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alpha-dog
01-29-2009, 04:05 PM
I do have a MX067 pwm modified to use a P-channel mosfet that is working.
Basically the P-channel fet switches the positive voltage from the battery. I've only found one mosfet that is a good substitute for the N-channel fet we have been using.
The problem was finding a P-channel fet with the same Vgs(th) gate threshold signal as the N-channel fets use that we find in our pwm's. Part # STP80PF55 has the same gate threshold signal requirements and can be used in our pwm's. The gate ( pin 1 ) and drain ( pin 2) connect the same way as the N-channel fets. The source ( pin 3 ) of the P-channel will connect to the positive battery post and of course ther N-channel source ( pin 3 ) connects to the negative post ( ground ).
How I modified the MX067 ( MX068 uses same schematic ) follows:
1) I cut the ground run from the driver portion of the pwm to where the ground spade terminal is.
2) I cut the run between L+ and positive spade terminals.
3) I attaached a wire from L+ spade to the ground run returning to the driver circuit.
4) I removed the flyback diode - D1.
5) I removed the N-channel mosfets and installed in thier place a P-channel mosfet.
How I connected the pwm to the HHO electrolyser:
1) I connected a positive voltage from the ignition circuit to the + spade terminal on the pwm.
2) I connected ground to the L+ spade terminal on the pwm.
3) L- still goes to the HHO electrolyser.
4) The ground spade connector now connects to the positive post of the battery ( or the HHO relay )

I do not know if this will work better than N-chanel pwm's. I believe it will work better. When I was testing it my resovior and electrolyser were leaking. I'm in the process of making repaires. One thing that I did notice is sthat the higher PRF I dialed in the current would drop. This is with a 60% duty cycle.
I should know more this weekend.

tomisnt
01-29-2009, 09:22 PM
Thanks for your contribution alpha. I will play with one soon.

alpha-dog
01-31-2009, 01:02 PM
I ran a few test today comparing two MX067 pwm's. One has N-channel mosfets and the other has P-channel mosfets. My little test electrolyser only produces .5Lpm at 4.7 amps with the N-channel. Although the gains were small the P-channel pwm out preformed the N-channel pwm by maybe as much as 10% with the same current draw at a PRF of 100 hz. This is after a few hours of running the electrolyser.
Russ

Painless
01-31-2009, 01:27 PM
So, you're saying that the p MOSFET PWM produced more HHO for the same watt power?

I've been thinking about the stored power within a cell when its not receiving power from the PWM. Imagine a PWM that controls both the p and n sides with synchronised MOSFET's, yet, during the off cycle it connects positive to negative allowing to cell to power itself.

alpha-dog
01-31-2009, 04:24 PM
So, you're saying that the p MOSFET PWM produced more HHO for the same watt power?

I've been thinking about the stored power within a cell when its not receiving power from the PWM. Imagine a PWM that controls both the p and n sides with synchronised MOSFET's, yet, during the off cycle it connects positive to negative allowing to cell to power itself.

Yes!! I used the same electrolyser, KOH solution, ect, ect. Also, after the test were done with the standard pwm I immediately tested the P-channel pwm. So the water temperature was the same. I made a mark on my HHO flow meter at water line with the standard pwm and retested 3 times verifying the mark. The P-channel consistently moved the 1.5 liter bottle up 5/16 inch higher at the same amperage ( 4.7 amps ) and PRF (100hz ).
Also, that is what I have been saying about SDC current. Using the mosfets that I've found STP80NF55 and STP80PF55 working at the same Vgs(th) gate threshold signal. When one conducts the other is off. You could use an inverter to produce a gate\not signal. With a gate and gate\not signal and these mosfets provides the switching needed for SDC current in an electro-magnetic cell.
Russ

alpha-dog
02-06-2009, 11:20 AM
I got my flow meter in yesterday and was able to do some better test on a modified P-channel pwm. ( I'll be doing the current limit mod next ).

At:
PRF = 4.761Khz
Duty Cycle = 80%
Amps = 8.2 amps
Lpm = 500 ml
volt = 10.8
MMW = 5.65


One thing very interesting I discovered is that the higher the PRF the less current used. MMW dropped a little bit ( 50 ml ) from DC current, but Pulsed dc current dropped from 13 amps to 8.2 amps. Using this low of a voltage should give bad results but the pulsed dc is very efficient.

Gforce
02-07-2009, 01:51 AM
Keep in mind if you are measuring the voltage with a meter you will get the average. The voltage is actually getting switched on and off with the PWM.
When it is on the voltage is higher. If you were to look at it with an Oscilloscope you would see and measure the peak voltage.

13.8V......___ ..___....___
Ave -----|--|--|--|--|--|------
________|...|__|...|_|...|______

The thing I am pondering is it more efficient to use a variable voltage rather than a PWM. This can be done by adding an inductor and capacitance.

alpha-dog
02-07-2009, 12:31 PM
Keep in mind if you are measuring the voltage with a meter you will get the average. The voltage is actually getting switched on and off with the PWM.
When it is on the voltage is higher. If you were to look at it with an Oscilloscope you would see and measure the peak voltage.

13.8V......___ ..___....___
Ave -----|--|--|--|--|--|------
________|...|__|...|_|...|______

The thing I am pondering is it more efficient to use a variable voltage rather than a PWM. This can be done by adding an inductor and capacitance.

I use an o'scope. Also, I measure DC before the pwm. That's why I can measure PRF and duty cycle. I'm thinking that pulsed dc allows the stored energy to be used. That's just a theory of course, but there is a marked increase at the same current draw between the N-channel ( common pwm ) pwm and the one I have modified for P-channel mosfets. I'm going to make current limiting work next, then it'll be ready for my truck.

Q-Hack!
02-07-2009, 01:15 PM
Keep in mind if you are measuring the voltage with a meter you will get the average. The voltage is actually getting switched on and off with the PWM.
When it is on the voltage is higher. If you were to look at it with an Oscilloscope you would see and measure the peak voltage.

13.8V......___ ..___....___
Ave -----|--|--|--|--|--|------
________|...|__|...|_|...|______

The thing I am pondering is it more efficient to use a variable voltage rather than a PWM. This can be done by adding an inductor and capacitance.

Isn't ASCII art a PIA...


13.8V....___....___....___
Ave ----|---|--|---|--|---|------
________|...|__|...|__|...|______


It works a lot better if you set the font to a standard width like "Courier New". Those variable width fonts like "Times New Roman" will be different for people on Mac's and Linux boxes. :)

alpha-dog
02-16-2009, 08:07 PM
Thought I'd let you know that the current control comparator works fine. Look for a schematic.

alpha-dog
02-20-2009, 12:23 PM
I did some MMW test today using one of the electrolsyers in my truck. I also was testing the current monitor/control circuit.

volts = 14vdc
amps = 40a
pwm = 2 P-channel mosfets
freq = 5khz
duty = unsure ( less than 70 % )
current control = max
stacks = 2
total plates = 13
MMW = 5.86
Lpm = 3.3 Lpm


volts = 14vdc
amps = 26 amps
pwm = same
freq = 5khz
duty = less than 70%
current control = adjusted to see change
stack = 2
total plates = 13
MMW = 6.57
Lpm = 2.35Lpm

Looks like I'm going to get close to my goal of 5Lpm. The current control doesn't work good enough for me yet. It is dry gas, the bubbler is about 2 feet higher than my reservoir with condensing coils. I measured with a homemade flow meter for accuracy and also a commercial flow meter. Going back to the drawing board now to make it better.
Russ

joel.benavidez
03-03-2009, 05:24 PM
I'm not a hobbyist. My electrical knowledge is far too limited at this point in my life. After Nursing School, i may go to a technical school to open the doors on this.

But I am waiting on a Vada Energy Max 1400 Kit + a single vada EFIE which should arrive this week or the next. (will be doing an "unboxing" on youtube[dot]com/saintskyler)

Vada's PWM manufacturer has stopped producing units so I will be buying a MX067 PWM on ebay. I'm just hoping that the two units together will not drain too much from the battery and alternator on my stock 2006 Honda Civic LX i4 cyl. I've already gotten positive feedback from from Vada on the proposed setup, still waiting on feedback from the ebay seller, "arizonavideo".

What do you guys think?

I plan to merge the units in a clear acrylic casing with 2 PC fans (1 in, 1 out), some LED lighting, and total symmetry in mind. Once completed, I'll probably mount the case in the center of the back seat, facing forward "flux capacitor style".

Anyway, from hearing you guys talk about the technical specifications (which are greek mumblings to me) I thought you guys should be called "Water Hackers". It just sounds neat to me: To think that there is so much that the mainstream scientific community has ignored in terms of HOD fuel systems is mind boggling to me. I can't believe that we have not yet discovered the optimum frequency, spacing, amperage, voltage, chemical ratio, and combination of these per system.

Whatever it is that is optimal, wherever you HHO holy grail is, I hope you all find it, and it remains open source.

Peace.

alpha-dog
03-03-2009, 06:07 PM
I'm not a hobbyist. My electrical knowledge is far too limited at this point in my life. After Nursing School, i may go to a technical school to open the doors on this.

But I am waiting on a Vada Energy Max 1400 Kit + a single vada EFIE which should arrive this week or the next. (will be doing an "unboxing" on youtube[dot]com/saintskyler)

Vada's PWM manufacturer has stopped producing units so I will be buying a MX067 PWM on ebay. I'm just hoping that the two units together will not drain too much from the battery and alternator on my stock 2006 Honda Civic LX i4 cyl. I've already gotten positive feedback from from Vada on the proposed setup, still waiting on feedback from the ebay seller, "arizonavideo".

What do you guys think?

I plan to merge the units in a clear acrylic casing with 2 PC fans (1 in, 1 out), some LED lighting, and total symmetry in mind. Once completed, I'll probably mount the case in the center of the back seat, facing forward "flux capacitor style".

Anyway, from hearing you guys talk about the technical specifications (which are greek mumblings to me) I thought you guys should be called "Water Hackers". It just sounds neat to me: To think that there is so much that the mainstream scientific community has ignored in terms of HOD fuel systems is mind boggling to me. I can't believe that we have not yet discovered the optimum frequency, spacing, amperage, voltage, chemical ratio, and combination of these per system.

Whatever it is that is optimal, wherever you HHO holy grail is, I hope you all find it, and it remains open source.

Peace.

Were you going to try my modification. Its a simple one. If you are not in that big of a hurry I and my friend ( an electronics engineer ) are going to make about ten of these poeple can buy. P-channel mosfets, current control, three or four units makes it versatile. Driver unit, current monitor unit and mosfet unit ( 2 fets in a unit, more than one mosfet unit can be used, N-channel or P-channel mosfets your choice). Easy to change it from 30 amps to 60 amps or even 90 amps.
We are working out all the details now.

alpha-dog
03-15-2009, 03:58 PM
This is the basic pwm driver I'm building


1189

alpha-dog
03-29-2009, 12:50 PM
This is a picture of a P-channel mosfet switch assembly. It contains 2 P-channel mosfets rated at 80-amps and 300 watts each.

1198

Here I've attached them directly on the electrolysers. This will keep heavy current bearing wires to a minimum length.

1199


My twin electrolysers are currently producing 1liter of HHO in 12 sec.