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Thread: Just asking, DOES A PWM REALLY DO ANYTHING?

  1. #1
    Gary Diamond Guest

    Default Just asking, DOES A PWM REALLY DO ANYTHING?

    I can't understand why anyone uses them, if you want to cut down current add more cells. i can't possible see how adj the freq. and pluse width duty cycle does anything Please prove me wrong.
    Gary diamond
    Last edited by Gary Diamond; 02-15-2009 at 06:14 AM.

  2. #2

    Default

    Gary,

    A PWM comes into its own when you forgo the "two tsps of KOH for the amps I want to pull once its warmed up" and you use a maximum concentration electrolyte, use the PWM to control amp draw and increase the efficiency of your cell due to the lower resistance in it.

    I increased my MMW by a whole point with a PWM on my last cell.
    2006 Dodge Ram 4.7L - 16.5 mpg stock
    My thread Painless Experiment in HHO

  3. #3
    Gary Diamond Guest

    Default

    Quote Originally Posted by Painless View Post
    Gary,

    A PWM comes into its own when you forgo the "two tsps of KOH for the amps I want to pull once its warmed up" and you use a maximum concentration electrolyte, use the PWM to control amp draw and increase the efficiency of your cell due to the lower resistance in it.

    I increased my MMW by a whole point with a PWM on my last cell.
    If you say so, if the resistance is to low add another cell set, if your KOH is to strong cut it down, it just seems to me to be a fix for something broken, that should not be broken.

    Gary Diamond

  4. #4

    Default

    You're still missing the point, Gary.

    Let me explain this a different way.

    If you use a 28% KOH solution, the resistance per cell gap will be X. If you use a much weaker solution, your resistance per cell gap will be Y.

    Y is a higher resistance than X, therefore, when Z amps are put through the two different setups, X will produce more HHO at the Z amps than the non-pwm setup, due to the lower resistance.

    Another benefit is cell warming. Let's say your target draw is 20 amps, you might add two tsps KOH to achieve this (for example). When your cell is cold it may draw 10 amps and move up to your 20 target as it warms. With a PWM you are running at your target amps from cold to hot. In other words, your required LPM is there from cold start.

    In a small output setup, a PWM may be overkill. But, in a setup where high output is required, the benefit of a) hitting your needed LPM out of the gate and b) achieving that LPM with less amp draw is welcomed.
    2006 Dodge Ram 4.7L - 16.5 mpg stock
    My thread Painless Experiment in HHO

  5. #5
    Gary Diamond Guest

    Default

    Ok I will agree with you if your set up starts to run away on heat, it would be good to limit current flow.
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    I also feel if the HHO generator is designed correct, and placed in the front with cooling fins, there would not be any need to add a device to fix a problem that should not be there in the first place.

  6. #6

    Default

    Quote Originally Posted by Gary Diamond View Post
    Ok I will agree with you if your set up starts to run away on heat, it would be good to limit current flow.
    -----------------------------------------------------------------------------------------------------------------------------
    I also feel if the HHO generator is designed correct, and placed in the front with cooling fins, there would not be any need to add a device to fix a problem that should not be there in the first place.
    I agree 100%, a PWM shouldn't be used as a band aid for bad cell design. It should be used for higher efficiency and consistant amp draw from startup to shutdown.
    2006 Dodge Ram 4.7L - 16.5 mpg stock
    My thread Painless Experiment in HHO

  7. #7
    bigjim56 Guest

    Default

    I hope I got this right...

    So if you start out the system w/a PWM running at 20 amps, it will not only give the 20 amps production from the start (no warm-up needed), but the higher strength electrolite offers greater production due to the lower resistance of its solution. Sounds like the maximum strength solution is the way to go.

    Who's got the economical PWM's for sale?

    Also, I believe this concentration (28%) is good for temperatures down below 20 degrees. Lower temperature's require alcohol addition, what affect would this have?

    bigjim56

  8. #8
    SmartScarecrow Guest

    Default

    Quote Originally Posted by Gary Diamond View Post
    Ok I will agree with you if your set up starts to run away on heat, it would be good to limit current flow.
    -----------------------------------------------------------------------------------------------------------------------------
    I also feel if the HHO generator is designed correct, and placed in the front with cooling fins, there would not be any need to add a device to fix a problem that should not be there in the first place.

    I think your core question is, "will a PWM make more gas than without a PWM" ... the simple answer is no, it will not ...

    however, in operation, we find that these devices tend to ramp up production as they warm up and can if not controlled, pull more power than is available which causes problems and blown fuses and such ...

    you are correct that if your design is very precise, and you elyte concentration is very precise, you can control your device without the use of a PWM ... but doing this is a pain in the butt ... so the PWM gives average Joe an easy way to "dial in" a desired level of performance without having to be so precise with the other factors ...

    as a real world example, I am running small engine tests using a cheap little Chinese 1500w gas powered generator ... I am so close to getting the darn thing to self sustain that I decided I wanted to give it go even though I knew going in that I was a little shy of the mark ... having the PWM let me tweak my electrolyzer to a very precise setting so it not try to pull more juice than the little generator could put out but grabbed every bit of what it was capable of ... only with PWM could I control it that fine where I got every freakin' watt of power I could out of that little genny without popping its breakers ...

    did that help to explain it for you ?

  9. Question

    Quote Originally Posted by SmartScarecrow View Post
    I think your core question is, "will a PWM make more gas than without a PWM" ... the simple answer is no, it will not ...

    however, in operation, we find that these devices tend to ramp up production as they warm up and can if not controlled, pull more power than is available which causes problems and blown fuses and such ...

    you are correct that if your design is very precise, and you elyte concentration is very precise, you can control your device without the use of a PWM ... but doing this is a pain in the butt ... so the PWM gives average Joe an easy way to "dial in" a desired level of performance without having to be so precise with the other factors ...

    as a real world example, I am running small engine tests using a cheap little Chinese 1500w gas powered generator ... I am so close to getting the darn thing to self sustain that I decided I wanted to give it go even though I knew going in that I was a little shy of the mark ... having the PWM let me tweak my electrolyzer to a very precise setting so it not try to pull more juice than the little generator could put out but grabbed every bit of what it was capable of ... only with PWM could I control it that fine where I got every freakin' watt of power I could out of that little genny without popping its breakers ...

    did that help to explain it for you ?
    SSC,

    Are you attempting to run the small engine entirely on hho or are you supplementing the gas?

    If you are shooting for 100% hho, why?

    BoyntonStu

  10. #10
    SmartScarecrow Guest

    Default

    Quote Originally Posted by BoyntonStu View Post
    SSC,

    Are you attempting to run the small engine entirely on hho or are you supplementing the gas?

    If you are shooting for 100% hho, why?

    BoyntonStu
    100% HHO .. runs fine ... been doing it since late last year ... so far, no damage to the cheap Chinese engine ... I am still not doing it well ... my delivery system needs much improvement ... and there are modifications to the piston engine I need to try to see what works best ... so far, have tried a milled down head to increase compression ratio to 13:1 and various timing and ignition mods ... I have also documented the volumes of HHO required to run the engine under various loads ... its all just pure research and data acquisition ... the understanding is goal enough for me ...

    EDIT: duh, should have said late in 2007, not last year ... its already next year ... and actually, I was running a little B&S 2.5 hp engine on HHO 5 years ago ... so this is nothing that new or exciting ... folks been tinkering with this for quite a while ... a lot of people are doing it now ...
    Last edited by SmartScarecrow; 02-18-2009 at 04:29 PM.

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