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Author Topic: Large Salt water battery ideas and questions  (Read 56485 times)

profitis

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Re: Large Salt water battery ideas and questions
« Reply #45 on: August 15, 2013, 07:08:04 PM »
lol yes..it will be of great value for survival skills to watchers

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #46 on: August 15, 2013, 07:20:42 PM »
dont use brass as your cathode.brass is 40% zinc.use pure copper
Will probably wind up using either plumbing copper or ground pipe stuff.  It's readily available and not so heavily alloyed .

SeaMonkey

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Re: Large Salt water battery ideas and questions
« Reply #47 on: August 15, 2013, 08:39:30 PM »
Quote from: Mungo
SeaMonkey is your objection to these batteries power density or is it...

Not an objection really, since these kinds
of voltaic cells do have their place;  I'd think
of it as more of a preference.  I do have a
supply of materials for when I may need
them.

Chemical cells of the primary variety require
a lot of work in fabrication and maintenance
to keep them "humming."  Eventually it grows
tiring.  And there is the never ending need for
suitable metals to replace the electrodes as
they are either eaten away chemically or
otherwise deteriorate.

Once one has learned how they work and
how much it takes to keep them functional
the fun slips away and it becomes work.

Re-chargeables are just so much easier
to make use of and with proper care will
last many, many years.  I've come to really
appreciate low maintenance sources which
don't require too much work and attention
and have the oomph to handle most tasks.
 
As we get on up in years we tend to gravitate
to the easier ways of doing things... ;)

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #48 on: August 16, 2013, 12:46:12 AM »
 :o
okay, just did a little experiment. 8oz salt water at 1.038 sg.  Aluminum anode immersed and copper cathode immersed: .44 volts.  Aluminum anode immersed and copper cathode essentially floating on the surface on a cloth hammock, .78 VOLTS!  Yeow.

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #49 on: August 16, 2013, 01:03:59 AM »
Here's the two shots, one with the electrode immersed, one with it suspended on a wet cloth at the top of the electrolyte.  Now, how do I adapt this to something more permanent..... :-\

SeaMonkey

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Re: Large Salt water battery ideas and questions
« Reply #50 on: August 16, 2013, 03:45:23 AM »
Aren't electro-chemical experiments fun!(?)

Surprising too.

Here's one man's solution from long ago.

profitis

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Re: Large Salt water battery ideas and questions
« Reply #51 on: August 17, 2013, 06:43:06 PM »
are those 2 shots with caustic soda added?

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #52 on: August 18, 2013, 12:34:42 AM »
no.  I added a small amount of bicarbonate of soda to make it a bit more alkyline, but no caustic soda.

New battery test monday on a larger cell.

Any suggestions on the best way to check current on a .6 watt or so cell, what kind of load, etc etc.?

profitis

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Re: Large Salt water battery ideas and questions
« Reply #53 on: August 18, 2013, 03:30:15 PM »
i would suggest to make cells in series and to put caustic soda in there @mungo.caustic soda will attack your anode much better and produce more potent power.baking soda is too mild alkaline.an electric toy motor is a exelent way to chek power levels as it will work under its recomended voltage and draw large currents.

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #54 on: August 19, 2013, 02:28:27 AM »
will try the motor idea....Im hoping radio shack may have some, not sure where else around here might unless I buy some cheap toy and cannibalize it.

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #55 on: August 19, 2013, 10:00:37 PM »
Okay here's some shots of the new cell
 The cathode is a series of 1/4" copper tubes, lightly sanded and bound around a polyester wick.  The anode is a bundle of aluminum tubes.

The solution in the cell tank is 1.030 sg sea salt.  The cathode lies on top of the tank lid with the wick down in the electrolyte solution.  The anode is, of course, below, fully immersed in the electrolyte.  The additional red lead on the cathode is me beginning to set up a load test and is not connected to anything in this shot.

Voltage started at .58/watt, but climbed almost immediately to .75 watt and stabilized.  Using a small dc motor as load, amps read as 5.23 on the 20mA range.  More in a bit as soon as I determine how stable this is.

After this has run for a bit, I will try, as per suggestions, some caustic soda in the mix.

More in a bit.

profitis

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Re: Large Salt water battery ideas and questions
« Reply #56 on: August 19, 2013, 10:46:40 PM »
amazing the difference on air exposure makes.now watch what happens when you throw some(not too much)NaOH.

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #57 on: August 19, 2013, 10:49:14 PM »
 :(  Have to go buy some first :)

Not at all sure what Im seeing with the amps.  The voltage is insufficient to power the little motor, so its mostly acting as a resistor.


profitis

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Re: Large Salt water battery ideas and questions
« Reply #58 on: August 19, 2013, 10:58:39 PM »
its the aluminum oxide layer hampering the voltage,you have to throw caustic @mungo.put two or 3 cells in series to get a motor going.you can also scrape loudspeaker wires on there to 'hear' the power ratings,the more power the louder the scratch sounds

Mungo

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Re: Large Salt water battery ideas and questions
« Reply #59 on: August 20, 2013, 12:02:10 AM »
well. humpf.  Added the  :o caustic soda and the voltage actually DROPPED to .70.  Hmmmm  ....anyone care to speculate A) why and b) how much amperage this thing could actually pull per cell?