Charge a battery with pc fans?

[Billalo]

Hello everyone!

I've been going through this for a few days forum and I never have enough !!
I have already learned a lot of tips on "active" econology and I am proud of it !!

Reading some posts, I had the following idea: Create a generator to recharge a buffer battery using several pc fans.

Why pc fans? Because it's cheap, easy to find, all done and the generator is integrated (DC motor?)

Obviously, the surface to the wind is very small, so I have the idea to design a kind of funnel which would serve to increase the surface of "capture" of the wind and also to increase the speed of the wind during the decrease of the diameter. (unless it creates too much resistance?)

First question: Can we really create a current by turning the blades of a fan like this?

Second question: If yes, can we put several generators in series-parallel to obtain the desired currents and voltage? (I don't see what prevents but hey ...)

The voltage regulation-stabilization system for the load should not be too much of a problem apart from this:

Third question: What is the voltage to be applied to a lead-acid battery to recharge it knowing that it is approx. 12.6V. fully charged?

I want to make it clear that performance interests me much less than the experience of such a project. However it would be nice to combine the two!

I look forward to your comments and feedback!
Thank you very much.

[loop]

Good evening Billalo

I do not know specifically the type of motor that equips PC fans but they are probably very small and of the CC type with permanent magnets, 24 V voltage (?)
So a priori, they can turn into a generator if we make them run
But beware, their nominal speed must be quite high
Perhaps the simplest is to experiment directly
Get a voltmeter and measure the voltage across the fan motor when you blow it
This will give you an idea of ​​the features

For the funnel effect, this may seem like a good idea, but the air always tends to want to flow where it meets the least resistance, so next to obstacles
Nevertheless, the air currents in the dwellings clearly reflect the pressure differences that can exist between two façades, one in the wind and the other in the wind.

The subject of the multi helix generator has been treated with a subject on an existing product, I will try to find it

To charge a battery, 13.5V is fine but you must anyway respect the 10% rule for a lead-acid battery
For example a 10 AH battery must not be charged with an intensity greater than 1 A
Do not forget the anti-return diodes so that the charge is done only in the desired direction, i.e. generator-> battery

Good luck

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[loop]

Here is the link on the subject of microturbines

https://www.econologie.com/forums/micro-turb ... t4195.html

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[Billalo]

Thank you for all your looping answers!
You still answer a lot of my questions, and your opinion encourages me even more.

I will continue my research on the subject through the net and others ... and maybe I will have time to find my old multimeter and a (not too) old fan ...

Do you know a site that explains simply and through mathematical processes the characteristics of winds, fluids, and everything that can come close to it? I am completely new to the subject.

I will not hesitate to share my progress with you.
Do not hesitate to criticize my project. All opinions are welcome.

Thank you very much.

[Christophe]

Mmmm if I'm not mistaken someone had already proposed exactly the same idea on the forum. We should find the subject in question ...

If I remember correctly we had concluded (I had not followed very well) that the design of the "vanes" of the PC ventillo does not give them the best performance to "capture" energy ....

[Billalo]

If I remember correctly we had concluded (I had not followed very well) that the design of the "vanes" of the PC ventillo does not give them the best performance to "capture" energy ....

However, the design of the fans is made to expel the air as well as possible ...
So this is not reversible? I would have thought, however ...

When you blow on it without forcing, it turns however very easily ... But it is true that the speed is not can be sufficient to create a significant current ...

[Christophe]

The best performance is obtained by the shapes of airplane propellers, helicopter blades and finally wind turbine blades (derived from helicopters) ... all are quite similar ... it's no coincidence.

On the other hand, their shape is far from the "concave vanes" of pc fans ... I would say that what is required with a pc fan is:
- optimum flow / congestion ratio
- noise / flow reduction (well in theory ... )

Running idle and creating engine torque is not the same ...
Put a slight brake on your test fan and you will see that it does not turn out so well that it ...

But I think the interest of this idea is to be able to make small wind turbines really cheap with gear recovery ... but do not expect interesting powers ... a few W per fan ...

[Billalo]

I do not expect of course huge powers but about 2.5W per fan. But the most important here is the maximum current (under 12 or 24Vdc) useful to recharge the battery in the least possible time.

The pc fan never runs "empty" since the motor (the generator) is incorporated, right? I don't quite understand what the additional brake would be.

The principle is obviously to use recovery equipment or at low cost!

[Christophe]

The pc fan never runs "empty" since the motor (the generator) is incorporated, right? I don't quite understand what the additional brake would be.

Certainly but if there is no demand for current and therefore torque, it is as if it were empty .... right?

I think you did your tests by blowing on it without putting an electric charge if?

[loop]

Hello

The reference site for self-built wind turbines is:

www.mini-eoles.com

It contains all the info on recovering small motors from generators
For the question of the blades, it is necessary to know that a driving propeller (plane type or ventilo) is reversed compared to a generating propeller (wind turbine)
On small dimensions it is not too annoying because the yield is not sought

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