low output?

[nst6563]

I'm relatively new to the dry cell, messed around with a wet cell a couple years ago and priorities changed. Anyway, just for experiments sake, I've got 13 ss plates 4"x6". Small hole in the bottom, large hole in the top. Plate configuration is -NNNNN+NNNNN-. Currently using (roughly) 1/16" rubber gaskets tightened down thinner. Electrolyte is roughly 10% KOH.

Right now I don't have a resevoir setup to circulate electrolyte - might be part of the problem. When the cell gets low I simply stop and re-fill. The resevoir might come into play this weekend if I have time. Run over the period of a couple hours the cell gets VERY warm/hot - circulating the electrolyte would help this as well from what I understand.

Anyway, with the above specs running at 12v 6A I barely get a water bottle (standard 500ml) filled in a minute. I have a small hose on the output right now as well so that is most likely restricting things a bit. Hopefully I can get larger hose this weekend as well as the fittings.


Am I expecting too much or am I missing something?

Thanks in advance for helping a noob ;)

[koya1893]

nst,
Welcome to the forum and welcome back the "madness". I am running similar configuration on the Infiti and half that on my Harley. Are your holes staggared? did you media blast (sand blasted) the plates. When you say very hot. Did you use a IR thermometer or just to the touch? I can run my cell for 4 hours straight, it will get to 110 degree. Also, when you ger a reservoir, make sure the top of your cell is just at the bottom of your reservoir so it will circulate and let gravity do it's thing to do so.

I've been trying something new, well I don't know if it's new. I saw a cell built by Larry using the same gasket pattern to prevent some of the voltage leakage. The key to some of the great production on my cell isthe 5N and 7 plates for single stack and 5N 13 plates for two stack.

When you say 10%, how did you come up with that? Just curious if it is the same calculation as everyone in here. I use NaOH for easy access and use 2 lb. per gl.

By the way, do a search on WELD ON 16 in the forum.

[D.O.G]

I'm relatively new to the dry cell, messed around with a wet cell a couple years ago and priorities changed. Anyway, just for experiments sake, I've got 13 ss plates 4"x6". Small hole in the bottom, large hole in the top. Plate configuration is -NNNNN+NNNNN-. Currently using (roughly) 1/16" rubber gaskets tightened down thinner. Electrolyte is roughly 10% KOH.

Right now I don't have a resevoir setup to circulate electrolyte - might be part of the problem. When the cell gets low I simply stop and re-fill. The resevoir might come into play this weekend if I have time. Run over the period of a couple hours the cell gets VERY warm/hot - circulating the electrolyte would help this as well from what I understand.

Anyway, with the above specs running at 12v 6A I barely get a water bottle (standard 500ml) filled in a minute. I have a small hose on the output right now as well so that is most likely restricting things a bit. Hopefully I can get larger hose this weekend as well as the fittings.


Am I expecting too much or am I missing something?

Thanks in advance for helping a noob ;)

G'day.
As you said, fitting a reservoir to get electrolyte circulation will probably go a long way to fixing your heat issues.
If you're making 0.5 litres a minute from 6A, you're doing fine. The problem is, if you're running that hot, your measurements are going to be less once the heat is reduced because hot gas occupies a greater volume than cold gas.
Anyway, keep going with it you seem to be on the right track.
Pete.;)

[nst6563]

Thanks guys. I did notice that after running the cell 'hot' it does begin to fill the bubbler up more due to the steam generated (I can also see the steam forming on the insides to the clear tubing).

I'll really work toward that resevoir this weekend.

As for the electrolyte mix....I simply used what I had on hand :D
Tight on cash right now so until I can get some money freed up I had to use what was on hand.

Plate prep. I've read a lot about that and have seen mixed opinions between just sandpaper and media blasting. At first I did try sandpaper...but then I tried media blasting. Not sure if there's a difference in output other than with the media blasted plates the bubbles seem to be smaller.


What are you guys using for gaskets? Also end-plates...I see some that use 1/2" acrylic, and others using something like Koyo's (solid non see through).

:edit for missed questions:
The ports in the plates are SOMEWHAT lined up. With the wet cell I only had 6 plates. This time around I got 5 more and re-used the old plates (after the sanding, media blast, and a good cleaning). I drilled each stack seperately with a drill press. However, in a typical noobtard mistake, I didn't use a plate from the first stack to line up the hole on the 2nd stack. So they're MOSTLY in line with each other, however some are slightly offset. I checked out the weld-on 16 and noticed mention of it not being recommended for blasted plates. It should still stick around the inside edge of the ports where it needs to be right?

When I've got all the kinks worked out this is going into a '04 Maxima SE - not much room under the hood so I've got quite a bit of work to do ahead of me.

[nst6563]

changed my setup a bit...
I was using -NNNNN+NNNNN-
Now I'm using -NNNNNN+NNNNNN-NNNNNN+, PVC gaskets, a reservoir to circulate the electrolyte, and larger diameter tubing (3/8" ID) - getting MUCH better results at less amps than before (only running 4 amps now as opposed to 7-8amps before)

After media blasting all the plates again, cleaning, and now they're conditioning. I added just a 1/4tsp of NaOH to 2L of water and am getting a nice flow through the tubing and it's not even warm to the touch after an hour.

only problem....I split the front plate while tightening things down. Any recommendations on front/back material? I've seen HDPE thrown around - but then I've also seen the idea thrown around of a cheap alternative is a 3/8" or 1/2" cutting board - thoughts?
thanks!

[BioFarmer93]

Cutting board is HDPE. At 1/2" thick it will warp if you are not careful about bolt locations/quantity. A good trick is to make a set of 1/4" thick by 3/4" to 1.0" wide steel plate perimeter bands with the end plate hole locations drilled in them to stabilize thin plastic end plates.

[nst6563]

Thanks. I didn't realize cutting board was hpde...good to know ;)
Is Acrylic stronger than HDPE? I found a place that sells a 1/2" x 12" x 12" Acrylic sheet/plate for $10.

I've been running my cell for conditioning the plates and so far so good. With the reservoir setup using 3/8" ID tubing for in and out I get nice production for only 4A. I let it run all day yesterday and the entire cell was cool to the touch and only a bit above room temp.

This morning I changed out the electrolyte solution and increased the NaOH content to raise it to 7A. I get a LOT of tiny bubbles...very tiny and quite a few larger ones. The tiny ones seem to cloud the water and float to the surface more slowly - are these the hydrogen bubbles while the larger ones are both hydrogen and oxygen? If there are more tiny bubbles than large ones...do I need to increase plate spacing?

I plan on doing a lpm test later today after letting it run on 7A for a while.

[BioFarmer93]

The tiny bubbles and the big ones are both.. They don't divide up like that. The big bubbles are just a bunch of tiny ones that decided to form a gang..:D
You didn't mention your plate spacing in the post so I can't say if it's too close or not.

[nst6563]

sorry, the spacing is currently slightly less than 1/16". Gaskets are a poly mesh with pvc coating - supposedly good to 170 f.

I was thinking of trying the cork/rubber variety that can be found in automotive stores.

I've got the cell tightened down quite a bit and was looking at other options for gaskets that may not compress as much.