Solar to mineral accretion underwater!

[Solar_Marine]

Ok guys, thank you for the help, I am not sure I understand exactly everything that you have said,

However I will try extract some parts,

First off if I get a controller will this help my cause? So my understanding is the controller will take my panel voltage and change it into a consistent or near constant 12v.....which I can then send down the wire to my rebar?

How do I measure the resistance of my wire?

I am testing the panel in a minute regarding amps,

I am not sure I understand, if my wire is pretty thick (16mm) then surely more current should be able to travel down the wire..? At the start of the whole project I was worried about too much voltage..?

[Sunking]

Sensi and BC you guys are missing one very important fact. He is measuring 1 to 2 volts at the panel right?

Ask yourself why it is so low when connected to the wiring and electrode? It is not because his wiring is too small or long causing high resistance. It is because the resistance is way too low shorting out the panel forcing it into a pure current source mode well below MPPT. If he makes the wire larger or shorter his voltage will go lower. He wants a VOLTAGE SOURCE not a CURRENT SOURCE.

Marine guy when you get back to the site do this. Monitor the current and voltage simultaneously throughout the day to establish a resistance. For example if at one point in time you measure 2 volts and 2 amps then R = 2 volts / 2 amps = 1 Ohm. One you get a grasp of what resistance your are operating into then you can determine the correct VOLTAGE SOURCE you need. You should notice the resistance will be pretty much fixed depending on water temperature. Look up Oh's Law and the 12 equations, then work a few equations to see the relationship of power, voltage, current, and resistance. Your 50 watt panel will only work with a resistance of about 6 ohms and higher for maximum power as a voltage source. You are trying to operate at around 1 ohm or less. At one Ohm the highest voltage you will ever rarely see is 2 to 3 volts on a bright sunny day at noon. Current x Resistance = Voltage or 3 amps x 1 Ohm = 3 volts. Ohm's Law.

The only fixed variable you have is RESISTANCE with a variable current being pushed by a limited voltage of VOC. You want a fixed voltage able to operate into a very low resistance of less then 1 Ohm. You need to understand the difference between a current source and voltage source. You panel will only behave if the total load resistance is greater then 6 Ohms to open circuit.

[Solar_Marine]

Ok that makes sense sunking thank you,

Just so you have it,

Disconnected it all, plugged the multimeter into the panel,

21v
2.4amp

plugged everything back in and came out at 2.5v,

Just so I am doing this right also, to measure the amps when the system is connected, I take out the positive terminal from the panel and use the mutimeter to connect the circuit?

[Solar_Marine]

ok so back logging my readings I think it is around 2 ohms resistance

[Sunking]

ok so back logging my readings I think it is around 2 ohms resistance

Read my last response again. I edited it.

[Sunking]

Disconnected it all, plugged the multimeter into the panel,

21v
2.4amp

Read this stickie. Disconnect the panel from the wire, and set your meter as shown. In Voltage you are measuring Voc meaning voltage open circuit with no current. When you measure current you are measuring Isc or short circuit so there is no voltage. That does not tell you what the current is with a load connected, which is what you want. To measure current your meter has to be part of the circuit in series. Do you understand?

To measure load current you leave one wire connected to the panel. With the other wire you use your meter as a wire to connect to the panel so current runs through the meter. One meter lead to the disconnected wire, and the other to the panel to complete the circuit. Understand?

[Solar_Marine]

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?

[Sunking]

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?

If it says 20 ma means full scale is 20 mill-amps and ,9 would mean .009 amps. It has to be much higher than that to pull the panel voltage that low. Gotta run, be back in an hour.

[sensij]

If it says 20 ma means full scale is 20 mill-amps and ,9 would mean .009 amps. It has to be much higher than that to pull the panel voltage that low. Gotta run, be back in an hour.

Right, now you are seeing what you are missing. Nothing about what has been posted suggests that it is operating in constant voltage mode, other than the low voltage. The measured current is too low. The measurements made with the panel short circuited also do not make sense. There should be 0 volts, and something on the order of Isc for current. The meter is being used incorrectly, or the terminations are messed up. Getting Voc correct and nothing else right suggests that current flow is not occurring as it should from the panel alone. None of the rest of the system matters until the panel characterization yields good measurements. I'm unavailable for a few hours, hopefully the OP can read the manual on his meter and see what is up.

Spending money on 200 ft of 16 mm copper suggests there is some money being spent here, you would have to believe that decent measuring equipment is available.

[Solar_Marine]

Ok so tested again, voltage was 0.3 and the current 0.2 at 20m!!

What the hell is going on?

[Solar_Marine]

Right, now you are seeing what you are missing. Nothing about what has been posted suggests that it is operating in constant voltage mode, other than the low voltage. The measured current is too low. The measurements made with the panel short circuited also do not make sense. There should be 0 volts, and something on the order of Isc for current. The meter is being used incorrectly, or the terminations are messed up. Getting Voc correct and nothing else right suggests that current flow is not occurring as it should from the panel alone. None of the rest of the system matters until the panel characterization yields good measurements.

All I did was disconnected all wires and put red multimeter wire in (+) and black multimeter wire in (-).......

[sensij]

All I did was disconnected all wires and put red multimeter wire in (+) and black multimeter wire in (-).......

20m suggests a 20 mA scale. You need a measurement scale that could handle 7 amps. You might have damaged the meter already by putting too much current through the low current setting. Does it have a higher current setting? Usually that is a different fuse, and it might still be OK.

[Solar_Marine]

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,

[bcroe]

20m suggests a 20 mA scale. You need a measurement scale that could handle 7 amps. You might have damaged the meter already by putting too much current through the low current setting. Does it have a higher current setting? Usually that is a different fuse, and it might still be OK.

Yes, or maybe there is a short in the wiring. I really don't like inserting ammeters
into circuits; much prefer a clamp on or a shunt. Bruce Roe

[Solar_Marine]

Sunking, any thoughts on the last figures I posted, works out at a resistance of around 0.6

Would the anode and cathode be seeing the same voltage/ampitude?