Anyone want to lower their cell temperature?

[Philldpapill]

I've got a good way... This really only applies to those cells that use a PWM to regulate the current through them. In addition, it applies to those cells that utilize a fairly low duty cycle(<90%)...

The idea, is that when you are using a PWM, the instantaneous current through the cell is simply a function of the input voltage, divided by the cell resistance - a.k.a. Ohm's law = I = V/R. Nothing special here.

However, POWER loss(heat) is a function of the integral of the current squared. If you are feeding your cell a square wave from a PWM at 50% duty cycle, then the AVERAGE current would be, say 30A, while the maximum current for nearly 50% of the time, would be about 60A peak. When comparing the power loss of a 50% duty cycle, 60A peak square wave, to a 30A smooth current, the power loss is:

(R being the resistance of your cell)
60A peak, 50% duty = 60^2*R*(50%) = 1800*R
30A peak, 100% duty = 30^2*R*(100%) = 900*R

In other words, if you are using a 50% square wave, your power loss is roughly TWICE as much as if you were using half the current, but a smooth signal.

Since the amount of HHO is a function of how much charge passes through the cell(current * time), we can safely say that the two schemes listed above should produce about the same amount of HHO. Since we are making the same amount of HHO, and the power is reduced using the second method, we can also say that our MMW will be better as well!

So, how do we smooth the current??? Pretty easily, it turns out. Using an power inductor and a single high current diode, we can manage to smooth the current to a pretty fair degree. However, there will be SOME additional power loss in the inductor and diode, but this should be minimal when compared to the gain by using this method.

To understand what needs to be done, you may want to research what an inductor and/or a diode is. A diode essentially allows current to pass one way through it. An inductor resists changes in current, so if current is flowing through it, by god, that current will keep flowing through it(for a while...). Using the inductor, we can set up a fairly constant current, by means of a PWM. To do this, the PWM frequency will need to be set fairly high(frequency depending on the value of inductance used).

The circuit is attached. More to come later, but I've got a date. :D

<a href="http://s91.photobucket.com/albums/k297/Philldapill/?action=view&current=SimpleBuck.gif" target="_blank"><img src="http://i91.photobucket.com/albums/k297/Philldapill/SimpleBuck.gif" border="0" alt="Buck"></a>

[Helz_McFugly]

Ive seen Zero's PWM waves on his o-so-silly-scope and they are perfectly square. so if you monitor your PWM with the inductor & diode on a scope would they not be square? what would it look like?
most of what you said is so far over my head its a spec in the sky. but I get the idea.

[richard_lyew]

I've got a good way... This really only applies to those cells that use a PWM to regulate the current through them. In addition, it applies to those cells that utilize a fairly low duty cycle(<90%)...

The idea, is that when you are using a PWM, the instantaneous current through the cell is simply a function of the input voltage, divided by the cell resistance - a.k.a. Ohm's law = I = V/R. Nothing special here.

However, POWER loss(heat) is a function of the integral of the current squared. If you are feeding your cell a square wave from a PWM at 50% duty cycle, then the AVERAGE current would be, say 30A, while the maximum current for nearly 50% of the time, would be about 60A peak. When comparing the power loss of a 50% duty cycle, 60A peak square wave, to a 30A smooth current, the power loss is:

(R being the resistance of your cell)
60A peak, 50% duty = 60^2*R*(50%) = 1800*R
30A peak, 100% duty = 30^2*R*(100%) = 900*R

In other words, if you are using a 50% square wave, your power loss is roughly TWICE as much as if you were using half the current, but a smooth signal.

Since the amount of HHO is a function of how much charge passes through the cell(current * time), we can safely say that the two schemes listed above should produce about the same amount of HHO. Since we are making the same amount of HHO, and the power is reduced using the second method, we can also say that our MMW will be better as well!

So, how do we smooth the current??? Pretty easily, it turns out. Using an power inductor and a single high current diode, we can manage to smooth the current to a pretty fair degree. However, there will be SOME additional power loss in the inductor and diode, but this should be minimal when compared to the gain by using this method.

To understand what needs to be done, you may want to research what an inductor and/or a diode is. A diode essentially allows current to pass one way through it. An inductor resists changes in current, so if current is flowing through it, by god, that current will keep flowing through it(for a while...). Using the inductor, we can set up a fairly constant current, by means of a PWM. To do this, the PWM frequency will need to be set fairly high(frequency depending on the value of inductance used).

The circuit is attached. More to come later, but I've got a date. :D

<a href="http://s91.photobucket.com/albums/k297/Philldapill/?action=view&current=SimpleBuck.gif" target="_blank"><img src="http://i91.photobucket.com/albums/k297/Philldapill/SimpleBuck.gif" border="0" alt="Buck"></a>

this is kinda backing my post that i made earlier when i said "the direction we will end up is high voltage and high frequency"

good post phill

[Philldpapill]

No, this has nothing to do with that post, Richard. Don't taint this thread with all that nonsense again...

THIS has to do with providing a smooth, LOW voltage, current to the cell. The frequency is ONLY to sustain a stable current and NOTHING to do with the actual electrolysis.

The point of this add-on, is so that the electrolyte ONLY sees the stable current. In fact, this sort of circuit is a type of LOW-pass filter, meaning only the low frequencies get through. The circuit results in less wasted heat from ohmic heating.

You can contribute, but please, Richard, don't inject any magical "not-understood" garbage. The idea behind this is a basic power system concept in E.E.

[Helz_McFugly]

Phill. are you building me a PWM? Im getting one with a "lot" of HHO suff Im buying but I really want the one you described to me earlier. just let me know what I owe ya or if you want some $ up front being that you live under the IH45 bridge and need the $. :p

[will build PWM for food]

[hg2]

Phill. are you building me a PWM? Im getting one with a "lot" of HHO suff Im buying but I really want the one you described to me earlier. just let me know what I owe ya or if you want some $ up front being that you live under the IH45 bridge and need the $. :p

[will build PWM for food]


I gotta throw my 2 coppers in here because I think you guys are off base regarding a PWM's true function with an HHO system.

Back in Jan. of 09 I refitted my large dry cell with 1/16" spacer gaskets from 1/8" and the amps went wild(as did my output).My heat wasn't out of control but after the cell warmed the amps like most cells rose to over 70 .After discussing this with one of the members here he suggested that I talk to Shane Jackson about him building me a custom high amp PWM with 2 built in mosfets,tested to over 100 amps.

What the PWM did was keep my amps at an adjustable constant so my start up amps were the same as my warmed up amps thus giving me full control and being able to run the system at it's peak output even using a strong maximum e-lyte of 28% by weight KOH to distilled.I adjusted the amps so they were a constant 57 to 60 amps,which seemed to be the peak of performance for my cell and my charging system.

So as they say here on the HHO forum sorry to disagree but...........

[Philldpapill]

hg2, I must be a little stupid tonight... I don't understand where you disagree.

The PWM design I'm talking about provides a CONTINUOUSLY smooth output current. The PWM shane jackson made(originally from zero fossil fuel) incorporates some feedback so that the current over a PERIOD remains constant. However, with his design, you will still have the current peaks, which result in unwanted power dissipation.

With a true continuous current PWM, the average current and RMS current are the same. In other words, there are no high peak currents in the cell. This PWM design will also incorporate current feedback, so that it too is constantly adjusting the on/off times of the PWM.

What do you disagree with?

[Helz_McFugly]

when you would start it off cold at 57 to 60 amps what was your HHO output?
and after it warmed up still drawing 57 to 60 amps what was the HHO output?
How long did it take to warm up and how warm did it get at its peak with that KOH mixture?

[Philldpapill]

@Helz,
I've sourced some parts for the PWM units I'm building. I can't remember which type you wanted... 120VAC or 12VDC input? I've got way too many projects of similiar nature going on...

As for the AC version, I think I've sourced some critical parts I needed. I'll try to get a prototype going next week. The cost is looking to be about $80 now... Things just keep adding up. What current rating did you want(assuming the 120VAC, up to 100VDC output)? I think you had said something about up to 75A... Remember, you can always use the higher output voltage to add more cells in series, then put the cells in parallel for a 12VDC use. Also, if you REALLY want 75A, at the 100VDC output voltage, that's 7.5kW of power, man! Yikes.

Anyway, let me know what you want in this thing... I, too, have a shltty memory.

@Richard,
Please stop quoting long-a.ss posts by others. In this case, there was ONE other post before yours(Helz's). It's pretty clear who you were talking about, but by quoting everything anyone says, it makes the forum cluttered.

[Helz_McFugly]

HA, no im not wanting a 100VDC/75 amps AC to DC. maybe a good ac to dc LATER, I have a good power supply for bench testing for now.. but yea one for a car. Digital LCD screen with Ampmeter and a volt meter on it. It would be nice to be ably to mod it with my laptop but thats not a demand. something that runs at peak 13.8VDC/150amps but Im sure I wont need more then 100 amps. I thought I had a 150 amp alternator on my car, because my brother said thats what he gave me, but I was told they dont make one for my car unless it was a custom build which it could have very well have been. Its probably a 160amp. I dont know untill I talk to his flakey a$$ tomorrow.

Im pretty sure I wont be needing a PWM for 13.8VDC/100 amps in any of my cars. the largest enging I have is a 3.5 liter. V6.

[Philldpapill]

Whooooa..... 150A? Good god. That's a lot of current. I'm not sure what kind of dummy load I can use to test something that big! Hmmmm, HHO Cell perhaps? Damn, I don't have one that big. Mine only takes about 30-40A. I'll rig up something to test.

[hg2]

Phill

I never saw the feed back you mentioned only a steady amp draw no matter what stage of start up or warmed up the cell was in.That was the goal I was looking for that was total control of the high amp draw and also to keep the cell per plate voltage at 2.15 to 2.25 vdc..Even without the PWM the cell never had a heat issue(the beauty of dry cells)I don't really see where you see issues with feed back and BTW just how much do the think it affects production?

I guess what some people think that that waves square or not will dramatically affect the average cells that those of us install on our vehicles and IMO they(PWM's) play no role except to efficiently control amperage only.Sure when you get into high tech high voltage systems that rely on frequency like the ones utilizing Toroidial coils such as the ones in Boyce's experiments,that are so radical you can have the FCC breathing down your neck for interference.
Phill I guess what I'm trying to say is that just a regular constant current PWM is all that's needed to efficiently run a system large or small for installation on a vehicle.




Helz to answer your questions they're some variables that affect the answers so I'll do my best.
On initial start up the cell would put out as little as 2 1/2 LPM when the ambient air temp was low and up to almost 4LPM when the temp was higher.On average the cell would peak at around 4 to 41/2 LPM(although I have had it up over 5 LPM).The cell temp never really got over 115* F to 120*F(and probably 15* to 20* more without the PWM).Your question regarding how long the cell took to warm to peak was also affected by ambient air temp and would vary some but not greatly.And down here in Fla. the weather is like a box of chocolates you never know what the fawk you're going to get from day to day.

[hg2]

Whooooa..... 150A? Good god. That's a lot of current. I'm not sure what kind of dummy load I can use to test something that big! Hmmmm, HHO Cell perhaps? Damn, I don't have one that big. Mine only takes about 30-40A. I'll rig up something to test.

That's funny you mention that Phill,
Shane Jackson said he ruined a good screwdriver testing mine and the 2 built in mosfets held fast with no problem.Shane said that was at around 130 amps if I remember right.

[IM2L844]

when you would start it off cold at 57 to 60 amps what was your HHO output?
and after it warmed up still drawing 57 to 60 amps what was the HHO output?
How long did it take to warm up and how warm did it get at its peak with that KOH mixture?I'm glad you brought this up, Helz. Only the apparent volume would change. The warmed up output may contain a little more water vapor, but the energy containing amount of HHO would stay exactly the same. By way of Charles's Law plus the added water vapor it would just take up more space. The energy content wouldn't change one bit.

The increase in water vapor with temperature is exponentially proportional. Beginning at about 100* F you can expect the water vapor content to increase a full percentage point with every 2 degrees F increase in temperature. For example at 100* F you can attribute about 3% of the volume to water vapor and at 120* F you can attribute about 13% of the volume to water vapor. When you start getting close to 200* F, the rate of increase starts to approach infinity and trying to determine water vapor content starts to become a superfluous endeavor.

[Helz_McFugly]

so all the jargin I see when these guys are selling their electrolyzers and they say "its at 5 amps and only puting out about X amount of HHO right now because its only been running for 2 minutes BUT it will put out Z ammount when its nice and warm and still be at 5 amps". Isnt correct. I doubt they are try to be misleading. Im sure they just dont know.
So Its just the expansion of the gas as it warms & water vapor displacement making it measure more output?

Good to know.

[IM2L844]

so all the jargin I see when these guys are selling their electrolyzers and they say "its at 5 amps and only puting out about X amount of HHO right now because its only been running for 2 minutes BUT it will put out Z ammount when its nice and warm and still be at 5 amps". Isnt correct. I doubt they are try to be misleading. Im sure they just dont know.
So Its just the expansion of the gas as it warms & water vapor displacement making it measure more output?

Good to know.Exactly. Remember, also, water vapor takes up just as much space, proportional to it's content percentage, as does HHO.

Something else to keep in mind when considering water vapor content is that researchers at Brookhaven National Labs have determined that the temperatures inside an electrolyzer, where the gases evolve, from the innermost cell to the outermost cells, consistently run 12 degrees F hotter than the temperature readings taken with an IR thermometer anywhere on the outside of the electrolyzer.

[richard_lyew]

No, this has nothing to do with that post, Richard. Don't taint this thread with all that nonsense again...

THIS has to do with providing a smooth, LOW voltage, current to the cell. The frequency is ONLY to sustain a stable current and NOTHING to do with the actual electrolysis.

The point of this add-on, is so that the electrolyte ONLY sees the stable current. In fact, this sort of circuit is a type of LOW-pass filter, meaning only the low frequencies get through. The circuit results in less wasted heat from ohmic heating.

You can contribute, but please, Richard, don't inject any magical "not-understood" garbage. The idea behind this is a basic power system concept in E.E.

yea yea yea but you i meant the same thing, very very good thread thou.

Thanks

[richard_lyew]

Phill. are you building me a PWM? Im getting one with a "lot" of HHO suff Im buying but I really want the one you described to me earlier. just let me know what I owe ya or if you want some $ up front being that you live under the IH45 bridge and need the $. :p

[will build PWM for food]

one the most important thing you could buy is a AFC, you dont have to buy the NEO now, just buy a SAFC or a VAFC if you dont have enough $ right now.

[Philldpapill]

hg2, we are saying the same thing... I don't think a PWM does anything magical(even at high frequencies). All it does, is quickly turn the power on and off to the HHO cell, thereby modulating how much average current is pushed through. However, as I displayed above, the amount of HEAT that is wasted is in fact a function of the peak currents. An average PWM unit only outputs hard square waves with larger than needed peak currents. What I am proposing would smooth these peaks out to lower average values. With lower peak currents, less power will be waste by producing heat.

In effect, if your cell is getting too hot, you can use this setup to lower your power dissipation. If your cell is running just fine(not too much heat), you can use this setup to increase the maximum average current, without excessive heat production. With a normal PWM, you can't do either of those.

Remember, this setup is an "add-on" for existing PWM's. It consists of only two components, yet has the potential to decrease heat without sacrificing HHO production. Call it an "MMW booster".

The parts can be had from most electronic shops. I've found a source for high-power inductors, but you may need to wind them yourself. If not, I can do it for anyone who wants to try - at cost of course. I'm just curious how this setup would react with other people's PWM's.

[Philldpapill]

What is an AFC(and all those acronyms you listed), Richard?

[richard_lyew]

I gotta throw my 2 coppers in here because I think you guys are off base regarding a PWM's true function with an HHO system.

Back in Jan. of 09 I refitted my large dry cell with 1/16" spacer gaskets from 1/8" and the amps went wild(as did my output).My heat wasn't out of control but after the cell warmed the amps like most cells rose to over 70 .After discussing this with one of the members here he suggested that I talk to Shane Jackson about him building me a custom high amp PWM with 2 built in mosfets,tested to over 100 amps.

What the PWM did was keep my amps at an adjustable constant so my start up amps were the same as my warmed up amps thus giving me full control and being able to run the system at it's peak output even using a strong maximum e-lyte of 28% by weight KOH to distilled.I adjusted the amps so they were a constant 57 to 60 amps,which seemed to be the peak of performance for my cell and my charging system.

So as they say here on the HHO forum sorry to disagree but...........

hi, whats the rating on your alternator?

[Philldpapill]

@hg2,
Any idea what MOSFET shane was using for that two-transistor PWM??? If they are in a TO-220 package, then shane isn't being honest. The leads on the transistors can't sustain 75A. After about 30 seconds, the leads on that type of industry-standard package will MELT.

He may have pulsed the unit with 150A, but I seriously doubt it can sustain it for even a minute. Just because the silicon in the mosfet can handle 75A, does NOT mean the packaging can.

[hg2]

Ok Phill I see which way you're going with this now,I guess I missed the add-on part somewhere.Interesting concept though I'd like to see some future data on it when you have some available.

[Helz_McFugly]

@Phill Im not planning on having a system that uses even close to 2000 watts. just saying. thats what this alternator can push 13.8VDC/150 amps. Ide like to keep my system under 75 amps but want to be able to access 100amps if need be. say, if I make my cell bigger or want to run 2 or 3 in parallel.

here is the top of the line AFC http://tiny.cc/M9ljr
it lets you control your A/F ratio. Ive been told by some HP guru's it doesnt work well with OBD2.
but its way off topic for this thread. Its just a glorified EFIE

@HG2
How many amps did the elctrolizer I PM'd you about pull with the 7 plate config? and Im assuming it was setup like +nnnnn-. also how many amps with 8 plates?

[hg2]

Helz

I never went back to 8 plates after refitting the cell with 1/16" gaskets last winter because I got the output I was looking for after the refit.I can tell you that with the 1/8" thick gaskets I was drawing about 40 to 44 amps with 7 plates and about 12 to 14 amps with 8 plates.And yes you're correct the configuration is -nnnnn+ with 7 plates.
This was also without using a PWM,I bought that after the refit because with the 1/16" thick gaskets and using 28% KOH by weight(that's about 2 lbs.to 1 gallon of distilled water)the amp draw completely buried my 60 amp gauge and I could only estimate it was drawing between 70 and 80 amps.Hence the reason for buying the PWM from Shane Jackson.The amp draw was so great without the PWM with everything off(a/c,lights ect) and the truck idling the volt meter on the truck would plummet to the point the ECU would shut down the charging system,a little feature the OBD II has to prevent you from shooting yourself in the foot drawing too many amps.

BTW I left you and email around 6:30 pm your time,did you get it????

[Buster]

one the most important thing you could buy is a AFC, you dont have to buy the NEO now, just buy a SAFC or a VAFC if you dont have enough $ right now.

Do you have some links for the SAFC & VAFC and any particular recommendations?

[Helz_McFugly]

here is the top of the line one http://tiny.cc/M9ljr
you can google them and find alot

[IM2L844]

I'm not much of an electronics kind of guy, but I've often wondered if a variable voltage regulator could be used insted of a PWM and just allow the inherent resistance to regulate the maximum current...or is this limited understanding way off base? I don't have a clue about how the inner workings of a variable voltage regulator might operate.

[Philldpapill]

@IM2L844,
Most high-power "variable voltage" supplies utilize a switching power supply. This involves stepping up/down the voltage using an inductor, then using a linear regulator to provide a very smooth output.

I believe what you are talking about is a linear regulator. Those are VERY inefficient. However, for very light loads - like in a simple discrete component circuit, they are just fine. For a high-power design, they waste nearly as much power as they deliver to the load.

A PWM is used to regulate the AVERAGE current, but does little to regulate voltage/current peaks across the load. It's like switching a light switch on and off really fast to adjust the brightness of a lamp. It "works", but the lamp still sees harsh peak currents.

[Helz_McFugly]

@Phill, Im a gun nut so when ever youre done with that PWM and read to get it to me, We can meet at The gun range Im a member of, if you like to shoot that is, and Ill bring some really cool **** you can make go BOOM! Hell I can even get some targets made of choice people if ya like. http://www.mysmiley.net/imgs/smile/fighting/fighting0002.gif
what I like to do is spray sugar water on the targets and shoot the flys off at 50 yards. http://www.mysmiley.net/imgs/smile/fighting/fighting0007.gif

[IM2L844]

@IM2L844,
Most high-power "variable voltage" supplies utilize a switching power supply. This involves stepping up/down the voltage using an inductor, then using a linear regulator to provide a very smooth output.

I believe what you are talking about is a linear regulator. Those are VERY inefficient. However, for very light loads - like in a simple discrete component circuit, they are just fine. For a high-power design, they waste nearly as much power as they deliver to the load.

A PWM is used to regulate the AVERAGE current, but does little to regulate voltage/current peaks across the load. It's like switching a light switch on and off really fast to adjust the brightness of a lamp. It "works", but the lamp still sees harsh peak currents.This begs another question. When trying to determine efficiency, what is the proper way to take voltage and amperage measurements when using circuitry that obviously has some degree of work being performed (power or energy being consumed or dissipated) within it?

[biggy boy]

LR filter, good topic Phil!

what cut off freq are you aiming for? fc = 18724110952 Hz?

[Philldpapill]

@IM2L844,
The way you measure the "efficiency" of a regulator like I'm talking about, would be pretty simple. Measure the voltage/current across and through the load and find the Power, P_load. Then, measure the voltage/current across/through the regulator and call that power P_reg.

Efficiency = (P_load/P_reg) * 100%

@biggy boy, Yep - kinda. It's more like a buck converter, but similiar. A buck converter takes a higher voltage, and steps it down to a lower voltage using an inductor, diode, and a switching mechanism. It essentially "charges" up an inductor(gets current flowing through it), then disconnects the inductor from the source. This produces a voltage of opposite polarity across the inductor, which keeps the current flowing until it dies out. In this case, the switch comes back ON before the current dies down TOO much, allowing a fairly constant current to flow.

The high power PWM I'm desiging is having some major issues though. Doing some simulations, I'm going to be loosing around 40-50W right off the bat, at 50-60A. If I could find a super low ESR Capacitor, I think I could lower this to 20-30W... Still, not TOO bad for a 600W PWM, I guess.

[IM2L844]

What I meant was: I've read a few white papers that said it is very difficult to get accurate voltage readings from the output side of a PWM. I suppose this has to do with the voltage spikes you were talking about. This makes me wonder if the current readings from a PWM output are also inaccurate.

If simply using a meter connected between a PWM and an electrolyzer to measure the output voltage of a PWM is not accurate, what would be the best way to measure the actual voltage and current reaching the electrolyzer.

[Roland Jacques]

I measure the total system voltage and amperage before the PMW. That's always been the bottom line figure of concern for me.

I wonder if the spike help or hinder in the forming of HHO in the electrolyzer. It might be hard to tell.

[IM2L844]

You may be right, but in the papers I've seen the engineers went to a lot of trouble creating methods and devices to measure the output side. Who knows? Those wacky engineers are always making things more difficult than they need to be. Hell, they even hold contests to see who can make the simplest of tasks the most complicated. Eh, Phill? jk

[Helz_McFugly]

My wife would have made a great E.E.

[biggy boy]

Phil can you give use the details for making the inductor IE:
type wire: magnetic or other, gauge, number of turns, core type: air, ring, rod....., Diameter.....

Ive got a spool of 18 gauge magnetic wire, I guess it's to small:confused:
I'm a self taught electronics hobbies, so don't know all aspects of electronics, I only learn what I need for a particular project at a time:o

Most of my projects to date have used RC filters for Dc power supplies (ripple) and for audio filtering low and high.

Thanks

[biggy boy]

I wonder if the spike help or hinder in the forming of HHO in the electrolyzer. It might be hard to tell.

I was wondering the same thing.
I thought I read somewhere that the current spikes are beneficial for HHO production.:confused:

Phil is that how an electronic battery charger works? It pulses the battery, in an attempt to desulfate the plates. Kind of blasts the sulfate coating off over time.

[IM2L844]

I wonder if the spike help or hinder in the forming of HHO in the electrolyzer.I don't want to get all sci-ency on ya, but I have speculated on the possibility that using a PWM somehow retards the formation of an interfacial double layer and that may affect efficiency for the better. I just don't know enough about it to form a complete hypothesis. I am only a lowly geologist who has been independently studying electrochemistry for a couple of years. Phil may be able to shed some light on this. <shrug>

[Philldpapill]

@IM2L844 - #34
Sorry for the dumbed down response above... I thought you were asking how the efficiency was calculated(which sounded like an overly simple question from you to begin with). Yes, the pulsating nature of the PWM does in fact give erroneous readings. I've often wondered if many of these extraordinary claims about MMW are in fact people just getting bad readings. The reason why many meters don't measure PWM signals very well is because the signal is made up of square waves. What happens, is the meter takes discrete samples every so often, and is averaging these samples over time to give you a reading. This is for digital meters ONLY - not the analog meters.

In an extreme case, let's say that your meter is sampling at exactly the same frequency as your PWM. Just by coincidence, it's ALSO sampling when the PWM goes low(off) each cycle. The meter would say there is no current flowing, which is obviously wrong. In the more realistic scenario, the sampling frequency and PWM frequency are probably different, but the meter STILL isn't sampling all the ON and OFF times proportionally. If you are trying to measure DC current, this is a very bad way of measuring because most DC meters take the AVERAGE current, and not the RMS current. Big difference.

The same applies to voltage, and current. Inside the meter, both are measured in a similiar way, while the current just passes through a shunt(low resistance resistor), then a voltage reading taken from that.

What you really need for accurate measurements, is a "True RMS" meters. They are a bit more pricey than your average $25 multimeter, but they have a much higher sampling frequency and calculate RMS readings or average readings.

@Roland - #35
Measuring the current before or after the PWM should give you pretty much the same results. The PWM circuitry shouldn't take anywhere near a single amp, and if it does, trash it - it's broken. Measuring the voltage before or after, DOES make a difference. Even when the PWM is fully on, the MOSFETs inside it will still drop a litte bit of voltage - maybe 500mV tops? So, yes, measuring the voltage before AND after to get an efficiency measurement is a must. Actually, just taking the ratio of output/input voltage would give you efficiency since input/output current is the same(virtually).

@IM2L844 - #36
Yeah, we do complicate things sometimes... Some people more than others, but most of the time, people fail to realize that things are designed around ALL worst case scenarios. However, sometimes it IS just for the hell of it. I remember back in my first year of college, my "introduction to engineering" course had a group assignment to make a moustrap "Rube Goldberg Machine". We had to make a mousetrap(toy mouse) that had X number of arbitrary steps in it to catch the mouse. The goal was to make it as complicated as possible...

@biggy_boy #37
I have some ferrite toroids I've been winding, but I need more. Here is one I'm thinking about buying in bulk: http://www.surplussales.com/Inductors/FerToro/FerToro-3.html

(ICH) FT44916-ZW - It's the second one down in the left column. It has very high permeability, meaning it shouldn't require as many turns to get the same inductance value. My toroids are similiar, but a smaller permeability value and I have 7.5mH from 53 turns of AWG#10 magnet wire. #10 is actually bigger than needed, because the toroid core will probably saturate at around 20-25A, so #12 should be fine.

For that core I specified, I think you should be able to get by with about 35-40 turns, and still get around the same inductance value. If your PWM is using more than 25A, just add a second, third, or fourth inductor in parallel(25A per inductor). The inductance value is already very high, so putting more inductors in parallel is ok(maximum ~7).

@biggy_boy/IM2L844,
I really couldn't tell you. Electronic battery chargers generally are switching supplies that monitor the voltage on the battery, and charge accordingly... As for high frequency pulsing for desulfation, yes, I don't remember what goes on, but I know it breaks up any sulfates on the plates - not my area. Chemistry, to me, is voodoo magic. :D

[IM2L844]

Now were getting our money's worth out of this guy. LOL. Thanks, Phil.

[biggy boy]

@biggy_boy #37
I have some ferrite toroids I've been winding, but I need more. Here is one I'm thinking about buying in bulk: http://www.surplussales.com/Inductors/FerToro/FerToro-3.html

(ICH) FT44916-ZW - It's the second one down in the left column. It has very high permeability, meaning it shouldn't require as many turns to get the same inductance value. My toroids are similiar, but a smaller permeability value and I have 7.5mH from 53 turns of AWG#10 magnet wire. #10 is actually bigger than needed, because the toroid core will probably saturate at around 20-25A, so #12 should be fine.

For that core I specified, I think you should be able to get by with about 35-40 turns, and still get around the same inductance value. If your PWM is using more than 25A, just add a second, third, or fourth inductor in parallel(25A per inductor). The inductance value is already very high, so putting more inductors in parallel is ok(maximum ~7).


OK thanks!
I would want two of them then.
Only problem I will have is where I buy my components. They sell their wire by the spool only, not by the foot. The cost would be to much for this size of a projects. I'll see if they have anything pre-made.

What would be the min and max range for the uH value, in case they don't have one close to 17uH?

Or could I use the #18 I have and just make more inductors to handle a 30-40amp load? Of course the number of turns would be different. My meter reads inductance, can I use it to determine if I have the right number of turns to achieve the 17uH?

[Roland Jacques]

Now were getting our money's worth out of this guy. LOL. Thanks, Phil.

Yes sir, I say we should double his salary.

I assume that MMW performance quotes are brute force readings ( DC battry without PWM's).
I have used 4 differnet meters (cheaper type) and all had differernt voltage readings 11-15 volts. so IMO you can't get to excited about some folks MMW quotes. I would be nice to be able to calibarte volt meters at home.

[canpower]

So, how do we smooth the current??? Pretty easily, it turns out. Using an power inductor and a single high current diode, we can manage to smooth the current to a pretty fair degree. However, there will be SOME additional power loss in the inductor and diode, but this should be minimal when compared to the gain by using this method.


I've got a question regarding the addition of an inductor to the circuit at the output of the PWM module. I think I already know the answer, but I have to ask anyhow.

Will the addition of this inductor create the need for some kind of protection at the output of the PWM module against a back EMF inductive kick of some kind?

I know the mosfet chosen to do the job should be beefy enough in the first place to handle such catastrophies, and it probably isn't enough voltage to worry about (I'm used to building tesla coil and EMP type devices with mosfet drivers!) but I just wanted to make sure, since we are actually altering the PWM module design when you think about it, not just "attaching" an extra component or two to the electrodes really.

Does this make any sense to anyone, or do I need to go back to school after all these years...hehe.

Chris ;)

[Helz_McFugly]

@hg2
youve got mail.

[Philldpapill]

@biggy boy #43
You might be able to get by with using the #18... There are two factors to consider when designing a toroid... The first is how much flux the toroid can take before it saturates... This is basically how strong the field produced by the wire can be, before the core stops acting like a ferromagnetic material... I'd have to do some serious thinking about the layout using the #18 wire. It is possible to wrap the core, say 100 times, with the #18 wire in one quadrant of it, then get another wire and wrap that 100 times in another quadrant, and so on. Effectively, you would have a bunch of these 18 guage wires wrapped in parallel over the core. It's basically the same thing as making a bundle of 18guage wires, and wrapping the bundle around the core as if it were a 10gauge wire like mine.

If you want, I can just wrap the cores for you. I've got plenty of 10guage magnet wire, and some special 12guage square magnet wire(but that's for my coilgun toy!). The cores are about $4, and the wire is about $5 for the 14' needed for each. All in all, I'll do it for free, except for materials.

Oh, and by the way - the inductance I have is 7,500 micro Henry's, or 7.5milliHenry's. 7.5uH is about the inductance of a straight piece of 15' of #10 wire.


@canpower #45
The addition to the PWM isn't ONLY an inductor... It would also be a high current diode in antiparallel with the PWM output terminals. This diode would drop the voltage spike when the mosfet turns off. It basically turns your average PWM into a buck converter, which should increase efficiency.

[biggy boy]

Phil I'm going to wait until you have finished your setup, and hopefully you will be able to do a before and after test. This way we can see if it will allow you to make more HHO at a cooler temp.

I understand what you are doing and understand how it will work.
But I'm still on the fence for now as to whether the HHO cell actually will produce more gas at constant current or if it likes the pulsing spiking current!?!?? There is somthing about that pulsing/spiking current.

I don't want you to spend your time making me one until I get off the fence, I may jump off the other side:) But I do really appreciate your offer!! :cool:
I may take you up on it at a later date.

Glen

[Philldpapill]

There could be something to the pulsating current, but IMO, I seriously doubt it... I really do think that it's a rumor sparked from bad measurements. I think early on, someone went "See! Look! All that gas and my current meter only says 2A!". I think it's more likely that someone made a measurement error, rather than actually making a ground breaking discovery...

On the other side, I'm not saying you can get MORE HHO per amp, but you CAN push more current into your cell without it overheating, by using this method. You aren't going to surpass the electron-hydrogen molecule ratio, but you might be able to increase the efficiency of your cell, and that always results in more HHO per watt.

[Philldpapill]

UPDATE:
I just thought you guys might be interested in this bit of "news". I've been doing a ton of simulations today, and I think I've finally got some of the major kinks worked out on this new PWM system I'm designing.

Check this out: Assume you have a 0.1 ohm load(the HHO cell for instance), a 12V battery as your source, only a ---1mH--- toroid, switching at 25kHz, and running at 20% duty cycle... The input current is about 3.2A, but the actual RMS(nearly DC) current through the cell - A whopping 15.9A continuous.

If you muttered an expletive, I've been yelling a few today over good and bad results - mainly good. :D

Anyway, the point is, I think I'll be able to push ~75A through the final design(almost done), and still get nearly a 2-to 1 ratio of currents. In other words, I think I can get 75A for the output, while only using 35A-40A from the battery/alternator source. Cool, eh?


EDIT: This post sounds a little misleading, so I wanted to clarify... This PWM only maximizes efficiency - it DOES NOT put out more power than it takes in. The main point about this design, is that you can totally saturate your cell with electrolyet so that it has the absolute lowest resistance possible, while still being able to have a VERY good handle on current consumption, and VERY low power dissipation. The power dissipated at the full 75A load current, that would probably be about 50W. That may sound like alot, but at 40A and 12V input, that's nearly a 90% efficient PWM with minimal power dissipation in the cell(runs nice and cool).

[Roland Jacques]

Good thing you clarified that. I was going to call the OU police on you.

Up to now this sounded kind of similar to adding the capacitor that you spoke of before. But now it sounds like it could be much better.

[Roland Jacques]

So is this a Constant Current type PWM? Or could your PWM be controlled by a constant current controller like this http://www.3rdbrakeflasher.com/index.php?main_page=product_info&cPath=70&products_id=208

[Philldpapill]

The constant current PWMs are nice, but very simple. They basically watch how much current is going into the cell, and as the cell warms up and current increases, the PWM cuts back on the duty cycle. That's great, but does nothing for efficiency.

The PWM I'm talking about would not only have the same kind of negative feedback to control current, but it will also turn the harsh square waves, into a nice steady DC current. When you push DC current through the cell instead of high peak current square waves, the result is less power dissipated(heat). That's the heart of this PWM.

Make sense?

[canpower]

I've got a question regarding the addition of an inductor to the circuit at the output of the PWM module. I think I already know the answer, but I have to ask anyhow.

Will the addition of this inductor create the need for some kind of protection at the output of the PWM module against a back EMF inductive kick of some kind?

I know the mosfet chosen to do the job should be beefy enough in the first place to handle such catastrophies, and it probably isn't enough voltage to worry about (I'm used to building tesla coil and EMP type devices with mosfet drivers!) but I just wanted to make sure, since we are actually altering the PWM module design when you think about it, not just "attaching" an extra component or two to the electrodes really.

Does this make any sense to anyone, or do I need to go back to school after all these years...hehe.

Chris ;)

No comment on my questions? None at all??

[Helz_McFugly]

No comment on my questions? None at all??

nobody loves you http://www.mysmiley.net/imgs/smile/animated/anim_03.gif

[Philldpapill]

Sorry, canpower, I thought I answered that - maybe indirectly. There is a high power diode in there. It's a classic "buck converter" arrangement. Wikipedia has a good article on it. No other protection is need, IMO.

[biggy boy]

Phil hows the project coming along?

I tested out the Z.F.F. PWM I made this morning for the first time.
I ran a small Dc motor on it and it works.
I need to put it on a bigger load to really try it out.

Question for you.

I was able to adjust the speed of the motor with the duty cycle pot
and with the freq. adjust pot.

Does that sound normal for the Freq pot to effect the speed of a DC motor?
I know with a VFD drive running a AC motor that is how the speed is controlled. Is this also the case with DC?
I know with Ac the freq is how many alternating cycles per second.
But in this case using a PWM DC, is it pulsing on and of at a frequency too?

Then you add in the duty cycle:
The voltage is pulsing at a certain freq. while it is in the on duty cycle.
during the off duty cycle there is no freq. pulse?

Sorry for hogging your thread!!!

[Philldpapill]

Yes, biggy boy, that's normal. The reason, is that the motor windings represent inductors. An inductor "looks" kind of like a resistor as a function of frequency, but it's a bit more complicated than that. In this case, the "impedance" of the inductor goes up as the frequency goes up. So, when you are increasing the frequency, the current actually drops off a bit, resulting in a tad less torque, which results in a slower speed.

Ideally, you don't want to use a standard HHO PWM to control a motor. The inductance in the motor will cause voltage spikes on the mosfets, causing them to heat up and could possible make the PWM fail.

Duty cycle, on the other hand, causes a near proportionality relationship with current, so, the motor increases speed with increased duty.

[canpower]

Phil hows the project coming along?

I tested out the Z.F.F. PWM I made this morning for the first time.
I ran a small Dc motor on it and it works.
I need to put it on a bigger load to really try it out.

Question for you.

I was able to adjust the speed of the motor with the duty cycle pot
and with the freq. adjust pot.

Does that sound normal for the Freq pot to effect the speed of a DC motor?
I know with a VFD drive running a AC motor that is how the speed is controlled. Is this also the case with DC?
I know with Ac the freq is how many alternating cycles per second.
But in this case using a PWM DC, is it pulsing on and of at a frequency too?

Then you add in the duty cycle:
The voltage is pulsing at a certain freq. while it is in the on duty cycle.
during the off duty cycle there is no freq. pulse?

Sorry for hogging your thread!!!
Hi biggy boy, would you be willing to share the schematic of what you built? Is it one posted in this forum?

Also, what frequency SHOULD the electrolyzer be running at? Nobody seems to want to reply with a "specific" frequency, just a range. What is everyone running their PWM modules at? Is there a duty cycle, or just a square wave to the mosfet driver?

I seen plans where there were 3 different frequencies avaliable, via a 3 way switch. What are those frequencies, and why would you need to switch between them?
Thanks ;)

[biggy boy]

Canpower
Do you have Eagle the circuit board drawing software from Soft Cad?
If you do I can send you the whole file, schematic and board layout.
I want to test the PWM under a heavier load, before I offer up the board layout. I don't want to be giving someone a lemon. So far it looks good.
The schematic is a copy of Zero Fossil Fuels schematic from his site. I had to redraw it out to use it to creat the board layout.

here's the finished board before I put it in the box.

http://i107.photobucket.com/albums/m297/biggy-boy/finishedback.jpg

http://i107.photobucket.com/albums/m297/biggy-boy/finishedboard.jpg

[canpower]

Yes, I have eagle installed ;)

I would be happy to receive your schematic.

Do you have this design up and running successfully, or is this just a new design?

Thanks again,
Chris ;)

[biggy boy]

Yes, I have eagle installed ;)

I would be happy to receive your schematic.

Do you have this design up and running successfully, or is this just a new design?

Thanks again,
Chris ;)

Yes it up and running, had it going yesterday for the first time. Just need to test it with a bigger load. What's your email I'll send the files?
You can have a look at it.

[Helz_McFugly]

does anyone use "autocad desktop 200X"? and will my autocad open your eagle files?

[biggy boy]

does anyone use "autocad desktop 200X"? and will my autocad open your eagle files?

Ill try exporting it as an autocad hold on!!

Tried it can't export as AutoCad

[Helz_McFugly]

I fried my PWM last night. a lose hotwire touched the groud terminal and it no more worky. so now Im back to controlling current with e-lytes :mad:

[biggy boy]

I fried my PWM last night. a lose hotwire touched the groud terminal and it no more worky. so now Im back to controlling current with e-lytes :mad:

That sucks!
Did you open it up to take a look?
what went the Mosfet I guess?

[Helz_McFugly]

yip. mosfets dead. can you get them at radio shack? are they cheap? and which ones should i get? Its Zero's double mosfet PWM. I can put them in if I knew where to get them.

[biggy boy]

yip. mosfets dead. can you get them at radio shack? are they cheap? and which ones should i get? Its Zero's double mosfet PWM. I can put them in if I knew where to get them.
Phil will be a better person to ask for the reason of location.
We don't have radio shacks here in Canada anymore Circuit city bought them out and renamed them the source. and they suck now!!

You should be able to use any N-channel Mosfet rated at 30 volts or higher, also rated for the current you intended to run. I ended up using three in mine in parellel. they are rated at 200 volts (overkill big time) and 30 amps each.
I'll post a picture soon!

Glen

[Helz_McFugly]

I went to radio shack for lunch, I walk in. "where are your mosfets?" mos what?
I swear these people that work at radio shacks are hired from special ed halfway houses.

[biggy boy]

If you want to get ambisius you can add more Mosfets, but you would need to run individual resistor leads. to each one. Just make it the same length as what he used. On mine it is the wires going to the bottom terminal of the Mosfets. That is the source! The other wires can be jumpered from the other Mosfet. Also run a new drain wire from each drain to the output terminal on the box. Make sense? :p clear as mud?


http://i107.photobucket.com/albums/m297/biggy-boy/PWM1.jpg


http://i107.photobucket.com/albums/m297/biggy-boy/PWM2.jpg


http://i107.photobucket.com/albums/m297/biggy-boy/PWM3.jpg

[Helz_McFugly]

Here is mine. they put the terminals on strange. the - input and + are on one side and the - output is on the other.
http://www.hhoforums.com/attachment.php?attachmentid=1371&stc=1&d=1255033728
http://www.hhoforums.com/attachment.php?attachmentid=1372&stc=1&d=1255033771

[biggy boy]

I think I would just replace the two Mosfets.
Is there any sign of damage to the Caps or anything else on the board.
On the big electrolitic cap either of the ends bulged at all?

[Helz_McFugly]

no, im pretty sure its the mosfets

[biggy boy]

http://www.globalspec.com/local/3455/TX/Houston

[artnesmith]

I've new here, but noticed a lot of information on pulsers in general. In my limited experience it seems pulsers react differently depending on the parameters such as plate spacing, surface area, electrolyte strength and configuration. For example, a dry cell with 4 neutral plates is more efficient than the same size dry cell utilizing 3 neutral plates without a pulser. However using a pulser on the 3 neutral plate dry cell, if you adjust the duty pot so that voltage between the cells drops to around 2.5 volts per cell, then the 3 neutral plate cell goes up to about the same efficiency as the 4 neutral plate cell. This having a spacing between plates of approximately 1/16th of an inch. The 3 neutral plate design operates great with weak electrolyte, have an advantage for some people there. But what about using the pulser on the 4 neutral plate cell? Hard to get great improvement since volts between the cells already around 2.5.

I am only just learning the ins and outs of adjusting a pulser for performance. Hard to figure all of this stuff and the different parameters. Can be confusing for sure. Any input most welcome. ;)