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Using Arduino => General Electronics => Topic started by: falexandru on May 27, 2018, 12:55 pm

Title: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 12:55 pm
I am working on a very simple charger based on a Savonius (vertical axis) wind turbine charger.

The basic principle is the same as in my previous project using a solar panel to charge 3 NiMh AAA batteries.

The difference comes from:
a) the Savonius rotor offers much lower voltage than a solar panel (namely 1-3 V); reason to use it instead of an horizontal axis (propeller) is it start offering power from lower wind speed
 
b) the out put voltage is much more variable as a result of very variable wind speed

I avoid the dedicated push up power modules as being very hidden in terms off explanation.

So I plan to use a modified Joule thief circuit.

The compont's list (modified from the internet source) is the following:


NPN Transistor - one I can find in my shelves (original: 2N2222, 2N3904, or similar)

4.7 uF capacitor (the scheme provides for a 0.01 microfarad Capacitor) - I made this modification to allow more energy to get stored when the wind blows instantely

330 microfarad Capacitor

470 Ohm resistor( instead of the original 1 kohm resistor) - I made this modification to reflect lower voltage selected (4,7 V instead of 6 V in the original design)

4.7 V Zener Diode

Shotky Diode (instead of a regular diode in teh original design)

Perf Board

1 toy electric motor 3-6 V.

various PVC profiles, screws.

The original design (which includes a common diode and a 6 V diode) is here:

http://www.instructables.com/id/Joule-Thief-Low-Voltage-Battery-Charger/ (http://www.instructables.com/id/Joule-Thief-Low-Voltage-Battery-Charger/)

I clipped the schematics from this web-site is attached.

The modified by myself circuit is to charge a series of 3 AAA NiMH Batteries 800 mAh (the same as in my previous solar charger) which at its turn will light an white LED  (the same as in the previous solar charger).

Is somebody please more familiar with the Joule thief circuits to be so kind to give me an opinion about whether this modified circuit may work? Thank you very much!
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 01:52 pm
I found this explanation about the "Joule thief" based convertors:
https://www.youtube.com/watch?v=wJU7AJgERG8 (https://www.youtube.com/watch?v=wJU7AJgERG8)

Far more complicated then I want, but I found it useful anyway.

+++

From the internet, these circuits can "extract" energy from an exhausted 1.5 alkaline pile. Although I could not find the minimum voltage of such circuits to work as input, I guess it is as low as 1V, based on the values of voltage in piles that cant be used anymore.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 02:58 pm
Gosh, it would be so nice if seasoned posters, such as yourself [OP], would embed your images in the text, rather than just attaching them, thus relieving those of us, who are want to apply our precious time to your cause, of the burden of downloading the flippin' thing ourselves!  If you don't know how:

http://forum.arduino.cc/index.php?topic=364156.msg2510120#msg2510120 (http://forum.arduino.cc/index.php?topic=364156.msg2510120#msg2510120)

But, in the wake of this lack of this, permit me:

(http://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=259548)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 03:03 pm
From the internet, these circuits can "extract" energy from an exhausted 1.5 alkaline pile. Although I could not find the minimum voltage of such circuits to work as input, I guess it is as low as 1V, based on the values of voltage in piles that cant be used anymore.
I've seen them function all the way down to 0.5V -- that during a continuous run.  It takes a higher voltage to start the thing -- ~0.8V, but it varies.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 03:22 pm
I thought is much better to leave the image in the attachment. :-(. Reason is to have only a small number of scrolling down moves, based on the psihology of the number of clicks. Having everything  in one screen only allow eyes to "scroll", instead of hands + short term memory.

But well, I will try do do it from now on, since people feel more confortable with this "on screen" method.

Anyway, I cant figure out how to enable the image in the text. If I want to insert a pic, the interface asks me for the URL. 

The link you posted does not work. :-(
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 03:37 pm
I thought is much better to leave the image in the attachment. :-(. Reason is to have only a small number of scrolling down moves, based on the psihology of the number of clicks. Having everything  in one screen only allow eyes to "scroll", instead of hands + short term memory.
Here's the drill:

That way, blokes like me, have an option to "scroll", or "download" [since the attachment remains, even after embedding the image].  Providing that option incurs no more deficit than a little more work for you, and a little less for the kind folks that attempt to assist you.

And I fixed that link -- so, if my terse explanation didn't do it, then try the link [again] -- also, you could have Googled it -- I mean if you were really determined ;)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 03:50 pm
I dug this out of my archives.  This is a version of the Joule Thief that I came up with a while back, and I think I even got it working.  It's a bit more efficient:

(http://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=259569)

Notes:



And, here's your diagram, again:
(http://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=259548)

I'm not sure what you're trying to achieve with that Zener on the Base of the transistor.  The forward voltage drop across the Base-Emitter, will never allow that voltage to rise any higher than around 0.7V, so the Zener will have no effect, unless it's to protect the transistor from reverse voltages, and I've never seen the need.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: TomGeorge on May 27, 2018, 03:53 pm
Hi,
How much POWER are you going to get out of your Savonius (vertical axis) wind turbine?
Can you post its specs/data, and/or a picture please.

For flea power systems the Joule Thief works well, you may have to check how reliably it starts with slow power level changes.
The Joule Thief is basically an oscillator, so to start, it may need a proper step ON to reliably function.
You will need to experiment to check it suitability.

Interesting project.

Tom... :)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 04:42 pm
For the Savonius I  only have a concept at this time. Plan is to make a 4 wings one (to balance), for some 1 m high.

How to transmit force from the rotor to the generator - still to be decided.

One plan is to directly glue the generator's axis to the turbine axis. Another plan is to use friction wheels. The point in any transmision is that I will loose power no matter what. But I need some velocity to milk the rotor, which I suspect will be difficult ot obtain directly from the Savonius rotor. 

++++

Initially, I wanted to use PC fans and replace the wings by some longer profiles. When I went to the field, I found out there is very slow wind (forested area).  Most likely, a propeller turbine would have no enough wind to move.

This is a demo project. It is to prove that wind can generate electricity and to show how it works. Efficiency or economic aspects are not important, for the time being.

During internet search I came across various other Joule thief circuits. But the main problem for all is that there is very little info (if any) of whether those circuits were ever moved from the screen to the real life. I do not know whether they work or not.

As a result, I made my mind to make it as simple as possible, and therefore I picked the circuits with less components. One of them is the one I posted, but I do have a few more (main criteria are:  not to use more than 2 transistors and no integrated circuit or modules).
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: jremington on May 27, 2018, 05:17 pm
Quote
It is to prove that wind can generate electricity and to show how it works
Is there someone on this planet, above the age of 5, that doesn't already know this?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 05:34 pm
@ jremington

Try to explain how wind can generate electricity to a 12 years old kid. 

Or just answer to yourself: why planes fly?


Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 05:37 pm
Is there someone on this planet, above the age of 5, that doesn't already know this?
Have you never heard of a Science Fair project [for example]?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 05:42 pm
Here it is a even simpler Joule Thief circuit.

The point in the charger I try to build is to get voltage above 4.5 V to charge my 3 NiMH units.

And to do this out a Savonius that can offer the most - 3 V (in happy situations).

Using only few components and no module.

The challenge it to have it working.

:-).

https://forum.arduino.cc/Themes/default/images/post/clip.png

https://forum.arduino.cc/Themes/default/images/post/clip.png (https://forum.arduino.cc/Themes/default/images/post/clip.png)(https://forum.arduino.cc/Themes/default/images/post/clip.png)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 05:44 pm
https://forum.arduino.cc/Themes/default/images/post/clip.png (https://forum.arduino.cc/Themes/default/images/post/clip.png)(https://forum.arduino.cc/Themes/default/images/post/clip.png)

(https://forum.arduino.cc/Themes/default/images/post/clip.png)

https://forum.arduino.cc/Themes/default/images/post/clip.png

The image does not show up. I inserted the link to the URL of the image - nothing. I have no idea what to do then. :-(((((
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 07:05 pm
The image does not show up. I inserted the link to the URL of the image - nothing. I have no idea what to do then. :-(((((
To the following thread:

http://forum.arduino.cc/index.php?topic=364156.msg3749026#msg3749026 (http://forum.arduino.cc/index.php?topic=364156.msg3749026#msg3749026)

I added a more comprehensive tutorial than any other I could find on that thread.  Have a look at it [Post #74].  Hopefully that will help you understand how this is done ;)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 07:18 pm
"This site can't be reached
%22's server IP address could not be found."

When I go to the "insert image" the only window I see is the one for the URL. Nothing else.

I am on Windows7 64b.

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 27, 2018, 07:57 pm
"This site can't be reached
%22's server IP address could not be found."

When I go to the "insert image" the only window I see is the one for the URL. Nothing else.

I am on Windows7 64b.
Yup.  I caught that, but obviously not quick enough ;)  Try the link again, it should be working, now.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 27, 2018, 08:47 pm
I am trying again.

(https://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=259622)

I have no idea why it did not work first time. Just do not understand.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: allanhurst on May 27, 2018, 11:28 pm
Quote
For the Savonius I  only have a concept at this time.
The most important device here is likely to be the generator. Using an off-the shelf cheap dc motor is unlikely to be the best solution.

Consider winding your own pm alternator?

Until you know what your generator produces, discussion of various possible power conditioning techniques is academic at best.


Alan
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: mauried on May 28, 2018, 12:43 am
Have you actually built the wind turbine ?
Savonius rotors are very inefficient, and if you are trying to generate anything at very low wind speeds, the type of generator is most important, as it requires extremely low rotational friction.
Id start by building the turbine first, and then worry about getting useful power from it.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 28, 2018, 07:00 am
This is a demo project.

Any little power is sufficient.

If nothing else works, then I will use a fan to move the Savonius rotor (I must do this indoor anyway). Or even blowing on it. :-)).   
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 28, 2018, 07:03 am
Note about my post #17:  Uploading the picture to show up within the text did not work first time. 

I did not experiment the posted circuit in post #17. 
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 28, 2018, 07:38 am
Note about my post #17:  Uploading the picture to show up within the text did not work first time.  

I did not experiment the posted circuit in post #17.  
Do you mean post #18?  If you are referring to the diagram in that post, it's the "classic" Joule Thief circuit.  It's pretty easy to get that working.  But, it's critical to get the coil hooked up correctly.  I suggest adding a capacitor across the generator [following the power switch].  The value will depend on what kind of power is involved.  Such a capacitor will make it more likely that charge will accumulate and run the stored voltage up until the Joule Thief starts to oscillate.  Then, it will transfer power from the capacitor, to the battery.  But, as pointed out before, this will only be feasible for a low power system.  But, it sounds like that's what you are after -- merely a demonstration of principle.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 28, 2018, 08:45 am
@reversEMF - right!

I only want to show that this way of obtaining energy is feasible using basic resources, it is easy to make, easy to maintain.

[maybe  OT: so many times I saw projects (including my projects :-)) never getting to an end because of to ambitious goals. It is crystal clear in my mind that Arduino is about learning and teaching in the first place. Of course, real life projects can be done in the Arduino ecosystem (or alike), but myself I am not in this.]

Thank you for the reccomandation! It is possible to use a trimer (aka variable capacitor) for the capacitor you suggested? If so, what value do you think? 

I can find here easy a 4-20 pF and a 7-100 pF.

The 7-100 pF has a larger range so might be handy. Then I can go (hopefully :-) ) by trial and error.

The coil- yeah, I have a bunch of torroids and drossels on my desk. I cant measure them by my multimeters and honestly the devices to measure capacitance and inductance are insanely expensive.

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 28, 2018, 05:23 pm
Please the "Quote" feature.  Otherwise, it's hard to track context when reading your posts.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 28, 2018, 05:43 pm
@ ReverseEMF - you are right!

But so far, I couldnt figure out how to quote part of the text. Quote command is picking all text, making everything even more difficult to read. I attempted to delete unwanted text or to manually quote, but the result was even more fuzzy :-(.
I will be very happy if somebody can point me to a tutorial or just tell me how to do.

++++

This is my lucky thread - I already figured out how to insert images in the text! :-))
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: TomGeorge on May 29, 2018, 12:25 am
Hi,
If you look at the tool bar across the top of the post/edit window, you will find an icon that shows "Insert a quote"
This inserts quote tags around a highlighted bit of text in your post window.

So copy and paste what you want in your post, then highlght it, then select "Remove Formatting" in the tool box, the "Ao" icon.
Then select "Insert a Quote".
You will then have your tect in a quote box.

It is worthwhile using "Remove Formatting" to take out any artifacts that the editor may misinterpret.

http://forum.arduino.cc/index.php/topic,148850.0.html (http://forum.arduino.cc/index.php/topic,148850.0.html)
is a good read.

Tom... :)

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on May 29, 2018, 05:07 am
@TomGeorge
Quote
So copy and paste what you want in your post, then highlght it, then select "Remove Formatting" in the tool box, the "Ao" icon.
Then select "Insert a Quote"
Thank you!

My mistake was:  I selected and quoted the text directly in the quoted text, in the author's post.

PS It is any way to also automatically quote the quoted author in the same time? Thanks!
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on May 29, 2018, 07:38 am
PS It is any way to also automatically quote the quoted author in the same time? Thanks!
Try this:
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 04, 2018, 01:43 pm
Perhaps is not exactly the right place to rise this up, but I hope I will be forgiven.

There is very little - if any - info about vertical axis turbines in a manner that is appropriate for demo or diy aim.

I noticed so far two main issues with vertical axis wind turbines:

a) the available voltage is going to be far less than one of a PV panel, at a similar phisical magnitude

Perhaps this comes from the PV being industrially manufactured while turbines have to be made from scratch in most dit cases => this leads me to the idea to use a "buffer" - like a super-capacitor and then periodically discharge it through the Joule thief circuit, but under higher voltage - that is something I never saw in the internet and I would be very glad to get your opinion


b) There is a dependence of the Joule circuit to the way the inductance is made or mounted. I have no idea how to approach this, except by trial and error - any tip or no-matter-how-personal opinion would be of great help.


For the time being I am working on the PV module, but I will finish very soon and start the fight with the electronic part of this wind turbine.

The plan is to use an (close to) exhausted 1.5 V AA Alkaline pile in place of the wind turbine while desk prototyping. Alternatively, I can mount a voltage divider to the NiMH 3 or 1 units that I already coupled to the PV generator.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 16, 2018, 08:23 pm
I built the simple Joule thief.

Parts:
- Transistor : 2N2309 - 1 pc
- Rezistor: 1 K/ 0.5 W - 1 pc
- LED: white, 5 mm - 1 pc
- torroid core, 1 cm diameter, white ferrite - 1 pc
- cables- 0.5 mm D: 2 pcs @ 30 cm each, blue and white
- minibreadboard - 1 pc
- Battery NiMH  AAA, 1.2V - 1 pc (alternatively: pile AA, exhausted)

Now it comes the strange part: a slightly larger blue torroid core, of 2 cm D, 80 cm wrap same wires did not work. I went down to 40 cm wraps - no chance LED did not light.

In one example it was a picture of a blue ferrite ring - looking quite the same I used and did not work.

Searching for ferrite cores I found tons of info about a zilion types of ferrite rings but nothing clear about what the colors mean. Somewhere I found that some types have more permeability than the others, which sounds somehow trivial.

Supposing I will end up with a suitable more efficient circuit, then how I can be sure I  can order the same type of ferrite cores?

Thank you very much for any tip, kind guidance or pointing to a more friendly web-site!


 
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: allanhurst on Jun 16, 2018, 08:33 pm
Quote
Somewhere I found that some types have more permeability than the others, which sounds pretty trivial.
Absolutely not!

The permeability, loss vs frequency , saturation magnetising force etc vary enormously with different materials.

Unless you know these characteristics you can't design the inductor.

I don't know the colour codes for various ferrite materials - where did you get the cores  from? does the manufacturer publish data which would help?

Allan.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 16, 2018, 08:53 pm
@Allan

I fully agree.

The seller knows nothing more than the size and the color.

The Joule thief is a demo, so no critical parameters.

But still, how can I order the same ferrite cores from some other seller or from the same seller later on, if they cant tell me more than the above?

It would be wonderful to differentiate by color, at a minimum. But would that suffice?


+++

An alternative might be to use transformers in place of the torroids or to find somewhere a circuit using linear inductance. I would avoid that since it will certainly lead to  more complex circuits.

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 01:07 am
I am trying again.



(https://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=259622)

I have no idea why it did not work first time. Just do not understand.

Do you know what the black dots mean, they are more important than core type/permeability ?
They mark beginning of the winding, I think you connect wires not correctly.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 01:16 am
This is you turbine
https://www.newphysicist.com/make-vertical-axis-wind-turbine/ (https://www.newphysicist.com/make-vertical-axis-wind-turbine/)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on Jun 17, 2018, 02:16 am
Yes, I've gotten away with just using toroids designed to be used as RFI filters, when making Joule Thiefs.  I know very little about designing inductors, and I've had little problem getting Joule Thiefs to "work".  Do they run at optimal efficiency?  Who knows.  When I'm doing this stuff, I'm in full-on hobbyist mode  :)


So, like Ted said, you probably didn't get the wiring right.  Just switch the wires on the primary, and try it again [or on the secondary].  I.e., make sure it's hooked up like the diagram Ted posted.  Also, I've found it seems to work best when the turns ratio is 1:1.  Example: if there are 10 turns on the Primary, then make sure there are 10 turns on the Secondary.

Also, it helps if the toroid is meant to to be used for RFI filters with a max current flow greater than the kind of current the Joule THief will be running at. If it's just driving a simple White LED, then we're talking around 20 to 30mA.  Also, the toroid should be able to support frequencies up to a few MHz.

Now, I'm sure my more inductor savvy piers are going to jump all over me [and go ahead], but I'm just trying to give you "seat of the pants" hobbyist pointers [you know, like, "hey, this toroid that I bought from Electronic Goldmine [with no discernable parameters other than it's for making RFI filters] looks big enough for this application, lets give it a try!"
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 06:34 am
I wrap the 2 wires (blue and white) together, in the same way in the case of white ferrite and blue ferrite.

I connected the white wire of one side to the blue wire from the other side - this is the common end. Then I used the remaining wires to connect to the circuit as in the schematics.

I unwrapped and wrapped again starting opposite direction. I used grey ferrite core. I switched the ends. No way. Silent LED.

One moment I thought there is very low inductance in blue ferrite (for unknown reasons), so perhaps more winding would help.

***

The method is here (but it is detailed in many other web-sites)

https://www.evilmadscientist.com/2007/weekend-projects-with-bre-pettis-make-a-joule-thief/ (https://www.evilmadscientist.com/2007/weekend-projects-with-bre-pettis-make-a-joule-thief/)

and a more kids friendly desccription here:

http://technologytutor.co.nz/technology-and-science-for-kids/01-build-your-own-joule-thief (http://technologytutor.co.nz/technology-and-science-for-kids/01-build-your-own-joule-thief)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 06:44 am
Show the picture
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 07:28 am
Here it is the pic:

(https://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=262554)
- background: the circuit which works ok
- grey ferrite ring - which does not work (wired)
- blue ferrite ring which does not work

The length of the wires in blue and grey cases were 80 cm and then 40 cm.

The length of the wires in the white ferrite ring 30 cm.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 07:33 am
Add 1uF capacitor parallel to resistor
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 07:43 am
@Ted

Thank you for pointing me to the tutorial!

It is about a fixed H-rotor (giromill). Effective in high speed wind and the pitch can be modified automatically with the wind-speed. Some designs cant ensure starting on its own in low speed wind.

The person in the video used a direct coupling to the generator, which can be beneficial in terms of efficiency when winds  are high-speed.

The interesting point is how the author shaped the wings to mimick an aerodynamic foil.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 07:44 am
Can I use a 4.7 uF cap?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 07:52 am
Can I use a 4.7 uF cap?
ok
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 08:57 am
@ted - genial idea! Thank you very much!

My 4.7 uF cap got lost. So I use a 10 uF cap.

Mysteriously, the LED lighted! (she happy, me happy :-)). Using both the white ferrite ring and the blue ferrite ring.

With the cap, the white ferrite circuit seems to be less brightly than without the cap.

I didnt measure the current in both cases (with cap and without cap), so maybe is just an illusion.

+++

Ok with the classical and simple Joule thief, magnetic field etc. I can explain that, first to myself.

But I cant figure out what the cap does in this case. My first thought is that it changes the frequency to fit what the transistor can commute. But I maybe wrong.
 
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 11:27 am
Phase two: generator.

Firs fail: the toys motors cant supply the current I need to light the LED in the Jule thief  circuitry I made.

I mounted a small propeller on a 3V motor and blow it by a hairdryer (a big one, really). Although the propeller spins very rapidly, like in the case of the motor being feed by energy, the LED did not light.

By multimeter to motor, the current supplied was up when the motor starts and stops - which I suppose has something to do with current pulse /induction.

I could not reproduce this behavior with the LED, however.

+++

Next attempt: PC fans. I shall check when I will find the fans I brought in my closet.
:-((.

A more sophisticated attempt in plan: brushless motors. Using my dear Shotkeys to get DC. :-).
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 01:45 pm
But I cant figure out what the cap does in this case. My first thought is that it changes the frequency to fit what the transistor can commute. But I maybe wrong.
 
1k resistance for AC  is reduced to ohms.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 01:51 pm
Phase two: generator.

Firs fail: the toys motors cant supply the current I need to light the LED in the Jule thief  circuitry I made.

Capacitor 10uF to motor terminals may help, why you not connecting  LED directly to motor ?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 04:19 pm
I will mount a 10 uF to the motor.

Few months ago, a friend of mine mounted an white led to a PC fan. It lighted.

The wind turbine is part of the combined generator, that includes the PV charger (separate thread) and perhaps an energy harvesting module in a later stage.

Therefore, the wind, the Sun etc. will all charge the same battery. And the battery will supply current to the LED.

Modular design. :-)



Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 04:52 pm
I will mount a 10 uF to the motor.

Few months ago, a friend of mine mounted an white led to a PC fan. It lighted.
That is my question in post # 46.
If LED is not lighting reverse connection of it.
Basically any motor with magnet should work
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 05:23 pm
I reversed the connections of the toy motor with no result. Maybe I shall check the wiring, connections again.

Ill check mounting the LED directly to the motor, to "debug" :-)).

The motor my friend used was a PC fan one, which is far lower rpm than a toys motor.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 06:59 pm
I randomly pick up a few motors and speed them quickly by hands, and the LED is always lighting, if is not I change  rotation  direction.
Jule thief  required pure DC, from motor you don't have that.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 07:39 pm
Then I have to make sure I get a pure DC from my generator.

Maybe using the same concept of Shotky + Zener as in the case of Photovoltaic charger? But the problem is now how to regulate 1 V, in absence of this value in the Zeners range.

And is also more problematic because the available power is much less than in the PV case, I dont like to throw current away.

I came across LT3022, which is manufactured by Analog, which is stated to regulate as low as few hunderd miliV. Looks interesting, although not in line with my "simple design" rule.


http://www.analog.com/en/products/power-management/ldo-linear-regulators/positive-linear-regulators/lt3022.html#product-overview (http://www.analog.com/en/products/power-management/ldo-linear-regulators/positive-linear-regulators/lt3022.html#product-overview)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 17, 2018, 08:26 pm
Another interesting idea is to use a supercapacitor. Then the motor will charge the supercap and the supercap will charge the battery via Joule thief- in order to reach the required voltage to charge the NiMH (or LiIon).

A nice point in this approach is that I can charge the capacitor during night and discharge it daytime. Or using 2 of them, each for 12 hours.

+++

I searched the internet about supercaps as chargers but no result so far.

I suppose no matter the voltage (usually 1-3 V, very variable), the cap will charge anyway. Then the problem is how to gradually discharge the supercap into the battery.

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 17, 2018, 11:13 pm
How about not to use Joule thief, battery will be charged without it ?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: mauried on Jun 18, 2018, 03:18 am
OP really needs to look at the physics of what they are trying to achieve.
Small DC motors simply wont work for this kind of application as they are designed to spin
really fast, usually in the thousands of RPM, and a vertical vane wind turbine will simply not spin this fast, no matter what.
You will be lucky to get a few hundred RPM from one .
Small wind turbines use a special type of alternator, usually a 3 phase permanent magnet type with very strong Niobium magnets to get a sufficiently high magnetic field to allow the turbine to produce usable voltages at low RPM.
Do some research on small vertical vane wind turbines and the types of generators they use.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 18, 2018, 04:24 am
Motor like this gives 2.5V @ 500 rpm ( speed of my drill)
(http://img.hisupplier.com/var/userImages/2014-01/09/151114403_240.jpg)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 18, 2018, 06:40 am
@ted

I am not a fan of Joule thief :-).

I did not find any other simple circuit (on other words - no integrated circuits) to rise the voltage from some 1V to more than 3V. 

@Mauried

This is a demo project. Efficiency is far less important than simplicity.

I am considering a brushless motor.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: mauried on Jun 18, 2018, 08:32 am
The issue isnt efficiency.
Its all about getting sufficient volts from your motor at the speed the turbine will turn it.
You need to calculate or measure how fast the turbine is going to spin via whatever method you use to spin it , and then source a motor that will provide sufficient volts to light your led at this speed .

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 18, 2018, 11:17 am
From this motor at high speed I have 12V - post # 55
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 18, 2018, 12:14 pm
How pure is "pure"?

When I spin my motor I increase the speed in few seconds, keep the hair dryer at (relatively) constant distance to the motor's propeller for few seconds and then turn the dryer off.

I think in real life that might be some wind bursts but the reason why I choose the vertical axis turbine is exactly the fact that in the target area the wind speed is usually 1-2 m/s.

It is something confuse in all this. Why the Joule thief cant work on variable voltage? Or, at least, how much variability is OK?

If I mount a capacitor (as advised) to the motor, then some sort of equilibrum between the current sent to cap and the current sent to Joule could be achieved. That is my understanding, but I may be wrong.

A joule thief can offer higher voltage even when closing and opening the circuit by a push button. Why  it cant do the same when the voltage varies with the wind speed?


@mauried

Think to the project as a sort of "close garage challenge": I have only usual components: a handful of diodes and transistors, resistors, wires.  That is fun and is also learning.

I have a toy motor in my hand. No Hall sensor or similar. How can I measure the spinning speed? We have to imagine a method. What I have in mind is to place two wires ringshape near two sides of the motor and measure the current by an multimeter. Or use some sort of optical method. Lets be innovative and imaginative.

Good engineering is simple engineering. Exceptional engineering is fun engineering. :-)

 

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 18, 2018, 12:35 pm
To answer your question you need to look at oscilloscope, If motor capacitor does not help you need a bigger motor.

 try bigger   capacitor.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 18, 2018, 01:00 pm
OK, I will mount my (portable) ossciloscope to motor terminals (cap added) and  spin the rotor by hair dryer.

I also got my brushless motor today. But I need to make a circuit (6 Schottkys is the simpliest I could find) to milk DC out if it, as far as I know. 
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 18, 2018, 01:13 pm
Make a picture what you see on oscilloscope.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on Jun 18, 2018, 06:24 pm
Here it is the pic:

(https://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=262554)
- background: the circuit which works ok
- grey ferrite ring - which does not work (wired)
- blue ferrite ring which does not work

The length of the wires in blue and grey cases were 80 cm and then 40 cm.

The length of the wires in the white ferrite ring 30 cm.
You might have better luck with magnet wire, and with smaller toroids [so the windings are closer together, and more compact]. 

Also, [referring to another post] on those motors/generators you said "don't work", did you attach a meter to them to see if they are outputting anything [and whether your getting AC or DC]?

And whenever you say "it didn't work", I think, what does that mean.  Why do I think that? Because, I don't know for sure if your aware of the concept of "a multitude of variables".  It would be more informative if, instead of saying "doesn't work", you told us what the "failure mode" is.  Even if it seems obvious or redundant.  For instance, when you were trying the various cores [toroids], did you just hook it up, then decide it wasn't working if the LED didn't glow, or did you try reversing the wires on the primary [or secondary] to give it another try...then, even after that, did you check to make sure the power source was adequate/functioning/consistent -- i.e. with the goal of limiting variables as much as possible.  And, in case you don't know what I mean by variables: The power source is a variable [in fact power source voltage is a variable, power source consistency is a variable, power source current capability is a variable], proper inductor hookup is a variable, LED polarity is a variable [i.e. is the LED connected properly].  If any if these variables are not consistent -- if more than one fail at a time, and if those failures are not consistent, then you can easily be misled.

One example of limiting variables is to use a Bench Power Supply when doing something like, testing Toroid Cores to see if they "work" or not.  A bench power supply is far more likely to be consistent, than, say, a motor being used as a generator.  Test the toroids with the bench supply, with parameters set to as closely model the real world power source [whatever that winds up being], as possible, then, when you have a set of cores that worked with the Bench Supply, you can have more confidence that if, when you try them with the real world power source, when they fail, it has more to do with the real world source. 

Another example: when trying different power sources, use the same Joule Thief setup, each time.

If you try to "save time" by testing a bunch of things at once, when things don't work, it's hard to be sure what the source of the failure is.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 18, 2018, 08:28 pm
@ReverseEMF

Thank you! You are right!

I guess is the time to plug in my power supply and to use a more consistent vocabulary to a more detailed description.

 
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 18, 2018, 09:08 pm
Unfortunately, the OlyMEGA forum is currently down for upgrades. I took apart a bunch of old CFLs and scavenged toroids out of them, and wrote up with pictures how to properly phase the coils.

The dots are for transformer phasing. With a bifilar winding such as you have there (ie, the two wires are twisted together), the matching ends will have the dots on them. Basically, when an AC signal is on the positive half going in, the same end of the secondary will also be on the positive half.

From your picture, you have the windings connected correctly.

http://slideplayer.com/slide/236620/ (http://slideplayer.com/slide/236620/)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 18, 2018, 09:09 pm
BTW, toroids meant for reducing RFI are intentionally very lossy.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 18, 2018, 09:59 pm
intentionally very lossy.
How come ?
The idea of the toroid is keep energy inside = no energy transmitting out, compare to ferrite rod.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 18, 2018, 11:30 pm
Ferrites meant to prevent or reduce RFI do a better job if they absorb RF energy.

Also, if it isn't lossy, the inductor formed by this will resonate at some frequencies, not a good thing if you are trying to reduce RFI. The lossy ferrite core decreases resonant peaks

I should say that NOT ALL ferrite beads and toroids for reducing RFI are lossy, but many are.

https://www.allaboutcircuits.com/technical-articles/clean-power-for-every-ic-part-3-understanding-ferrite-beads/ (https://www.allaboutcircuits.com/technical-articles/clean-power-for-every-ic-part-3-understanding-ferrite-beads/)

Quote
Noise In, Heat Out
Recall that ideal inductors and capacitors do not dissipate any energy; they merely store energy, either in a magnetic field (inductors) or an electric field (capacitors). A resistor, on the other hand, takes energy out of the circuit and dissipates it as heat. Ferrite beads, unlike inductors, are intentionally resistive at high frequencies. This is why the above plot has the red dotted line labeled "R"--from about 100 MHz to 1 GHz, the bead exhibits significant resistive impedance, not reactive impedance. Actually, some ferrite beads and ferrite-core inductors are almost identical in construction, except that the ferrite bead uses a more "lossy" ferrite material because the manufacturer wants the bead to dissipate rather than store high-frequency energy.

But why belabor this point? We belabor for two reasons. First, you cannot truly understand a ferrite bead until you have adequately pondered this fundamental distinction between an inductor and a bead. Second, this "lossy" characteristic makes the ferrite bead especially suitable for noise suppression. Why? Inductance can lead to resonance and ringing when high-frequency noise energy stored in the inductor interacts with capacitance elsewhere in the circuit. As we saw in the previous articles, ringing can become seriously problematic even when we are dealing only with parasitic inductance. We don't want to exacerbate the resonance/ringing situation, and thus we opt for ferrite beads over inductors.
(https://www.allaboutcircuits.com/uploads/articles/CP3_Wurth_bead_response.JPG)

Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 18, 2018, 11:32 pm
https://incompliancemag.com/article/all-ferrite-beads-are-not-created-equal-understanding-the-importance-of-ferrite-bead-material-behavior/ (https://incompliancemag.com/article/all-ferrite-beads-are-not-created-equal-understanding-the-importance-of-ferrite-bead-material-behavior/)

Quote
Another way to look at this is in terms of what the part is actually doing while in its inductive and resistive stages. Like other applications where there is an impedance mismatch with inductors, part of the introduced signal is reflected back to the source. This can provide some protection for sensitive devices on the other side of the ferrite bead, but also introduces an "L" into the circuitry and this can cause resonances and oscillations (ringing). So when the bead is still inductive in nature, part of the noise energy will be reflected and some percentage will pass through, depending on the inductance and impedance values.

When the ferrite bead is in its resistive stage, the component behaves, as stated, like a resistor and therefore impedes the noise energy and absorbs this energy from the circuit and does so in the form of heat. Though constructed in an identical manner as some inductors, using the same processes, manufacturing lines and techniques, machinery and some of the same component materials, the ferrite bead uses a lossy ferrite material while an inductor utilizes a lower loss ferrite material. This is shown in curves of Figure 2.

(https://incompliancemag.com/wp-content/uploads/2010/08/1008_F2_fig2.png)
1008_F2_fig2

Figure 2: Reflection vs. Absorption

This figure shows [μ''] which is used to reflect the behavior of the lossy ferrite bead material.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ted on Jun 19, 2018, 12:12 am
@polymorph

Thanks for this info, I never consider that.
Where I can find similar info to compare totoid with rods ?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: allanhurst on Jun 19, 2018, 12:19 am
Just curious......

where do arduinos come into all this?

Allan
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 19, 2018, 07:30 am
@Allanhurst

The project consists in:

a) Photovoltaic charger - see separate thread - completed
b) Wind turbine charger -  this thread - ongoing
c) Lighting system - simplified version so far - no thread foreseen
d) Control system - under preparation by providing control points in each of the components above (a, b,c). - no thread by now.

The d) - control system - is where the Arduinos come in.

Step by step :-))

+++

[OT maybe: I love to understand what I am doing, even in the simpliest cases. See the Joule thief circuit- everywhere is given as a "simple thing to make". Yes, but is not as simple to understand. I hate "monkey see monkey do" :-)))]


Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 19, 2018, 08:45 pm
Where I can find similar info to compare totoid with rods ?
From the manufacturer of them. No one but them can say exactly what is in a given ferrite toroid or rod but the manufacturer.

You can get some idea if you have an LCR meter. Wind 10 turns on it, measure the inductance. Knowing that for a toroid, the inductance is proportional to the square of the number of turns, you now know how to calculate the number of turns to get a given inductance.

IMO, a joule thief is not a good choice for this. Who knows how efficient it will be? Likely not very efficient. There are chips custom made for this sort of thing.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 19, 2018, 09:50 pm
Simplicity is more important than efficiency, because the project is a demo for kids.

And is a nice way to learn. :-).
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: polymorph on Jun 19, 2018, 11:11 pm
Except those specialized ICs have stable, known characteristics.

http://www.ti.com/product/TPS61322 (http://www.ti.com/product/TPS61322)

Just sayin'.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: ReverseEMF on Jun 21, 2018, 08:40 am
FYI: I've used the following to make Joule Thiefs -- but they are SMD parts, so may be hard to solder too.  Perhaps you can make a breakout board for one, or both of these:

https://www.mouser.com/ProductDetail/704-DRQ73-330-R (https://www.mouser.com/ProductDetail/704-DRQ73-330-R)
https://www.mouser.com/ProductDetail/652-SRF0703-330M (https://www.mouser.com/ProductDetail/652-SRF0703-330M)
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 23, 2018, 11:35 am
Under controlled voltage (bench supply source):

Small  13x7x5 mm ferite ring: starts lighting at:
- without capacitor: - 0.85 V
- With capacitor 10 uF : 0,83 V
- Adding 47 uF to existing 10 uf, in parallel  -> the led dimmed and started blinking!

With the capacitor, at the same value of voltage, the LED is brighter.

The source displayed current of 0 - 0,002 A, changing every second.


(https://forum.arduino.cc/index.php?action=dlattach;topic=549808.0;attach=263338)


Certainly, the capacitor helps by lowering the supplied voltage to which the LED opens and to providing more current.

There is also a clear link between the capacitance, the inductance and the rise in the voltage to the LED pins.

Because the values of the parameters are close to the source and multimeter accuracy, I cant fine tune the voltage - in the range of 0.001 V.

The practical consequence of these findings is that there is a value of the capacitor that grants best efficiency of the circuit. But how to calculate?
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 23, 2018, 11:38 am
@polymorph

It is nice to have a plan B, thank you!

@ReverseEMF

Thanks for pointing me to the commercial names and look of the coupled inductances!

My attempts to find them here were not successful do far, because of vendors having no idea from my description what I was looking for :-(.
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 23, 2018, 12:07 pm
A.

Changing the ferrite ring by a larger one - 20 mm diameter:

- using 47 uF the LED is brighter than using 10 uF.
- The voltage from which the LED started to light was 0.82 V, while the current was stable at 0.002A (sources shows).

I guess I can confirm then that the value of the capacitor that makes the circuit able to light the white LED is in close relation with the value of the ferrite inductance.

I also believe (but I have no evidence) that some circuits still rise the voltage without a capacitor because the (implicit) capacitance of the circuit is enough to keep the oscillations, at lower values of inductance.

B.

I mounted both ferrite rings (the 13 mm one and the 20 mm one) in parrallel, with the 47 uF capacitor on. The LED started to light at 2.15 V.

For the time being I cant measure the inductance and the vendor has no clue about DS of the ferite rings :-(.

C.
Late edit: once the circuit is on and the LED lights, at about 0.85 V, then decreasing the voltage to 0.56 dims the LED but it still brights.

D.
Later edit: the 1 uF capacitor turns the LED on from 0.56 V (as the source displays).
Title: Re: Wind turbine Savonious Charger based on Joule Thief - advise for a charger?
Post by: falexandru on Jun 24, 2018, 02:09 pm
I opened another thread that combines this one and the one related to solar charger, because these two will work together. 

The discussion may continue in that combined thread, in the same section (General Electronics) of the forums.

Thank you!