interesting video

Thoughts?
Title: Re: Kinetic Energy Charging
Post by: Brumby on April 19, 2016, 01:02:32 am
Wind up and shaking torch charging systems have been around for quite a while - so I suppose it was only a matter of time before someone took it a step further.

There are two concerns I have, though.  The first is the reliance on movement for the charging to take place.  Unless their is some regular routine where these units get jostled, they could end up being discharged and someone isn't likely to want to go for a 5km jog or sit on the lounge and shake them briskly for half an hour to charge them.  Relying on a person to remember to take an action is a sure fire way for an unreliable result.

The second is the amount of power - how much can be generated and how much can be stored.  They mention cameras - but I would not be confident in relying on this system too much.
Title: Re: Kinetic Energy Charging
Post by: IanB on April 19, 2016, 01:35:00 am
Bicycles are frequently fitted with dynamos or generators to power lighting at night. All you need is a suitably small and lightweight voltage regulator to take the generator output and convert it to 5 V DC for device charging. Then you just dock your device on the handlebars and charge it while you ride. Simples!

(This is especially useful if you use your device to track time, distance and location during your ride.)
Title: Re: Kinetic Energy Charging
Post by: CatalinaWOW on April 19, 2016, 01:52:18 am
More practical for bus riders are the boots that steal some of the compression from each footstep.  They can actually generate a fair amount of power, though the more power generated the more it is like walking in deep sand or mud.  The power captured by watches is not nearly enough for cell phone power.
Title: Re: Kinetic Energy Charging
Post by: danielrcoates on April 19, 2016, 07:23:56 am
Bicycles are frequently fitted with dynamos or generators to power lighting at night. All you need is a suitably small and lightweight voltage regulator to take the generator output and convert it to 5 V DC for device charging. Then you just dock your device on the handlebars and charge it while you ride. Simples!

(This is especially useful if you use your device to track time, distance and location during your ride.)

That's not a bad idea, however I was more on about the practicality of a general charger for the phone, than one specific for my needs

More practical for bus riders are the boots that steal some of the compression from each footstep.  They can actually generate a fair amount of power, though the more power generated the more it is like walking in deep sand or mud.  The power captured by watches is not nearly enough for cell phone power.

The boots thing sounds interesting, and your right on the small amount of power made by watches, but a scaled up version? I was thinking more of a trickle charge type thing, that may only put a tiny amount into the battery over time could keep it at a reasonable level, or at least extend the life of the battery for a short period
Title: Re: Kinetic Energy Charging
Post by: vk6zgo on April 19, 2016, 07:43:01 am
Back in the windup watch days,there were quite a few "self-winding" watches which used the wearer's motion.
The self winding mechanism was usually the first thing to fail.
Title: Re: Kinetic Energy Charging
Post by: CatalinaWOW on April 19, 2016, 03:16:10 pm
Data is good, and data collected yourself is always more informative for some reason.  Go buy one of those crank flashlights and one of the shaker style.  Take them apart so you can access the generator output and measure the output.  Then think of how the effort you are doing and the output you measure compares with what you want.  See if it is consistent with your proposed purpose.