Solar to mineral accretion underwater!

[Sunking]

Ok so the person reading my stupid readings is retarded!!!!! Was not doing it properly,

So here we go,
1.2v
1.8A on 10A setting

This is at the panel, so does that mean it should be the same at the structure? If so that is basically spot on what I want no matter how inefficient,

OK that sounds correct. It means the total resistance is .67 Ohms which consist of the wire resistance plus the electrode resistance .

This is at the panel, so does that mean it should be the same at the structure? If so that is basically spot on what I want no matter how inefficient.

No it does not. The current is the same, but not the voltage. There are two units of resistance at play here. All we know is the total resistance. The two units of resistance in the wire, plus the sea water resistance between the two electrodes. Can you pull the wires out of the water and short the leads together? If so then use the panel to measure voltage and current again as you did before. . The resistance is too low for your meter to read accurately.

So for example you might read .95 volts and 1.9 amps = .5 Ohms. That would meas the seawater resistance = 0.17 Ohms. That would mean with 1.9 amps of current the voltage between the electrodes is 1.9 x .17 = .323 volts.

[Solar_Marine]

Ok I won't be able to do that for a few days, but I will and report back, do you mean pull the structures out of the water and test it or just the wires?

Some questions if its ok,

Will a solar controller help me?

Could I add the exact same panel and up the voltage getting to the structures?

Thanks,

[Sunking]

Ok I won't be able to do that for a few days, but I will and report back, do you mean pull the structures out of the water and test it or just the wires?

Just the resistance of the wires. We know total resistance Rt = Rw + Re

Where Rt = total resistance
Rw = wire resistance
Re = electrode resistance.

If you know Rt and Rw then we can calculate Re.

Some questions if its ok,

Will a solar controller help me?

Could I add the exact same panel and up the voltage getting to the structures?

Thanks,

You stated 1.23 volts was optimal at the electrodes. Once we know the Re and RW then you design a converter to supply 1.23 volts at the electrodes. The supply voltage will be greater than 1.23 volts

[Solar_Marine]

Sunking! Thank you sir! (madam..?)

You have helped so much!

One last one, stupid one,

When you mean short them what does that mean exactly and how would I use the multimeter to read v/a?

Thanks,

[Sunking]

Sunking! Thank you sir! (madam..?)

Name is Dereck if that helps you determine gender.

One last one, stupid one,

When you mean short them what does that mean exactly and how would I use the multimeter to read v/a?

It means when you pull the 2 wires up, you connect the ends together to make a Short Circuit or Zero Ohm's. You would then measure the voltage and current at the panel like you did before. You should see around 1 to 2 volts and a current of 1 to 3 amps assuming you have bright noon sun. You are making a Low Resistance Ohm Meter out of your DMM using current and voltage.

You meter has a Resistance scale, but uses a very low current supply of about .001 amps. So when you measure resistance you are actually reading voltage with .001 flowing through a resistance. Well that is fine if you are working with 10 ohm's or higher. Example a 100 Ohm resister with .001 amps flowing develops .1 volts and your meter scale table would convert that to 100 Ohms because the current is fixed at .001 amps.

But to measure low resistance we want to use as much current as possible to achieve the most accurate reading we can. So in essence 1 amp is 1000 times more accurate the .001 amps. So you will see amps of 1 to 3 amps at a voltage of 1 to 2 volts. Say you get 2 amps at 4 volts. R = 4 volts / 2 amps = .5 ohms. If you used your meter resistance measurement at .001 amps would only develop a voltage of .0025 volts which is lower than your meter can measure accurately.

[Solar_Marine]

Bingo, Got it,

Thanks Derek,

So how would making a controller help this whole situation? Pushing more volts through the wire? Surely in full sun this panel is pouching through as much as it can anyway, does this mean I would need a second panel for sure?

Thanks,

[Sunking]

Bingo, Got it,

Thanks Derek,

So how would making a controller help this whole situation? Pushing more volts through the wire? Surely in full sun this panel is pouching through as much as it can anyway, does this mean I would need a second panel for sure?

Thanks,

Right now what you have is a Current Source with a 22 volt battery pushing current through variable resistor of 7 to infinite Ohm Resistor of internal resistance. The value of the variable resistor is dependent on the amount of sun light striking the panel. At night that resistor is open circuit or infinite resistance and thus no current flows or voltage is developed. Screw that you won't understand.

You need a Buck Converter controller which acts like a DC transformer to step down the voltage and step up the current. The actual voltage will depend on the wire resistance and electrode resistance. So lets say the electrode resistance = .2 Ohms and you want 1.3 volts on the electrodes. That tells us down in the water we need 1.3 volts @ 6.5 amps (8.45 watts). Second assume the wire resistance is .3 Ohms with 6.5 amps flowing dropping 1.95 volts. So you would need a converter to step down to 1.3 volts + 1.95 volts = 3.25 volts. So anytime your panel produce 21 watts or higher your circuit works. Anything under 21 watts and the circuit turns off because there is not enough energy to drive it.

The just is you need a converter to match the source resistance to match the load resistance. The challenge with solar is the source resistance in dynamic constantly changing from 1 minute to the next.

If it were me designing this I would be using several hundred watts of panel charging a 12 volt large capacity battery. Then supply the electrodes whatever voltage you wanted assuming no higher than 6 volts using a 4 point bridge circuit. That would keep the electrode voltage at exactly where you want regardless of conditions 24 hours a day.

[Solar_Marine]

Ok so this is just to help me understand, (i have learnt a lot)!

Our resistance we have in this case is lets say 0.67,

Say 0.17 is the wire and the 0.5 left is the anode/cathode,

How can this help us work out what I need? Surely all you need to know is the total resistance.... of 0.67?

I am stuck on how the resistances figures above can help you work out what current and voltage you want coming from the panel?

Also, what would happen if we did just connect another identical panel in series?

[Solar_Marine]

[QUOTE=If it were me designing this I would be using several hundred watts of panel charging a 12 volt large capacity battery. Then supply the electrodes whatever voltage you wanted assuming no higher than 6 volts using a 4 point bridge circuit. That would keep the electrode voltage at exactly where you want regardless of conditions 24 hours a day.[/QUOTE]

Ideally that would be great however we only had a very select funds and it is Fiji! However the ideal voltage of 1.23v is 'ideal' however it has been worked with voltage up to 12v! Most projects I have read about use just a solar panel straight to structure, like this one.

Maybe ours is working but very slowly due to the minimal voltage reaching the anode and cathode, after all the aluminium is bubbling and corroding. I just more want to understand it all properly and then work out if we can make it more effective/get more voltage to the structure.

[Solar_Marine]

does this help you at all,

a small paper on it......?

http://www.itk.fpik.ipb.ac.id/ej_itk21/jurnal/1_biorock_b.pdf

Seems like 2 - 3 amps is ideal with low voltage

[sensij]

does this help you at all,

a small paper on it......?

http://www.itk.fpik.ipb.ac.id/ej_itk21/jurnal/1_biorock_b.pdf

Seems like 2 - 3 amps is ideal with low voltage

Listen, I just read your updated readings. While Sunking has shared a lot of good information, I don't think any of it really applies to you. The current is low enough and your wire resistance is low enough that what you are reading at the panels is a good indication of what is happening at the anode and cathode. If you are hitting your target values, even if it somewhat inefficient, no reason to change anything.

[Mike90250]

Why your electrodes are getting eaten away - dissimilar metal corrosion

Steel and Aluminum:

http://en.wikipedia.org/wiki/Galvanic_corrosion#US_Navy_Littoral_Combat_Ship_Independence

Gonna cost big to fix that blunder.

And the other answer, is you are "electroplating" the aluminum to the steel. reversing the circuit polarity may retard the action, but it may not biologically, be the effect you want.

[myfriendSUN]

Ok, yeah yeah I understand that, another poster asked me to check the panel with nothing connected,


So tested again,
1.5v coming out
at 0.9A on a 20m setting on multimeter (peaked at 1)

What is 0.9amps on that setting?

Your reading was 0.9mA which is equal to 0.0009A.

[sensij]

Why your electrodes are getting eaten away - dissimilar metal corrosion

Steel and Aluminum:

http://en.wikipedia.org/wiki/Galvanic_corrosion#US_Navy_Littoral_Combat_Ship_Independence

Gonna cost big to fix that blunder.

And the other answer, is you are "electroplating" the aluminum to the steel. reversing the circuit polarity may retard the action, but it may not biologically, be the effect you want.

There is no evidence of a blunder, the behavior at the anode is as expected. The build-up at the cathode is occurring slower than expected, but aluminum and steel are a proven pair for this system (as published in the paper linked by the OP).

More guesses as to the slow build-up on the cathode
1) The surface area of the electrodes is not matched to the current... in other words, you are generating what you think is the right current, but the current density is wrong.

2) There is something like a ground fault occurring. To test for this, you could measure the current on the + side and then measure it again on the - side. If the current measurements are unequal, you are getting leakage somewhere.

[Sunking]

2) There is something like a ground fault occurring. To test for this, you could measure the current on the + side and then measure it again on the - side. If the current measurements are unequal, you are getting leakage somewhere.

That is impossible to happen. The whole system is one huge ground fault, and the source of energy is the panel and Mr Kirchoff Law applies to any power system. All current leaving the panel returns to the panel. Basically it is a Cathodic Protection System on a very small scale.