# Project: Charging devices with Eolic Energy

#### Kermit2

Joined Feb 5, 2010
4,162
Yes let us proceed with the project.

My mistake was a math mistake. I squared the wrong value inputting numbers in the calculator. The result was to make it seem your 6 inch blades could make more power than they actually can.
This means my advice is still true. You need much larger blades than you currently are trying to use.

Are you still wanting to use the whole fan unit or will you be substituting a permanent magnet motor with brushes?

#### Elboxd

Joined Oct 19, 2015
15
Yes let us proceed with the project.

My mistake was a math mistake. I squared the wrong value inputting numbers in the calculator. The result was to make it seem your 6 inch blades could make more power than they actually can.
This means my advice is still true. You need much larger blades than you currently are trying to use.

Are you still wanting to use the whole fan unit or will you be substituting a permanent magnet motor with brushes?
Thank you!

It would be awesome if we just talk about electronics from now on.

So, as I said, I was thinking about buying a few motors from the site I talked about. These are the ones: http://www.nmbtc.com/brush-dc-motors/engineering/select-flat/

What are your thoughts on this?

I'm thinking about dismounting the fan I have and using one of these motors. My question is, What would be the output amperage of this motor?

#### Kermit2

Joined Feb 5, 2010
4,162
Armed with a correct value of power for a 15 mph wind and a 6 in dia. Blade, we can determine what would be an ideal maximum.
Being generous with rounding, the 15 mph wind contains 3 watts of power in the swept area of a 6 inch rotor blade assy.
You can obtain about 60% of that power with a perfect generator. Considering the small size of the device and that it is a motor and is being used as a generator, let's say you get 30% of the available power.
That is 1 watt.
If you are generating 5 volts the you get 0.2 amps.

If you try to take more power out of the generator than the wind supplies, the blades stop turning.

#### Papabravo

Joined Feb 24, 2006
14,242
@Elboxd -- this forum is what it is, toxic or otherwise. We don't always get what we want, and we sometimes have to take what we can get. If you can start a forum that is closer to what you want, then by all means you should do so. Many people come here with unusual ideas and notions and the thread follows a predictable pattern. People react negatively to folks that show up without any evidence that their ideas are grounded in physical reality. Appearances and first impressions are everything. As unhappy as you are now, I would encourage you to come back to this thread after a period of time and ask yourself if maybe you did not bring some of this upon yourself and also ask if you bear some of the responsibility for the toxicity.

#### Elboxd

Joined Oct 19, 2015
15
@Elboxd -- this forum is what it is, toxic or otherwise. We don't always get what we want, and we sometimes have to take what we can get. If you can start a forum that is closer to what you want, then by all means you should do so. Many people come here with unusual ideas and notions and the thread follows a predictable pattern. People react negatively to folks that show up without any evidence that their ideas are grounded in physical reality. Appearances and first impressions are everything. As unhappy as you are now, I would encourage you to come back to this thread after a period of time and ask yourself if maybe you did not bring some of this upon yourself and also ask if you bear some of the responsibility for the toxicity.
Nothing useful about the project? Then I don't care. Please comment in another thread. WITH ALL DUE RESPECT.

#### GS3

Joined Sep 21, 2007
408
Check out ebay items 181741802038 , 121334421180 ,

Search ebay for Micro wind generator, micro hydro generator.

#### tcmtech

Joined Nov 4, 2013
2,867
So, as I said, I was thinking about buying a few motors from the site I talked about. These are the ones:http://www.nmbtc.com/brush-dc-motors/engineering/select-flat/

What are your thoughts on this?
Not really worth pursuing being the lowest speed unit they have is rated from around 1900 RPM and 13 mN/M of torque which in ideal conditions works out to less than 3 watts which if used for a generator might make half that at that RPM input.

I already made a suggestion on what sort of motor and its size to use for a generator and a estimated size of rotor to be looking for to work with the types of components you are asking about in an earlier post.

You can hope and want and dream all you like but the laws of physics always dictate the end design which if you are looking for a stable power source capable of 10.5 watts or more obviously you need to have a generator that is capable of producing at least that many watts at or above the voltage you need in a theoretically perfect working condition whereas practical application would dictate having a generator that can produce at least 2 - 3 times that as a minimum working size to design the system around.

#### takao21203

Joined Apr 28, 2012
3,695
Something is wrong here. There is no way in the world that fan is going to generate 50 or even 15 watts. And if it did that would be plenty to recharge a phone.
Why does TS write the link again and again?

For wind energy you don't just need a generator but one that's designed for this application. You need a regulator as well.

Same as with aviation parts. You don't send the stewardess to use the subway from airport to shop some lighter fluid even if it would do the job.

You need to order the exact chemical like written in specification and you need approval.

So I'd rather say trolley tech.

#### ronv

Joined Nov 12, 2008
3,770

#### takao21203

Joined Apr 28, 2012
3,695
The tiny motors bearings will have trouble with longitudinal movements, forces not completely different from aviation.

As well should I mention they aren't designed for such forces.

If you design the rest of the trinket with the same dimensioning chances are it will deform after only a short while.

#### Elboxd

Joined Oct 19, 2015
15
So Is there any chance to buy a generator? Not a motor but a generator. Not that big or heavy.

Any ideas on this?

Another question is: How much is the output amperage of the eBay's item 181741802038?

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#### takao21203

Joined Apr 28, 2012
3,695
In a larger generator the excitation current can be changed.

There are radios and lamps with windup generator but only worked for some minutes at times.

They have gearbox of course.

You could dissect the https://en.m.wikipedia.org/wiki/Armature_(electrical_engineering)

There are many different kinds of motors. They are optimised for a certain torque/rpm graph, torque from zero, acceleration speed and so on.

As wind speed is dynamic most will make poor generators and a generators needs regulation, could include voltage conversion and control of field excitation.

Brushed motors have limited life and the small kinds aren't serviceable tough I've seen 40mm motors with exchangeable graphite brushes. I actually have some of these, 24v slow spinners.

#### ronv

Joined Nov 12, 2008
3,770
So Is there any chance to buy a generator? Not a motor but a generator. Not that big or heavy.

Any ideas on this?

Another question is: How much is the output amperage of the eBay's item 181741802038?
Can't say, it is not spece'd. But not much.
My Chineese is not so good but I think you can get 6 watts out of this one if you can get it to spin at 2000 RPM.
http://www.ebay.com/itm/Small-Wind-Turbine-Generator-36W-12-24V-DC-Permanent-Magnet-Motor-Dual-Purpose-/161763982868?hash=item25a9e27e14:g:hyIAAOSwu4BVpcFF

#### Elboxd

Joined Oct 19, 2015
15
Can't say, it is not spece'd. But not much.
My Chineese is not so good but I think you can get 6 watts out of this one if you can get it to spin at 2000 RPM.
http://www.ebay.com/itm/Small-Wind-Turbine-Generator-36W-12-24V-DC-Permanent-Magnet-Motor-Dual-Purpose-/161763982868?hash=item25a9e27e14:g:hyIAAOSwu4BVpcFF
The project I have in mind gives a wind velocity up to 70 km/h (Don't ask me how, it's a secret lol) so having that settled approximately how much time would be needed to fully charge a smartphone? Having in mind the low amperage.

#### ronv

Joined Nov 12, 2008
3,770
The project I have in mind gives a wind velocity up to 70 km/h (Don't ask me how, it's a secret lol) so having that settled approximately how much time would be needed to fully charge a smartphone? Having in mind the low amperage.

I think an iphone charger is 5.1 volts at 1 amp. So this would charge it almost as fast.

#### takao21203

Joined Apr 28, 2012
3,695
If you see these cheap plastic propellers guess after a short time they wear out from UV cold and hot weather. Not specified for professional use.

The answer how long it takes?

Charging a phone battery isn't effective you loose almost 35 percent.

If you charge from a storage battery this doubles.

You get loss at suboptimal rpm.
The small generator doesn't have high efficiency.
And so on.

Just a few points so you could spend a longtime.

You put ad absurdum the claim you are engineer. Because you'd design as needed for a charging time that makes sense to you.

Your father works in aviation right? Because i doubt an engineer reasons like that

Really engineering related reasoning is a little absent

You didn't draw the plans with chalk on wooden floor didn't you.

#### takao21203

Joined Apr 28, 2012
3,695
It's kind of trolley.

Like charging a phone from a power bank.
You need much more maH charge.

Since at low levels the cheap unconverter might not be able to deliver full current.

And you get losses at least two times.

Similar, analog, you'd need another gearbox. And these two need considerable velocity pushing until they start to move.

Once spinning, they need less force to keep up motion.

Hope your research project gives new insights and a working wind machine.

Would you mind showing us?

#### takao21203

Joined Apr 28, 2012
3,695
The term eolic is common just not used in some contexts.

Don't large windmavhines have counterweights, flywheels and stuff like that?

#### tcmtech

Joined Nov 4, 2013
2,867
You put ad absurdum the claim you are engineer. Because you'd design as needed for a charging time that makes sense to you.

Your father works in aviation right? Because i doubt an engineer reasons like that

Really engineering related reasoning is a little absent
Similar thoughts here as well. Nothing that the OP has said so far remotely suggests he is an actual engineer of any sort let alone one that has worked in the aeronautics industry for 13 years. Personally I have doubts that either of his parents are Airbus engineers either.

Every question he has given so far can easily be seen to be coming from a child's level understanding and every reaction to a unfavorable response has shown the typical unjustified over the top reaction that spoiled child would give.
He clearly has zero understandings of basic physics plus near zero math skills and every link he has given relates to cheap small devices and items that are similar to what would be found in a kids toy. Also so far every reference anyone has given to anything slightly technical has been met with a blind eye and deaf ear which suggests that he doesn't have the slightest clue about what said items are or how they work.

Personally I suspect that even if a complete parts list, blueprints, and electrical schematics was given here he would totally ignore it simply due to having zero capacity to understand any part of it.
I know I have already pointed out what type of motor and its size would work well as a low speed high output generator plus gave the general dimensions of what size of blades set it would need including references to common off the shelf electronics devices that would work with it to give him a stable 5 volt power source from it as well. Zero acknowledgement to any of it on his part.

My guess is he is some spoiled teenage half wit brat that has lost his cell phone charger so many times his parents told him that if he wants to use his phone any more he has to figure out how to charge it himself.