Many questions

[binderguy]

Ok, Jim here. It's time to show my lack of knowledge about most things electrical. It seems that to get the most out of a generator I will need a pwm so I thought I would ask some questions here to hopefully learn something. I posted the results of my lpm test and what happened after driving for a while so I won't go back into that here. My first question is, does a pwm have a circuit that will boost elect output so there is less of a load on the charging system or does it lighten the load by not having it constant. If you have a 30 amp draw at the generator do you still have a 30 amp draw at the battery? I am not real smart about things like transistors, mosfets, and so on. I do know that diodes are like a one way valve for elect flow and that is how alt current from an alternator is changed to dc for automotve purposes and that is about my limit of knowledge as far as electrical systems go. I do understand that pwms limit the amps so you don't get thermal runaway and that it will cause a higher amp load if you do. Also, if you have multiple cells with the individual cells in series drawing 20 amps each and the they are combined in parallell do you still have a total draw of 20 amps or would yout total draw go up by twenty for each cell you have hooked up? Any and all info on this is extremely welcome. Thanks, Jim.   

[Manta]

Imagine the pwm as an on-off switch. The length of time it is on (and off) is variable. This can be done manually (with a variable control on the dash,  or entirely automatically. Either way,  the current will be the same every time it is on. Assuming,  of course,  that you have already set the maximum current you want,  usually via the strength of the electrolyte.

Can't comment on the series-parallel thing with out knowing just how you will connect the cells.  But cells in series all pass the same current.  If you put them in parallel the current increases.

Hope this helps.

Manta

[Bob]

I look at a PWM as being a square wave of 12vdc  on and off very fast
and because its not ALWAYSE on...it draws less current than you would normially draw...so its easier on the charging system in the car....
although that is a smplistic way of looking at it its fairly close... the amount of Amps that can be drawn through the PWM is dependant upon the PMW itself... if its made to handle 30 amps you'll not want to run any more than about 25 amps max... if its a 50 amp PWM then 40amps max... the bigger they are the more heat output and its safer to give them a little more breathing room ! and don't push them very hard.
....
so if your only going to run 20 amps  a 30amp PWM should do the job and reduce the lad on your electrical system to about 4 or 5 amps less than your original hookup... so drawing 15 amps is better than drawing 20 amps... at least from your altenators view-point....
however unless the PWM has a frequancy adjustment chances are you'll loose a bit in LPM output in the bargin.... Actually its about like powering the cell with 15 amps instead of 20 amps... the diference in output... and I think you can see why <GRIN>
....
PWM's are NOT needed.... to me they are just something else to break...
they do reduce the load but you can do that good by reduceing the electrolyte mix too !
 Reports say PWM's help production a bit ... some say otherwize... its a "Pig in a Poke" at this point in time!( you don't know what you'll get!)
.......
personally I havn't found the NEED for a PWM yet... I'ed rather have a solid hookup to my cell... not something that will smoke if I screw up on the electrolyte mix !
...
a PWM sends its power in pulses to the cell  that much is correct...
the theory is, if that pulse is the same resonant frequancy of the water/electrolyte mix in the cell it may help make more HHO... which seams to be true... but the gain is very small indeed...unfortionately
...so is there really a NEED for the PWM ?  I say NO !
if your worried about the load  you can reduce the electrolyte mix  and lower the load that the chargeing system sees.
but you will put out less HHO in the proccess, but you will with a PWM as well... so what have you gained by useing one in the first place ?
....
if I was trying to resonate the power with the electrolyte then I would need a PWM... or run high voltage as Bob Boyce did and High amps and needed to control it some way... then a PWM is needed ...but for a simple  Hydroxy supplimental system on your car ... Nah.... I don't think ya need one.
....
Bob.......

[Manta]

Bob,

As I understand it,  the strong electrolyte mix is required to give a high current while keeping the plates reasonably far apart.  But this high current may cause problems with thermal runaway once the cell warms up.The PWM allows for the high initial current but progressively reduces the time the current is applied to the cell whilst still maintaining the same hydroxy output that you had when the cell was cool.
In many respects it works like having a cell with variable strength electrolyte or variable spacing.

Or am I missing something ?

Manta

[Bob]

Oh yah ! I forgot to mention that part about the PWM...  THANK YOU Manta !
it gives you the ability to get a 20 amp draw from the cell when its COLD  at startup
and be able to turn down the amps as it warms up ...
  this is actually a very GOOD reason to have a PWM... when I set my cell to 15 amps cold so it would not draw over 20 amps when it was hot I was really hurting the production of HHO
but I have a long drive one way its 50 miles into town...and so setting it for the WARM end of the scale is about all i did...
if I had a PWM it would cure that problem ...and be able to draw 20 amps cold and 20 amps while Hot too
...
Bob.....

[H²+O]

ok guys how am i going to get AMPs (at 12-14V) when i have my generator on my bench? i've heard hooking a charger upto a battery and hooking the battery upto the generator. will that work?

something i don't understand about a PWM, can you set it at say 30A(knowing that the setting is 30A because you tested it already) and the current will rise to that level or does the current jump to that level and stay there, not going over?

what if i build a cell that holds steady at 75A with out a PWM. how will the PWM/cell react when i turn on the pwm(setting it at ?A(75?)).

[Bob]

Ok A PWM (Pulse Width Modulator) can be used in many ways...
 you can set the current load in your Hydroxy cell by the Electrolyte striength so that it cannot go over the Max amps of the PWM.... (like 25 amps set with the electrolyte, for a 30amp PWM.)
...
.... but this does not give you the benifits of having a STRONG electrolyte !
...
another way to do it is to set the Electrolyte at MAXIMUM Striength...or the point of Saturation
of the KOH...  "regardless if how many amps it CAN draw"
then you can adjust the PWM to limit the amps used to a amount below the raiting of the PWM
...if you adjust it to 40 amps and you have a 30 amp PWM you will burn out the PWM in a hartbeat!
...
although Risky the last method is the best, because you have the benifits of the strong electrolyte in the cell.... a strong electrolyte means better continuity between the plates and easier for the cell to produce Hydroxy gas because of that. it also means LESS HEAT... and this is the MAIN reason to use this method. lower resistance in the electrolyte will generate less heat as the electrons travel from plate to plate... heating the water in doing so.
... But you can FRY the PWM very easy doing this ! all it takes is turning the knob the wrong way one time and you smoke the PWM because you set the load of the cell at say 50amps by the electrolyte and the PWM can only handle 30 amps.  so you MUST BE CAREFULL !
...
another way of reaping the benefits of the Strong Electrolyte concentration is by the use of a "Current Limiter"... although I am still quite fuzzy on how to make one up, its supposed to be fairly easy to put a resistance coil in line (SERIES Hookup) with the cell and it cannot draw any more amps than the Current Limiter does.
and it has no moving parts, and should last for years if built correctly.
...
the only problem is making up a coil that draws exactly the amperage that you want... once you have that, you can put it in series with your cell and then the cell cannot draw any more AMPS than the coil does. (wire wound resistors or large carbon resistors can be used  and the Amps can be found using Ohms law.)

....
Bob.......

[Bob]

H2+O....
I used a GOOD car battery on the test bench for a few months , hooked to a 10amp charger
which gave me about 30 min of 20 amp draw... then I needed to quit so it could recharge the battery.
... a Large Battery charger that puts out 30amps is hard to find and expensive and some of them Lie when they say they can put out that much continuously...<GRIN>
...
I needed More amps to test with so I tried useing my AC/DC ARC WELDER ! although it put out 110 volts and 295amps DC I could adjust the amp load on the welder ...
this worked great for lower settings but when I got to 75amps  I blew the curcuitbreaker on the power pole and everything went black ! ... that ended that experiment even if I got over 5LPM !
...HAHAHAHAHAHAH
....
but an arc welder IS NOT like having it in your car...by any means and it is best to simulate the car !
...
Bob...

[Bob]

Also... something you should be aware of....
when you hook a 10 amp charger or 6 amp charger...what ever it is and hook it to a battery and then hook a large load to the battery like 20amps ...your charger will see that 20 amp load and more than likely shut down thermally in a few seconds ...( because it over heats) this is hard on chargers ! and they won't last long putting it through that kind of Punishment !
... However your battery can see the 20 amp load and just discharge slowly...
so I sujest that you put the battery on the charger but take the charger OFF before you do your cell test....soon as your done with the test put the charger back on it... as it will be low and need to be re-charged.
...
this is far from Optimum I realise but it may save you from having to replace the battery charger as I thought I was going to have to do with my Dads 35 amp battery charger...
... at 20amps draw it would over heat and shut down with a Audable CLACK!...and thats all she wrote till it reset itself in about 15 min....
with My old 10 amp charger it would Pop off as I was doing the test and pop back on durring the test and keep doing that till I took the load off !but the amps really suffered and gave me inacurate readings because of it.... thinking I was getting 20amps and only getting 12 to 15 max changes the output expected very much !
...
I got wise and Put a good amp meter between the battery and the cell and discovered that my power supply was weaker than I thought !... come to find out my battery was not very good and more of the load was shifted to the charger that couldn't handle it... so I was kind'a STUCK
.... and still am,... till I can get a "Big SHOP Battery charger" one capable of 100amps !or more
...
this is one of the reasons I havn't played much with Hydroxy cells as the only way I have to test it with proper voltage and amps is ON the TRUCK !
....
but I am Hoping come Turkey day I can get a Large Shop Charger... Lord knows we need one on the ranch here !<GRIN>
...
another method is an electric motor ( fairly large) turning a automotive altenator...
the standard altenator usually puts out about 65amps... and if its turned by a 2hp electric motor it should be able to keep up with the demands of a 20amp draw...
.... it would make a nice project to build in the shop this winter to test cells on !  although you still need a battery along with the Altenator, its able to give you an Automobile "SIMULATION".....as far as the power output goes.
...
its a thought !
Bob.......

[H²+O]

Awesome Thanks Bob!

I was thinking about it when i first posted it and it was really getting to me  . But problem solved! Or at least it's solved when I get the stuff for it!!!

I bought a cadlack alternator on Boise.craigslist.com (I put that in there just in case someone doesn't know about craigslist.com ) it cost $25 and it was a brand new 140AMP! (they bought it a year ago and never used). I was going to (still am in fact) rigg it up to my 3.5hp b&s (once i get the magneto whipped) and see how much hho it take to power the sucker ! but i think I'll just use it with regular gasOline then convert later once i've done my tests.

I might have a arc welder around here somewhere.... I'll take a look, How many volts do an arc welder put out???

steve

[Bob]

Ok first off that was a great buy on a 140 amp altenator !...and thanks for the link !
second off, that 3.5hp B&S will never turn that altenator...WITH A LOAD... it will turn it fine
albeit hard as hell to start with no load...but soon as you hook up a battery to charge on that thing it will load the motor down so much it will lug down and die...
been there done that with a smaller Altenator...when I was younger... it takes about 10hp to turn a large altenator.... but it might charge small things...give it a try sense you have the stuff there !... maybe you can run higher RPM and usea larger pully on the altenator...I never tried that.
....
an arc welder is usually an AC Arc welder... and puts out about 110volts AC but a huge amount of amps... (295~300amps)  at least my 3 do.... but I admit I never put the VTOM on the AC arc welders ....just the AC/DC welder and I did test both AC and DC and the voltage was the same.
...strangely enough sense it plugs into 220vac !  but it definately welds good ! HA!
...
at one time I had a very small Arc welder , a cheapy that I got before I knew anything about welders and wound up giving it to my friend when I moved I think it had 75amps welding ability and pluged into 110vac/30 amp plug in... it coat about $99.00 some 30 years ago I think....
...
the thing about welders is they are not designed to POWER something continiously...
this is why I mentioned my welder throwing the curcuit breaker at the power pole at only 75amp setting ,when I was running a test on my Hydroxy cell.... and the only time I ever threw the breaker while welding before was with the Amps turned all the way up and was using the welder to cut/blast appart a piece of 1/2" steel...and that was at 295amps setting...
...
info...FWIW.
....
Bob.......

[sixpack127]

For those of us in cold climates - the strong electrolyte will keep the fluid from freezing - not sure what the temperature range is - I know I have seen it somewhere though (living in Michigan - we get the "best" and "worst" of both worlds - freezing temps and obscene heat)

[Bob]

I have seen KOH Electrolyte in "Slush Form"  it was so cold...
however that may be as HARD as it gets... just SLUSH !  if thats the case then we don't need to worry about it freezing solid and splitting the tank !
...
Bob...

[sixpack127]

Thanks Bob

Another question - has anyone tried to route a small tube from the coolant system through the reservoir tank to heat up the electrolyte?

[Manta]

I should image that would not help.  You need the electrolyte to stay liquid during the periods when the engine is not running;  at night , for instance.  It follows that the engine will be cold and so would your coolant heating system.

Also when the engine does start up,  you would be faced with the opposite problem;  the electrolyte getting too hot.

Dave
(Manta)