Cell help

[Theexp]

Hey,
I'm new to the forum but I have been lurking around a little bit picking up some info.
I have recently built a 25 plate series cell for TSA (Technology Students association). It works great. I built an acrylic container, that was 6x3x3. The acrylic was a quarter inch thick. So I glued it all together and made a little compartment for a bubbler. I then cut (with a grinder) 25, .036"x3"x2.5" 316 stainless steel plates and epoxied 4, 3/8" in daimeter 1/8" thick acrylic circles on each plate. I glued 2 little spacer pieces together then put 4 on both sides on the end. I attached a little piece of 316 stainless steel (like a little wire) i had cut off to act as a electrodes to both endplates. I glued a lid on, and tapped 3 holes in the top (one for filling, one with a hosebarb to the bubbler, and one more for the bubbler output.) I then drilled and tapped a 1/4" hosebarb (with an extension tube epoxied in to push bubbles out further) and the cell was done. I sealed everything up. I then went to radio shack and bought a full wave bridge rectifier (25a, 50 volts) and some 10 gauge wire. I cut the end off of an extension cord and soldered the 2 ac outputs to the 2 ac inputs and soldered some 10 gauge wire to the 2 outputs.
The voltage on the output is way to high, so that is my first question, it comes out as 110 volts, how can i lower it before it comes in or on the way out. (I tried a modified europeon transformer, but it was either broken or I shorted it, becuase it was only giving me 5 volts on the ac out side of it before the bridge rectifier).

How can I lower the voltage down to 50 volts from 110 DC @25a, or 120 AC @15a?

I then filled it completly with distilled water and NaOH (lab grade) (about 30 pellets for like 10 fluid oz). I did this outside and I got my dad to watch it while i plugged it in, and instantly it sprayed out about half the bubbler and about three fourths of the cell resivour. I thought about putting a filter the whole to pop the bubbles, but i was unsure, so that is my second question.

How can I prevent the cell from over bubbling?

I removed about half of the electolyte and distilled water solution so it wouldn't bubble over. I ran it for a little bit and found it was overheating to the point were watervapor would come from the bubbler. I know lowering the voltage will keep the heat down.

What should the concentration of NaOH be to distilled water?
How Can I help prevent over heating?

And finnally my water is getting an orange brown color, with dark brownish orange chunks that float around. I don't think that it is the plates corroding but it could be. I was thinking it could be the epoxy.
I was wondering what it (the orange brown stuff) was and how I could prevent it from happening? Sometimes the cell will smell when i run it.

I just got a great idea to mill the spot accepting the lid flat with my drillpress (old shopsmith works GREAT) and crosssliding vice. next time. I'm gonna mill the sides flush.

Thanks alot.

Heres a pic of the plates i cut (that took forever with a 4 and a half inch grinder)
http://i2.tinypic.com/vcqujn.jpg

The Bridge Rectifier (still needs a switch so i don't have to unplug it to stop it) The second one is the project box its housed in. It has heatsink grease on the bottom to transfer heat better.

http://i2.tinypic.com/vcqurt.jpg
http://i2.tinypic.com/vcqxaq.jpg

This is the orangy brown liquid and plates.

http://i2.tinypic.com/vcqxlg.jpg

These are 2 pics of the entire Cell
http://i2.tinypic.com/vcrm1x.jpg
http://i2.tinypic.com/vcrm1i.jpg

[hkyle]

Nice cell....
To try and answer your questions.....

(I have recently built a 25 plate series cell)
instead of lowering the voltage I would add 35 more cells make a 60 cell design. You only need around 1.24 to 2 volts per cell for electrolysis. You would increase you output this way as well. more cells more hydroxy.

(How can I prevent the cell from over bubbling?)
By adding more cells you will lower the voltage per cell. You may also have too much NaOH in your water.

(What should the concentration of NaOH be to distilled water?)
For my cell I add about 1 table spoons of Lye (NaOh) / Liter of water. This seems to be the best mixture for my cell. For my cell I started at 4 table spoons of NaOH per Liter ran my cell tested how much Hydroxy was produce. After the test I kept adding water to the electrolyte until the production dropped off. There is such a thing as too much......

(And finnally my water is getting an orange brown color)
Too put it simple you are cooking your electrolyte from the high voltage per cell. Keep adding cells to your design and you will notice that your electrolyte wil stay cleaner. You have 25 cells and you are adding 115 volts to 120 volts at 15 amps that means you have 4.6 volts per cell at 15 amps. try and get around 1.5 to 2 volts per cell. If you did your cell should not produce a whole bunch of waste heat. You would also keep the water vapor down in the Hydroxy gas mixture.

By looking at your design It looks like you might also have some current leakage around the ss plates. You want to totally seperate each cell from the next. Check the current level at each cell, for example if you had 20 volts and 10 cells your voltage should drop aprox 2 volts per cell until you get to the other end. check with a voltage meter.

ummmm I think so anyway!!! Hope I helped.

[dcyoung9]

hkyle,
Looks like it would be hard for him to add more cells without starting over with his box. I'm very new at all this (been plowing through these posts for several days) so don't know much, BUT couldn't he add light bulbs in series and cut down the current and voltage to an acceptable level to get the desired voltage and current for his existing cell? He may have to put several bulbs paralell with eachother but in series with the source, 110V, and the cell. It would be like using one of those bathroom multi-light strips in series from 110V to the cell and just adding, screwing another bulb into the fixture, to up the V and Current to the cell until he was at his desired max. The size of the bulb (wattage) could also be varied to fine tune the output. What do you think??? Don

[BEMET]

Theexp
Quick fix. Not for efficient electrolysis but to get it to stop overheating/bubbling over using your present apparatus.

Dilute your electrolyte a lot.

Start with a few drops of your present electrolyte to a quart/litre of distilled water.

I also have gotten rust colored stuff floating around in the electrolyte using KOH. I filtered the rust out using a paper towel. Be careful. Any electrolyte touching the skin will cause burns but lye can be neutralized with vinegar.

[hkyle]

dcyoung9
He could also go down ad get a rheostat. A lot easier that adding and taking away light bulbs.

[hkyle]

I was just making a point that his cell would be or could be allot more efficient if he added cells. I was going to mention on my first post that it would be difficult for him to add cells but we all know that there is allot of trial and error when working with this stuff.

When making a cell you must keep in mind the efficiency of the cell why waste voltage if you don't have too.

The quickest solution would be to add a rheostat before the bridge. Then you can easily adjust the voltage and amperage accordingly.

[Theexp]

Hey thanks alot for the replies, the problem with trying to seal each cell off from one another is that I cut each plate with an angle grinder so they all aren't the same size due to low money. I might make a new cell during summer (once i start working again) so it'd be a 60 cell design.
So pretty much my main problem is too much NaOH and too high voltage.

SO i just need to drain it all and refill it with a diluted concentration and get a rheostat?

[Steve-tee]

Perhaps you could use a lamp dimmer in place of the rheostat.
This would let you perform the dimming function without generating large dollops of heat in a variable resistor.

Ok, the dimmer will impart full mains voltage to the cell, but it will also limit the duration of those pulses, so the average figure will be correct.

The dimmer would be placed before the rectifier, so as the rectifier and the cell take the place of the lamp that the dimmer is designed to drive.

I hope this helps.


Best wishes,
Steve-tee.

[jeffm]

Are you sure that your cell is really a series cell? From looking at the picture, the water has these peaks on boths sides of the plates, making it look like the water is not at all separated between plates. If this is the case, then what you basically have is a single cell electrolyzer, running at 110 volts... This would explain the water exploding, and turning to rust--you're burning up your electrolyte, and probably damaging the plates.

Try running your cell off of a 12v car battery.. If you did have a 24 series cell electrolyzer, you should the tiniest bit of output (if any) at 12 volts. If you have decent output, then, I'd be pretty sure that your cell is not series at all, just a single cell with a lot of surface area.

Try getting some of that flexible pvc that is used in bob's series cell, and line the sides and bottom of your enclosure with it, it would probably do a decent job of sealing off your plates, unless the cuts are too far from straight.

[ElectroGasMan]

Hi all

When I first started reading about H2O2 gas makers I started with tubes for plates. Then I read of Bob's boat races and later went to flat plates for compactness.

With pure water and tubes I use 4 Volts per cell for a total of 3 for a car booster. I do not have any GAS data yet but will measure it soon.

I also used a motor control and noticed a great difference.

Here are some testing chambers with pop tops and manifolds.

http://www.flickr.com/photos/75555779@N00/

Thanks this is my first post.[/img]