30A 14DC Way to Adjust Voltage or Amperage?

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The2x4

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I am installing a hydrogen fuel cell in my old car and need a way to control power usage. Power will be coming from the car through a 40A automotive relay, though I currently only need about 15A I want to be able to expand to 30A later (with bigger cell). Power adjustment would work with lowering current or lowering voltage (which would cause cell to draw less current), whichever would be more easily and inexpensively done.

I have found this which looks like it would work, but I can only find ones that ship from China, and was hoping for something cheaper and smaller.

Any help would be very appreciated.

Tom

BTW: I have a good multimeter and I can solder.
 
The problem is that the HFC draws more current as it warms up, which eventually leads to overheating. If I were to get the perfect electrolyte mixture, I could possibly prevent this, but if the mixture changes at all after use it could ruin it. I will have an ammeter to see if it is pulling enough to overheat, at which point I will need to adjust it slightly. I am looking for a way to adjust it, so I can use nearly any electrolyte mixture.

Thank you for trying to help though.
 
The2x4 said:
I am installing a hydrogen fuel cell in my old car ...
Click to expand...

I thought the goal of a fuel cell is to produce energy, not to have to pour energy into it. This thing is not a fuel cell; it is simply electrolysing water into H2 and O. Why not just buy a tank of Hydrogen, and then you will soon figure out that it is way more expensive than the gasoline you are trying to save...
 
Not having that debate here

I disagree with you, but this is not a thread about Hydrogen efficiency. I need an electrical circuit, not advise on hydrogen.
 
The2x4 said:
I disagree with you, but this is not a thread about Hydrogen efficiency. I need an electrical circuit, not advise on hydrogen.
Click to expand...

Disagreeing is irrelevent. You're converting energy stored in the gasoline to energy stored in hydrogen and since no conversion process is 100% efficient, the hydrogen ends up with less energy stored in it than the energy you used to produce it. SO when you use it, you'll get less energy from it than the gas that you used to make it.

But none of that matters because the fact that you called it a fuel cell doesn't match up with what you describe it as doing. Fuel cells take hydrogen and make electricity. Electrolyzers take energy (From somewhere) and make hydrogen. It's the wrong machine! It's like saying you're installing an alternator when you're actually installing an air conditioner.
 
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Like I said, I do not want advise on hydrogen, gasoline, or any other energy besides DC Electricity.

I would like to know an easy way to make the voltage or current adjustable.
Approx 5A-30A and 6V-14V DC.

Please refrain from any posts about whether or not hydrogen fuels cells make any sense or not.
 
I am trying HHO as a learning experience, and to see if it works or not. Many brilliant people have said it works, some have not. I am going to find out for myself. I have put together a decent cell for $30 and figure I should learn enough in the process to make it worth it. Therefor I am not wasting anything, and my car is over 30 years old so it may just help the gasoline burn completely. Please do not try to say it is a stupid idea, I am finding out for myself and learning other things in the process.

Please just tell me how to make the control unit for it!
 
You may either need to do a PWM system or a second alternator that has had the regulator system redesigned to change the output to a variable system.

I have ran a few engines on hydrogen and oxygen (from tanks) and without engine modifications its a considerable step backward in efficiency and power output.
Hydrogen and oxygen at its sticheometric ratio needs nearly double the compression that a normal gasoline fueled engine works at. Without that high compression much of the power it can produce never gets turned into mechanical power.
 
I do have a PWM system for my cell, but it is only designed for 10A MAX, and doesn't work as well with my flat plate design.

I am just looking for a way to have an adjustable limit on the current or an adjustable reduction to the voltage.

I actually have an old 6V Generator, and a place where it could be installed in my car, but I would still need a way to up the voltage, then fine-tune adjust it, so my cell works well, but doesn't overheat (my HHO cell doesn't work well on less than 10V).

Thanks for the relevant post and suggestions tcmtech.
 
Using a second automotive alternator with a hacked Voltage Regulator is probably the way to go. Normal VRs already PWM the alternator field, with the max field current being only about 2A.

By hacking the set point voltage circuit inside the VR, the alternator will be able to produce a continuously adjustable voltage from ~2V all the way to ~50V. The max available current will be limited by core saturation to about 50A. Note that an alternator producing 50A at 15V is sucking ~ 750W or about 1HP from the engine.
 
Okay, I have a Farmall 140 Generator 6V 1100042. Could I do that to the generator, and if so, how would I adjust it? I have basic knowledge and limited experience so a step-by-step would be nice (not baby steps, but not expert steps either).

Thank you for the help.

Tom
 
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A generator is not the way to go. With an alternator, you PWM the field current (~2A) to get 50A. With a generator, you have to PWM the full 50A.
 
I have replaced dozens of the old farmall generators with alternators and as far as I can recall those old 6 volt generators rarely could put out more than 15 amps. Most had a hard time putting out 10 amps into a near dead battery. Your cigarette lighter is capable of more wattage than what one of those old 6 volt generators is capable of.

For easy to hack alternators the older Ford and Chrysler units had external regulators so they are easy to control with a different regulation circuit. The GM alternators are better built and more efficient but they have internal regulators so the alternator has to be taken apart in order to bypass the internal regulator system. Its not hard to do though.
 
The alternator idea does sound good, but a little expensive for my current budget. I am looking for something incredibly cheap (I only spent about $30 on the cell itself).

I am not sure, but it seems the POTs on a (somewhat older) stove just let through x Amps on 'LOW', y Amps on "MED", and z Amps on "HIGH". Is this correct? If it is the case, I should be able to use one, or even a couple in parallel, to limit the Amps going to the cell. As I already have a few POTs in a scrap stove, this would be about the cheapest option.

Would that work?

Thank you again for the advise.

Tom
 
An older (I assume mains operated) stove has several heaters in each coil. The "pot" actually attached different elements according to how much heat you wanted.
 
Ok, stove POTS do not work for this.

What if I were to modify my PWM circuit to handle more than 10A? I did not build it, but it looks to me like the only limiter on it is the last transistor (NTE2376). If I were to switch out that for 1 or 2 2n3055 (15A) transistors that I have, would that work? If so, how would I wire them up (they only have 2 legs)?
 
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Some pics of current PWM:

**broken link removed**
**broken link removed**

Black and (Big)Green wires go to transistor with heat-sink.
 
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