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PWM & high current

Discussion in 'Alternative Energy' started by electrookie, Aug 28, 2009.

  1. bryan1

    bryan1 Well-Known Member

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    OK guys I have gone right thru this thread and deleted near everything that was swaying this topic. As shown some members are really trying to help the OP out so rather than delete the whole thread it will keep going and kept on topic.

    If some members want to flout this forum go ahead and try me as the next time I see any anti HHO claims, etc which only spoil the forum image, WILL RESULT in an infraction.

    I am doing my best to improve this part of the forum and the time has come to keep the topics in the Alternate and Renewable forums on topic and if some members want keep going there is the chitchat forum to go do it in.


    It really is a shame for me to have say the above measures as 99% or more of the members of this forum are Adults.

    Regards Bryan
     
  2. be80be

    be80be Well-Known Member

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    Mr RB Like i said before his circuit don't look like it was made for high amps

    And I think your right
    And like I said we need to look at the cel how it is made.
    There a lot of things that could be done with the cel but one would need to take great care not to make something that could hurt them.

    I've seen where you can split the hydrogen and oxygen in to there own cel
    which would make fuel grade hydrogen and pure oxygen not to be played with.
     
  3. electrookie

    electrookie New Member

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    Loosing the cap then...

    Now you see... this is excellent sir. Your ?'s provide answers I had no idea I was searching for.

    I will try to find a standard push-pull FET driver to use as you point out. When I get answers like these, I do like the challenge of figuring out what your talking about, and I will ask you later on if what I find is in fact what you are talking about.

    OK then. For the 60 + amps, I have added a 2nd mosfet in parallel with the original one. I figured it would spread the work over 2 of them and help performance.

    I use the caps because that is what the designer put in the circuit. But now that I think of it, the earliest build of this circuit I did was without the cap. And if I recall correctly, it worked just fine, at least at low currents. If the cap is not necessary, I will get rid of it. And this will help save considerable space as well as few $'s.

    Originally, there was a problem with the 10 ohm resistor burning up. I thought he added the cap to help with this. He explained it as the power wires to the PWM need to be short length because putting the
    PWM too far from the battery caused an induction into the wiring that burned up that resistor. Originally, I put in a 2 watt 10 ohm resistor to deal with this problem & it seem's to help, but it does still get quite hot. Now that I have access to your knowledge :), I know there is a way to resolve this resistors problem better than putting in a bigger resistor, I just don't know what that answer is.

    See, ZFF tells us rookies things we do not understand. He talks above our heads like he was talking to one of his peer's, which very few of us are. And trying to get him to explain things in laymen terms is worse than pulling teeth from a lion. Its frustrating at times. But now that I have found you all, my frustration is taking a back seat as I learn from your teaching's. Bless you guys & I can not say thank you enough...

    And yes, the goal with the controller side is; as you pointed out. Fortunately I do have some good test equipment. 2 o-scopes, and a variety of different meter's covering just about everything I need to examine. Sometimes, I am not sure just what some readings are telling me, but at least I can get the readings and watch the signals on the scopes.

    Watching those shows about some people and their energy systems is impressive (to me anyway) and I agree, they leave you hanging for the details too often. When I catch such a show, I try to take the time to make notes so I can look into the given subject further using the web resources. And that can get frustrating some times as well because when I find answers, I do not necessarily understand them completely. I'm not a moron, just not exposed to much of these fields with any formal education. But knowing where to go for answers is valuable, and this forum has proven that.

    So the bottom line is I should dump the large cap all together.

    Does 2 mosfets really do any good, or can I just use a single one with much higher rating's?

    And does the 2 watt 10 ohm resistor need changing (component or circuit wise) to address the problem of "induction"?

    I am appreciating this forum more and more each day. Its wonderful having access to knowledge and experience of others to help me along. By the time I get the next one of these designed (with all your inputs & recommendations as the guide), I just may wind up with a circuit that does the job very well and others can gain this information for their own circuits. I look forward to this very much as this has been a problem for too long and I was lost on fixing the issues.

    So to you guru's that are helping me, I salute you:)
     
    Last edited: Sep 2, 2009
  4. dave

    Dave New Member

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  5. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    I buy industrial IGBT blocks on eBay all the time. They have good used take offs in about every size and configuration you could ask for. Plus a 600 amp 1200 volt unit takes a hell of a lot of abuse before giving up!

    The last time I purchased that size I got 5 Infinion (FZ600R12KE3) 600 amp 1200 volt IGBT units for $125 including shipping. Brand new too! ;)

    Being voltage controlled they are easy to set up with a basic FET/IGBT driver IC like the IR2110 or one of its many cousins.:)
     
  6. electrookie

    electrookie New Member

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    emmissions are reduced...dramatically

    I don't know how I missed this one but I would like to reply.

    When an HHO system is placed on our modern vehicles, it MUST be properly "calibrated" for said use. And I refer more to modifying the ECU than the HHO system. When the ECU sensors are properly enhanced to allow for the cleaner & faster burning of the gasoline, the resulting emissions are dramatically reduced. If one does not do these enhancements, then the ECU will go into closed loop operation and simply DUMP gasoline into the intake in copious amounts, resulting in wasted fuel and seriously bad emissions, amongst other things.

    So the bottom line here is that the emissions are even better than the 30 years of improvements the industry has made in this area.

    And using HHO in conjunction with other adaptations to a cars fuel systems, one can get even greater improvements. I have a friend who drove down to visit us the other day. He has one of those large Ford pick ups and he has added HHO and a few other things. The amazing thing of his system is that after driving 90 minutes to get here, he reached under the back end of the truck and grabbed hold of the exhaust pipe, with no burning of his hand. I was exceptionally skeptical when he claimed this was the case but I was not about to touch that thing, at 1st anyway. When he did it with no problems, I then grabbed hold of the exhaust pipe myself and it was quite warm, but I could hold on to it all day and not get any burns from it. I got out the temperature meter and we found it was at 120 F.

    Remarkable, to say the least. His other enhancements include a fuel additive, a magnetic device that clamps over the fuel line, extensive grounding of every part of the truck to every other part of the truck, and 2 others things I don't recall at the moment. He says he has a few more things to do to get the results he is after, and then he will give this information to the world. Apparently, most of these things are readily available "off the shelf" for anyone to buy. He is just using as many of them as he can find to improve his results. I won't cite his mileage claims here, because they seem like way to much to be possible, but I will monitor his claims closely because if he does have such a system going, I WANT IT TOO. OH yea, one of the other items is a performance "chip" he got from a company that makes performance enhancement chips for use with any car whose owner wants to improve performance.

    People what all this proof. I have no problem with that. But when they are shown the proof, many will not accept it. All I can tell them is if they want to know the reality of any such technologies, they need to do the honest, deep digging research to find the truth. Those who throw out their rejections out of hand are just missing out.

    I have been receiving so much help from the people here (the ones who are not grinding ax's) that I feel like I have finally found a place where I can get help with my electronics efforts. And I have. Thanks to you guys, you know who you are..
     
  7. electrookie

    electrookie New Member

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    Thanks moderator...

    Thank you moderator. I am trying to get, & am getting much of, the help I seek. So I can not agree more about staying on topic.
     
  8. electrookie

    electrookie New Member

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    Igbt...

    Are you saying that using an Insulated-gate bipolar transistor in place of the mosfet is what you would consider? I'm liking this idea as the mosfets are hard to work with and apparently not too efficient in this application.

    If you spent $125 for 5 of them, I gather they can get very expensive? I will go look into these right now. Hopefully smaller ratings will be considerably cheaper.

    Wow, you guys bandy about these various idea's and I just sort of "pick up on them". It works for me, especially if I can get a better mouse trap out of all this. My brain has plenty of room for more learning & I look forward to it :):):).
     
  9. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    I do have a comment about your friends exhaust system though. I have a 1999 Ford F-250 super duty with the triton V10 and I have it chipped out also. I however have a home designed dual fuel conversion for propane on it.
    When running propane the ECM will log two error codes for each O2 sensor. Failed to reach operating temperature and lean burn condition.

    Propane burns to cool and to clean for the O2 sensors to register it properly plus propane also has a naturally leaner A/F ratio.
    What that equates to is the exhaust temperature is much lower and I too can grab my exhaust system without getting burned after a normal drive when running propane. Even after a long hard drive pulling my big flatbed trailer loaded to 10000 pounds I still cant fry spit on the end of the exhaust pipe. My IR thermometer says its about 200F at that point. On gasoline I can do that right after a normal trip from town IR reads around 230 F.

    The thing about different fuel use is different fuels dont have the same A/F ratio as gasoline. Just because the new fuel may burn at a 16:1 A/F ratio doesn't actually mean its too lean for the engine. In fact it may be far better for the engine! Gasoline at that A/F ratio does damage but if diluted with a another fuel it can have no bad effects.

    If you put a properly regulated propane flow into any vehicles air intake it too will have a noticeable drop in fuel use and exhaust temperature!
    The more propane the less gasoline is used. However there is a tipping point where the A/F ratio goes out of the vehicles computers valid operating range an then it goes into the open loop mode and things get worse instead of better.

    The big IGBT's I referred to in my earlier post retail for around $300 - $400 new. So $20 each is not a bad in my opinion! :D
     
  10. Mr RB

    Mr RB Well-Known Member

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    Hi Electrookie, and thanks Bryan1 for tidying up the flames and allowing the thread to continue. If there's one thing the amatuer hydrogen sector needs it's to get back to real facts, careful measurement/testing and refinement of hydrogen technology not get bogged down in car argument and personal opinions.

    Electrookie, I think 2 FETs (or more) is definitely the way to go. You reduce the resistance losses from connection etc and increase the ability of heat transfer out of the FET silicon to the heatsink etc so the FET silicon runs cooler and more efficient. Most high current switching designs use many FETs in parallel.

    I'm not sure why your 10 ohm resistor runs hot. That is what i was saying about testing. Measure the DC voltage on the resistor when running, you can then calc the current passing through the resistor, and the power (heat) wasted on the resistor from ohms law.

    I would remove the large output cap altogether. At least for now, for testing. You have 2 oscilloscopes and some multimeters, which is not bad you are well on the way to having a good test setup.

    Please don't think that I'm some type of hydrogen expert, I fiddled with hydrogen electrolysis when i was young (late '70's) and found that 1. it's very easy to use electricity to separate water into H and O, and 2. it's quite hard to do it EFFICIENTLY, with very high percentage of the input power going into electrolysis and little converted to waste (heat).

    Unfortunately there don't seem to be many people with good hydrogen/electronic skills talking about it, the 2 camps seem to be the overly enthusiastic and sometimes misguided amatuers and the rare uni/pro researchers keeping their mouths shut and their secrets well... secret. :)

    Here's how I would go about it;
    1. Forget 100 amp setups for now, build a smallish research setup of maybe 10 amps in a nice clear acrylic container. This allows much cheaper and faster changes to the cell and the control electronics, is easier to see it operating, it will be easier to measure, also it won't blow up as much and IF the FET's blow etc it will be much cheaper and quicker to fix.
    2. Set up with your oscilloscopes and meters so you can measure the actual electrical power going into the cell, thats the most basic thing you need to know...
    3. Test the HEAT going into the cell, this is my personal method for testing it's efficiency and works pretty good. Heat the cell using a known power source and see how hot it gets (above ambient temp) for any given heat power input in watts.
    4. Now when operating the cell you know how much electrical power is going into the cell, and how hot it gets (ie a thermometer) tells you how much of that input power is being wasted as heat, the remainder is your conversion power so you can instantly and easily measure the efficiency of your sell in testing.
    5. Start testing electrolytes/plate design/frequency/waveform/liquid circulation and any other factors you can think of, and start refining the efficiency of the conversion and the longevity of the plates etc. There is a huge amount of research to be done and not enough people doing it. :)

    Some of the main issues are plate separation and clearance. If the plates are too far apart the cell resistance is high and a lot of energy is wasted as heat. But if the plates are too close together they quickly get bubble fouled with reduces the plate contact with the liquid and it reduces the output and causes other problems like plate hotspots and increases heat buildup.

    I like your idea of using reversing DC once the bubbles build up to reverse the plate charge and release the H and O bubbles. You could experiment with that. My personal thoughts are about exploiting the mechanical resonances, even purposely building the plate mounts to allow flexion of the plates at a resonant freq and then tune the freq of the electrical input to vibrate those plates at the resonant freq and clear the bubbles from the plate surface in a way similar to an ultrasonic cleaner bath. If you could shape the plates to force an UPWARD flow, even better still, to get the gas to the top of the cell quicker and bring cool fresh liquid in in a constant circulation. Since you have access to oscilloscopes you can hook a pickup up to a plate, rap it and see the waveform (ie measure resonant freq) on the scope.

    Anyway that's my thoughts on the actual electolysis process; converting the electrical input energy to a useful gas fuel at (hopefully) decent efficiency. I'm not at all interested in the whole "HHO/gasoline car fuel ecomony" side as it always seems to turn into arguments and I'm a motorcycle guy anyway. ;)
     
  11. electrookie

    electrookie New Member

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    O2 & A/F Sensor enhancements

    For any mixing of fuels I can not speak on with any experience. With HHO, we use a circuit called and EFIE - Electronics Fuel Injector Enhancer - that provides an adjustable offset to the O2 sensors so the ECU reads what it expects to read. These work very well. For the A/F sensor, there is a very simple circuit for it and for other sensors like the MAP, MAF, IAT, and others.

    The attached file can be found at many sites, it is a very good description of the circuits used for these sensors.

    But, I quit using these at all recently because the HHO Performance Chip takes care of all the sensors and is so much easier to install, just 4 wires.

    For the IGBT's, I can see where the deal lies for a $400 part at $20 each. I went looking for these and found they are available for much lower currents and voltages, and seem to have better characteristics than the mosfets, and of course not that high priced. I ordered a few and will try them out.

    This keeps up and in a few weeks, we will have a totally different circuit that does the job way better. I like it...
     

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  12. electrookie

    electrookie New Member

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    Lots of good info

    I appreciate all the info here. A lot of refinement does need to take place and your so right about 2 different camps of HHO & electronics. Not too many people in both these camps combined that are available. Myself, I am a rookie in both these camps, but thanks to you and others here, I am learning fast.

    And as a rookie, I will show my lack of knowledge again and ask when you say use FET's, are these the same as IGBT's or a different animal? And which would do better in this situation in your opinion?

    Others have said the cap is not needed, so I will dump those as well. I am playing with a whole new design based on the LM3525 PWM IC for the control and IGBT's (or FET's) for the cell drive circuitry.

    I am taking your advice to heart and instead of just building what anyone out there puts out, I will get down to some serious investigation of the electronics and the cell design.

    And as far as I know, what you said:

    1. it's very easy to use electricity to separate water into H and O, and 2. it's quite hard to do it EFFICIENTLY, with very high percentage of the input power going into electrolysis and little converted to waste (heat).

    is still true today. But I don't see where that is a problem because the power to drive the system is coming off the vehicles alternator and batteries, so the efficiency does not seem important to me. The end result, better gas mileage and performance is the goal and I get that with these systems. So for my money, this is a very good way to go. And this technology does not require purchasing any other alternative fuels at all, just add water...:). Why pay for propane or LNG when I can do this?

    It has been a serious learning curve for me and I love to learn. I am always reading, playing with "things" but I have no degree's from higher education. I considered it earlier in life, but not anymore. I know enough about may fields just enough to be dangerous, so I am told. A Jack of all trades, master at none kind of guy. This has advantages and disadvantages. But I am not going to complain about my life choices, rather, I embrace them and try to find a way to learn more of any given subject that gets my interest. This HHO thing has got my interest big time. And now that I have found you guru's out there that are willing to help this "Jack" accomplish something new, well, I am tickled to death by the fact you all do offer so much advice. With your continued support, I feel like I can get the "Cats Meow" for the electronics side of this project. And again, I can't thank you guys (ladies too if that applies) enough.

    Back to work, but I am going to take a break and make a checklist based on your advice of how to proceed. I'll let you know what I find and probably ask you what it means...:)
     
  13. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    We just want to build one that works but are smart enough to let someone else do all the work in the whats wrong and whats right part first. (cheaper for us you know!) :p:D;)

    I am just glad to see a person trying this from a more realistic and scientific approach. Its what private AE and non conventional fuels research needs! :)

    As far as IGBT's, they are controlled by voltage just like a Mosfet but have the power and current control characteristics of transistors which gives them much more resiliency. When ever I rebuild a switching power supply for a welder or plasma cutter or some other high powered device I will replace the power Mosfets with IGBT's whenever possible. They have higher voltage and current ratings in the same package size and are cheaper yet take far more abuse.


    You wouldn't have a working schematic for a O2 sensor recalibrator would you? :)
     
  14. electrookie

    electrookie New Member

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    Different Circuit Here

    Hi my favorite Guru's. I am not sure if I should start a new thread here. The ?'s I now have are about a different circuit that I have been wanting to get together (have some of it together now) that is still for my HHO system, but not the PWM circuit.

    So I will blaze on and you all let me know if this is a new thread.

    This circuit flow chart attached here, is for the purpose of turning on a circulation pump for my HHO system, but in 2 different situations.

    Condition 1) If the engine is off (the HHO system is also off), and the temperature gets towards freezing (35 F, I am setting just a bit above freeze), this pump is to turn on and keep the fluids flowing till the temp rises again, or the engine (and HHO cell) starts. I have this temperature circuit designed around the LM35 IC and it works fine.

    Condition 2) With the engine started (HHO system starts at same time), the freeze pump circuit is turned off and a circulation pump circuit kicks in. Freezing is no longer an issue as cell will heat up. This circuit is also designed, using a 555 timer IC with very short duty cycle. Its job is to keep the fluid flowing to the cell by turning on for a short period of time, then off for a long period of time. I have yet to determine these time frames. The idea is to keep the fluid in the cell at a steady level. his has been an issue because as the plates heat up, they get to the point the cell produces HHO in a pulsing stream, per say, because the electrolyte gets pushed out the intake.

    The constant current PWM helps manage the heat very well, but even at lower controlled heat, this problem still exist. I have put in a one way valve on the intake and that helps, but the gas still prevents more flowing in when the pressure in the cell builds up to some given point. I have also greatly increased the size of the exhaust port of the cell to attempt to get more gas out faster, and that has helped. But the issue still remains.

    In the circuit shown, the AND gate is pretty much where I am hung up at. After that, the relay that is controlled by said AND gate will provide the 10Vdc (from a 7810 regulator circuit) to one circuit or the other depending on the conditions 1 & 2 above. From there, I am fairly confident the rest works fine, at least it has on the bench so far.

    So my ?'s are:

    1) Running a small power relay for long periods of time, is that any kind of problem or should I consider a latching relay circuit of some sort? Perhaps even a solid state relay?

    2) The AND gate, I know I can't stick a TTL or CMOS AND gate IC in there to do the job, so I am asking if any of you know, or can think of, some kind of..... I guess it would be an Analog AND gate?

    I wish I could spend all day watching for your all's reply's, I kinda feel like a kid on Xmas morn, wondering what gift's are coming. And your help IS a gift to me and I respect it as so.

    And as you can see, I am learning the electronics slowly, but learning!!!:D There are multitudes of sites with circuits listed and when I can, I dig thru them looking for "cool" circuits, if not for circuits for a specific job. That's how I learned to use the 555 in said duty cycle config. I used. And that's how I learned about the LM35 IC as well.

    I am aware the 555 has been around for longer than some of you fellows, but it is still a good chip and is simple to use. The LM35 is a new thing for me, I was going to use thermal couples, but it look's like a better choice. And the application notes pretty much give the circuit in full. Just have to determine the values for the temp's needed.

    But these do not mean I am not open to your suggestions with these either. I certainly am, but I don't want to pester anyone either and I feel I should do most of this work, not just ask for you guys to design something for me. That would not be right as far as I am concerned.

    Back to work, but I will log in here as often as I can looking for those presents...:D:rolleyes::confused:
     

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  15. electrookie

    electrookie New Member

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    Update on Analog Gate Circuit

    I got to thinking an AND gate is not the answer here. I went searching for a circuit and found a variety of options. In the attached file, I show 6 circuits that may do the job. Out of the 6, I am thinking the ones labeled Circuit C & Circuit F are the best of them. I think Circuit F is probably the best of them all, certainly the simplest as it only has the 2 MOSFETs.

    What do you fellows think of this?
     

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  16. electrookie

    electrookie New Member

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    PWM IC w/CV & CC

    Mr. tcmtech, your recommendation for using an PWM IC for the control circuit of the constant current PWM has had me on a quest to find one that may be just right for this. The attached is a Fairchild IC, FSEZ1216 that has caught my attention. If I may inquire, what do you think of this one?

    Anyone else is invited to throw in their comments & suggestions as well...:rolleyes:
     

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  17. be80be

    be80be Well-Known Member

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    Just get you one of these and the circuit you have will will be able to dump the amps into your cell[​IMG]
    Just one thing do you put salt in the water not much just a little.
    If you put salt in the water it will make HHO faster just don't over do the salt
    and if the water turns green dump it with a gas mask on because salt turned chloride ions into poisonous chlorine gas.
     
    Last edited: Sep 3, 2009
  18. tcmtech

    tcmtech Well-Known Member Most Helpful Member

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    There are so many PWM IC's that what ever you find thats simple and easy to work with for you is probably going to work.

    I just used the old LM3525 IC as a reference point being its been around for a long time and is very versatile being it can run in a number of ways and also has built in current feedback capabilities.
    As your probably finding there are also loads of 8 pin IC's with the ability to do what you need as well.

    As far as the actual switching devices what your comfortable with is up to you as well. I work with industrial electronics and of course that means I have buckets of used industrial switching devices to play with. ;)
    As far as when doing experimental stuff I am rather partial to gross overkill on the prototype power handling devices. Its pretty hard to kill a 1200 volt 600 amp rated IGBT with a 12 volt system! The odds are one of those could replace your starter solenoid without too much trouble! :p

    Plus it really looks cool to your buddies who think a TO-247 package device is big.:D
     
  19. cr125r847

    cr125r847 New Member

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    Will this circuit solve your AND problem?
    You are already using one relay in your schematic so you will just need to add one more to make it work.
     

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  20. be80be

    be80be Well-Known Member

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    I been thinking about this all night the Op said
    That would take a h-bridge to hook your cel to.?

    If you really wanted to use pwm to shake the cel I would use a small pic like 12f683
    you could easily change the pwm speed

    The pwm ic the op posted has a fixed pwm of 42 khz not much options for testing.
    The one TMC pointed out has much better control 100hz to 500khz.
    I think i would go with the lm3525 that way you could test to see what pwm speed works the best.

    Really I would use the pic and make this a low part count affair
     
  21. Mr RB

    Mr RB Well-Known Member

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    I get your point. The absolute efficiency of the electricity to gas conversion is of great importance to someone using Hydrogen for alternative energy storage use, ie after paying big $$ for solar setups etc they don't want to waste a big chunk of that daily energy in the conversion process, they want to convert the most % possible from electricity to a usable gas fuel. For your automotive use knowing the cell efficiency is not as critical, but it is still one of those things that separates the pros who KNOW what their cell is doing, from amatuers who just guess/pray and from crooks who just lie about what their cell is doing. ;)

    By doing real tests and measurements, and writing it up so others can evaluate and reproduce your work you become part of the SOLUTION instead being just another part of the problem. ie the problem being people making wild claims and scams that turn many people off even the mention of Hydrogen. Get every fact and figure you can from your setup, and then test and double test.

    Your controller has electrical power input, and outputs electrical power AND waste power (heat). You should know all 3 factors and have clear measurements.

    You cell has electrical power input, and outputs gas fuel AND waste power (heat). Again you should know these 3 figures and have measurements. Know exactly how many litres gas per minute your cell makes for a given electrical input in watts.

    These sort of facts and figures are sorely lacking on most of the HHO websites.

    Likewise if your goal is fuel economy then measure and record everything. Put a fuel flow meter on the gasoline line. Put a cheap datalogger on the car to measure fuel flow, speed, revs (and HHO output, cell input power) etc. Do back to back tests with the HHO turned on, then with it turned off on the same roads. Do tests with different amounts of HHO (ratio HHO/gasoline). Open up all your datalogger results to others so people can plot your vehicle's speed/revs etc against gasoline use etc. Get some smart respectable people confirming your findings and discussing ways to improve the tests or improve the HHO system.

    The closer you get to real research the better the payoff will be in terms of credibility and more people helping you and respecting your results.

    THAT'S why you make test gear and measure the efficiency etc of your setup. ;)
     

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