Need help for Peltier modules

[Gaston]

I made a second prototype. I went up to 15.5 volts with 8 modules.
By cons I always have an intensity of 0.08A.
Please answer this question.
How to find modules that produce more intensity?

It is not a module problem, but a load problem.
For example, putting a short circuit at the output, you might get 2 or 10 A, but with 0V ...

The theory is simple: to obtain the maximum power the load must have an impedance equal to that of the generator ... which varies according to hot and cold temperatures.
The load must be constantly adapted to the operating point.
The equivalent of what MPPT do in the case of photovoltaics.

[johan07]

I made a second prototype. I went up to 15.5 volts with 8 modules.
By cons I always have an intensity of 0.08A.
Please answer this question.
How to find modules that produce more intensity?

It is not a module problem, but a load problem.
For example, putting a short circuit at the output, you might get 2 or 10 A, but with 0V ...

The theory is simple: to obtain the maximum power the load must have an impedance equal to that of the generator ... which varies according to hot and cold temperatures.
The load must be constantly adapted to the operating point.
The equivalent of what MPPT do in the case of photovoltaics.

Thank you for your reply.

So if I understand correctly, it is the load (the fans for my case) which defines the intensity. The more the load needs power, the more it will demand intensity from my generator while influencing the voltage. The intensity will be limited by my modules which have a limit not to be exceeded.

If this is not what you wanted to explain to me, I apologize but my knowledge of electric vocabulary is poor.

Thanks again.

[Gaston]

So if I understand correctly, it is the load (the fans for my case) which defines the intensity. The more the load needs power, the more it will demand intensity from my generator while influencing the voltage. The intensity will be limited by my modules which have a limit not to be exceeded.

If this is not what you wanted to explain to me, I apologize but my knowledge of electric vocabulary is poor.

Basically, that's it, but it's a little more complicated.

The intensity is not "asked", it is established according to the characteristics of the generator and the load.
But the voltage also depends on the intensity supplied.

What makes that one is generally interested in finding the point of operation for which the load receives the maximum of electric power while playing on the only thing at our disposal: the resistance of the load.

If you want to test, I advise you to use resistors (bulbs, ...) rather as a load rather than motors whose impedance varies according to the speed of rotation (it becomes one more variable to calculate the point of equilibrium).

It turns out (it shows) that the load receives the maximum electrical power when its resistance is equal to that of the generator.
The internal resistance of one of the modules you use seems to vary between 2,8 and 3 ohms depending on the temperature.
For 8 modules in series, you will therefore obtain the maximum output power by placing a resistance of 22 to 24 ohms (i.e. a bulb of 6W / 12V approximately): you should then observe an intensity of 0,6A and a voltage of 14,5, 8V, or a power of about XNUMXW.

[johan07]

The intensity is not "asked", it is established according to the characteristics of the generator and the load.
But the voltage also depends on the intensity supplied.

What makes that one is generally interested in finding the point of operation for which the load receives the maximum of electric power while playing on the only thing at our disposal: the resistance of the load.

If you want to test, I advise you to use resistors (bulbs, ...) rather as a load rather than motors whose impedance varies according to the speed of rotation (it becomes one more variable to calculate the point of equilibrium).

It turns out (it shows) that the load receives the maximum electrical power when its resistance is equal to that of the generator.
The internal resistance of one of the modules you use seems to vary between 2,8 and 3 ohms depending on the temperature.
For 8 modules in series, you will therefore obtain the maximum output power by placing a resistance of 22 to 24 ohms (i.e. a bulb of 6W / 12V approximately): you should then observe an intensity of 0,6A and a voltage of 14,5, 8V, or a power of about XNUMXW.

Ok thank you, it's nice to have constructive answers.
I don't speak for everyone of course.

Tonight I'm going to give it a try with a led strip to see what it looks like.

So since my project will work , since my ambition is to recharge a battery, I would therefore be obliged to put a charge regulator.

Is it the regulator that will serve as my "load" and resistance or the battery?

[johan07]

Hello,

Suddenly yesterday there was a little problem.

My LED strip requires 1.25A and suddenly one of the modules to be grilled by connecting the LEDs to the generator.
Which is logical because Gaston told me 0.6A max for my modules.

Now if I choose other modules announcing a power higher than 12706, will it have a larger current capacity.

Let me explain, the 12706 modules are announced for 60W max. If I choose modules announcing at random 250 W max, logically the intensity will be higher for an identical voltage?

[izentrop]

Hello,
Following the previous pdf, however full of instruction that you did not consider constructive, it appears that:

Hi-z manufactures modules intended for the production of electricity which can produce 30 W with 230 ° on one side and 30 ° on the other:
http://www.hi-z.com/hz-20.html
On the load curve on the datasheet where we see that they are obtained at 4.5 V

[johan07]

Hello,
Following the previous pdf, however full of instruction that you did not consider constructive, it appears that:

Hi-z manufactures modules intended for the production of electricity which can produce 30 W with 230 ° on one side and 30 ° on the other:
http://www.hi-z.com/hz-20.html
On the load curve on the datasheet where we see that they are obtained at 4.5 V

Hi,

I allow myself to tu you because you allow yourself too.
When I spoke of a non-constructive message, I made it clear that I did not speak for everyone, of course. You should not feel targeted for this message because your pdf is very interesting. I read it entirely but I did not find the answers I was waiting for immediately. I downloaded it because it may be useful later.

[johan07]

The intensity is not "asked", it is established according to the characteristics of the generator and the load.
But the voltage also depends on the intensity supplied.

What makes that one is generally interested in finding the point of operation for which the load receives the maximum of electric power while playing on the only thing at our disposal: the resistance of the load.

If you want to test, I advise you to use resistors (bulbs, ...) rather as a load rather than motors whose impedance varies according to the speed of rotation (it becomes one more variable to calculate the point of equilibrium).

It turns out (it shows) that the load receives the maximum electrical power when its resistance is equal to that of the generator.
The internal resistance of one of the modules you use seems to vary between 2,8 and 3 ohms depending on the temperature.
For 8 modules in series, you will therefore obtain the maximum output power by placing a resistance of 22 to 24 ohms (i.e. a bulb of 6W / 12V approximately): you should then observe an intensity of 0,6A and a voltage of 14,5, 8V, or a power of about XNUMXW.

Ok thank you, it's nice to have constructive answers.
I don't speak for everyone of course.

Tonight I'm going to give it a try with a led strip to see what it looks like.

So since my project will work , since my ambition is to recharge a battery, I would therefore be obliged to put a charge regulator.

Is it the regulator that will serve as my "load" and resistance or the battery?

Small UP for the regulator question.

[izentrop]

Hi,
They are not always good advice, but there they explain what can be learned from this type of module.
https://youtu.be/gxu7mXjB5DU

A module designated as a thermoelectric generator, the SP1848-27145.
Its generator characteristics:
Temperature difference of 20 degrees: open circuit voltage 0.97V, power current: 225MA
Temperature difference of 40 degrees: open circuit voltage 1.8V, power current: 368MA
Temperature difference of 60 degrees: open circuit voltage 2.4V, power current: 469MA
Temperature difference of 80 degrees: open circuit voltage 3.6V, power current: 558MA
Temperature difference of 100 degrees: open circuit voltage 4.8V, power current: 669MA

About 3 W maximum, the 12706 should not provide more.

Read more: http://www.elecfreaks.com/store/thermoe ... z47FLlUOpP

[izentrop]

Hello,
Yep, again him!
A serious production attempt with modules capable of withstanding 300 ° http://www.customthermoelectric.com/pow ... ec_sht.pdf
The 12706 is 90 ° normal and 135 ° not to be exceeded.
200 W with 10 modules, but for this it is necessary to maintain a temperature of 300 ° on one side and 30 ° on the other. They don't say if they got them those 200 W
http://www.instructables.com/id/Thermoe ... eneration/
http://www.customthermoelectric.com/powergen.html