Help for our newbies

[weggl]

[weggl]

[Etownlax]

[weggl]

There are confusing reports out there as to the maximum concentration of sodium hydroxide. I believe it is 26% is this correct or is it 28% as I have heard?
Would appreciate info on the correct level.
Warren

[MarkinAustralia]

Dear Warren,
Bob has some accurate figures on this I believe its between 25% and 28%.
It also depends on your cell, plate area and design.
I tested several types of cells this year with different concentrations.
Fo example one cell I tested between 1% and 20% concentration. It was a sealed cell with small holes in the plates so it was self leveling (not a pure bob one)
With the lower concentrations it was slow to start but after a few hours it heat up and get more efficient. With the higher concentrations it would produce lots of gas instantly...slowly heat up resulting in more amps being drawn and over cooking the cell. To control this we used a pwm device to limit maximum power.
The above applies to straight DC brute forse only. Its my belief that using the ideas Bob has shared with us that the heat may not present it self to be a problem.
If a cell gets too hot you may boil it producing a lot of water vapour.
Another consideration is plate area. You need to have enough plate area. The more you have the less problems you will have with heat building up at higher concentrations. Many of the chaep nasty cells on the market just heat up too much through lack of plate area.
Hope this helps
Mark

[weggl]

Dear Mark,
Thank you for your prompt reply. My cell size is 7x150mm x 150mm.
The plates were not cross hatched sanded (much to Bob’s disgust) bur rather sandblasted, the reason being that I don’t have a belt sander but I do have a sandblaster.
I am wondering why the water went dirty on 26% but was clean on 22%? The plates are 403SS.
I am also wondering if 0.8L/Min is ok for a 4 cyl Corolla?
The Lord willing this may be ok.

[weggl]

Mark,
one more thing i ran this cell at 10 amps for 5 hours on 22% and the temp only got to 48deg C.
Warren

[weggl]

Bob,
I did the cleansing for 3 days at 5 amps washed it out 4 times filtered the electrolyte first and got virtually nothing out of it. replace the electrolyte twice.
The blackish electrolyte came when i replaced the 22% with 26%.
I washed that out with distilled water ran it for 2 hours on distilled water which only had the minute residual electrolyte still in the cell it ran at 3 amps on 13,4 volts. that remained clear i emptied that washed it out and replaced it with 24% sod hyd it has been running now on 10 amps for 3 hours and is still clear. Guess I will just have to run it untill tomorrow morning and see what happens.
Thanks Bob.
Warren

[MarkinAustralia]

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