1 Large cell vs. 2 Small cells

Hi everyone,
I'm extremely new to this forum and HHO in general. I’m interested in building a dry cell.

Would a 12”x12” with 11”x11” exposed plate surface be a better than two cell’s that are 6”x6” with 5”x5” surface exposed?

The reason I ask is that I read that there is a fluid temperature at which you have optimal hydrogen output.

Also is a large cell inefficient at low amperage?

I have a 95' Honda Civic DX 1.5L OBDI which I would like to install the cell into and I would like to run the cell at no more than 20A.

Any help and suggestions are appreciated thanks.:D

For your engine, you would probably need not more than 0.3 LPM @ let's say 4-6 Amps.

That is without leaning the fuel/air ratio.

If you wish to lean the ratio, you'll have to deliver more than 0.3 LPM. Maybe double. Or even 1 LPM.

A 1 stack reactor that can produce 1 LPM @ 15 Amps would require plates of 6" x 8".

If you sandblast the plates, 5" x 7" or 6" x 6" can be ok.

However, if you want to build a reactor with big plates, the height of the plates should be 6" maximum. You should only increase it by increasing the width. That is for efficiency reasons. You don't want the gas to travel too much to get out of the reactor.

Other than that, I'm not sure how plate surface affects the efficiency. Maybe some more experienced people can tell you that.

However, the number of plates and number of stacks does affect efficiency.

An efficient 1 stack reactor must have 7 or 8 plates. that means 5 or 6 neutrals + 2 electrodes. If you have less than 5 neutrals or more than 6, you start losing efficiency.

If you add more than 1 stack of neutrals to a reactor, efficiency goes down. A 2 stack reactor will create more gas than a 1 stack reactor, but if Amperage in relation to active surface are taken into consideration, the less stacks of neutrals means better efficiency.


I'll say this to resume everything above and answer your question:

- very important is the number of neutrals in a stack, which should be 5 or 6.

- for 1 stack reactor, I'm not sure if plate surface plays an important role other than the height, which should not exceed 6", which is a rule of thumb.

- the more stacks of neutrals you have, the more you lose efficiency

- 1 reactor made of 2 stacks is less efficient than 2 reactors with 1 stack each.



I hope it makes sense.

whear thanks for the reply it does make sense.

I will run a single stack being that it is more efficient with 7 plate stack 5 neutrals 6"x12".

The reason for the larger design is that I have a 72 Dodge Dart 318ci with a Edelbrock 600 carb and would like to test the cell on that vehicle also.

If I don’t exceed the 0.5A/square inch surface area I shouldn’t have problems with water vapor or am I incorrect.

What end plate material is recommended?

Yes, you're correct about the 0.5 Amps / square inch.

With 6" x 12" plates, you don't actually have 6 x 12 = 72 square " active area. That's because you need to subtract the gasket area.

Roughly, you won't be able to exceed 27-28 Amps. Maybe 30 if you sandblast the plates.

A good material for end plates is HDPE or EDPM. At least 1/2" in thickness. Preferable 3/4".

Thanks again whear I will look into that material.

I was thinking about running 20ga. 316l plates does that sound good or is there a better thickness to run.

The HDPE is for the end plate and the EDPM is for the gasket?

I already ordered 12"x12"x1/2" Acrylic for the end plates and 12"x12"x1/16" Buna for my gaskets from Grainger will that work?

I can order the other materials if they won't.

I did a quick research on Buna material, and it doesn't work with strong bases. You should get Neoprene, EPDM or HDPE for gaskets.

Also, Acrylic is not your best choice as end plates since it's not very resistant to heat.

For end plates, HDPE or EPDM.

For gaskets, neoprene, HDPE or EPDM.


20ga for the SS plates is ok. However, if you get thicker plates, such as 16 or 18 ga, it's less probable that you will warp the plates when you sandblast them.

In any case, it's good to have at least 1 extra plate for testing.

whear thanks again it looks like I'll be spending a little more money.

As far as the 316L plates I will order the 16ga. as recommended (McMaster-Carr #88885K24).

End Plates Sheet, HDPE, White, 3/4 In Th, 12 x 24 In (Grainger #3HML6).

Gasket Material Rubber, EPDM, 1/16 In Thick, 12 x 36 In (Grainger #1MYD2).

Any other suggestions are much appreciated.

koya1893 that sounds great what MPG are you getting out of her?

Fuel Injected or carb setup?

I hope I'll be able to drive the Dart to work soon, it was getting around 12MGP before I put it in the back yard for upgrades (rear end and electrical work).

If you're planning on producing more than 1 LPM of HHO ( which you can with your setup ), you'd want to use slightly thicker gaskets. 3/32" or 1/8".

Say 3/32" for ~1.5 LPM and 1/8" for 2 LPM+

This is also a rule of thumb that I learned from Carter ( myoldyourgold ) :D

Thanks whear,

If I purchase the 1/8" will that cover all my bases or will at lower LPM production having the plates closer is a better design?

I can order a few different thicknesses for tuning if this is the case.

Is there a flow hole placement design (liquid and gas passages) that you can recommend?

Thanks again for all your advice.