The International Open Source Hydrogen On Demand Builders Network.
For efficient electrolysis the voltage across the electrodes and the number of ions - charges carries - are crucial. It was stated in several academic studies that manipulation of voltage increase the electrolysis efficiency.
When I start working in this field I read as much I could and I trust others who seems to succeed.
In time realize that even professional system in the industry do not apply correctly the potential of power supply manipulation and electrodes geometry in order to achieve best efficiency but I guess is about the separation of gases in as much less expensive systems.
For common duct electrolysis the most so call experts in so called HHO generation are wrong or present misleading information's.
Using a PWM, a switch on cathode to negative pole - a constant current lately - is not the way to make efficient electrolysis as I was told!
The input voltage is relative fixed, let say 13.5-13.8 V. The current is usually good enough from any automotive battery.
Making a common duct electrolyser with 7 cells in series is most usual design. The voltage is divided to less than 2 volts per cell and if due electrolyte concentration the conductivity is fair. Due heating effect the system reach a certain maximum current running good, and not overheat.
But this is time consuming method. Such constructions reach operational parameters after long time.
It also need a certain constant concentration of electrolyte.
So, most of the manufacturers use only 6 cells and a PWM placed on cathode. This switch on and off very fast ( various frequencies are proposed as the best - in fact this depend on system's electrical parameters).
A CCPWM keep a certain preset-able current value and some are pretty good!
But this not make more gas, nor improve the electrical efficiency.
It prevent the lost of efficiency by limiting the total power used but per peak of current the values are still the same. Certain cells not works better not even with most sophisticated CCPWM.
I have tested various methods, using all kind of otherwise unusual electric connections, coils, capacitors etc. Most not works ...
As anyone can see on my page I reach a resonant point where despite the system produce a useful work equivalent for a certain way larger power ( in normal operating conditions) .
But this is another subject.
What I found useful is a power supply that is common in electronic world: a DC/DC booster.
Using a DC/DC booster the number of neutral electrodes can be increased based on the behavior of electrolyte as resistor. At beginning with 14 V and 8 cells in series the voltage per cell is too low to even make bubbles. Here is where the DC/DC booster works first. It rise the voltage to reach a certain current ( either one preset either its maximum by design - NOTE that is not only the electrolysis current counted for its maximum). Once the electrolyte get warm the conductivity increase and the voltage per cell may drop. This is what the DC/DC booster will do.
Overall it may reach a desired temperature and current with REAL lower voltage per cell and more cells in series at same voltage. THIS is efficiency!
Voltage is used properly, current and current density per electrodes surface are used properly. Larger surface exposed mean even one or two more "neutral" electrodes for same voltage.
Overall the power usage for gas volumes is better.
Attached is a mini-model suitable for maximum 10 A for electrolysis at 14 volts battery.
Good enough to produce one liter of gas per minute on a good cell or even more.
It can be found on Ebay or Alibaba probably.
I can offer one unit that I tested, at demand. Is in any case better deal in technical and money terms than any PWM's one can buy!
Later I will present an automotive grade improved model that may work above 300 W and can increase the gas production at acceleration - using the heat produced to reduce the consumption a while on deceleration and cruise.
More other additional device will come ( like electrodes design to improve the gas volumes, adds-on equipment to improve the gas effect on engine etc)
Not seen it on TV! ( :-) ) and I think that nor on other "manufacturers" offer ( yet).