6x6 poly solar cells tabing

[inetdog]

i understood that, though in my openion first it looks like short circuit if you ignore the ammeter device circuity inside

so 1.43 is false and the result should be higher, ? or lower i had the ammeter plugged in directly no load nothing

sorry for asking all these questions just thought they are related to the subject , now i'll quit asking and learn " from the internet" really time is not worth it i just need the basics

thanks again appreciate all your help and everyone's help

When you want to measure the short circuit current, you want a short circuit.

If the maximum current you get is 1.43A, then at least one cell is defective and is limiting the current through the series string. If you have bypass diodes in place, then all of the sections but one are likely to have bad cells and be bypassing current through the diode. The remaining section then also has at least one bad cell, but the bypass diode is not conducting since that is the only segment left and has a current limit that is higher than the other sections.
The panel is useless unless you are able to identify and replace or short out the bad cells.
You always want to test each cell before tabbing, and then test again after tabbing and before encapsulation. Any cells that are visibly cracked after tabbing should be replaced immediately if you can, and shorted out if you cannot replace them.

[a7m1]

If you connect the ammeter directly from the panel + to the panel -, the ammeter itself is the close to zero ohm load. Since it is close to zero ohms, it does not absorb a significant amount of power, and the panels are not delivering more than a tiny amount of power, just current.

I think you would benefit from a basic course in electricity at this point, if you have that resource available.

i understood that, though in my openion first it looks like short circuit if you ignore the ammeter device circuity inside

so 1.43 is false and the result should be higher, ? or lower i had the ammeter plugged in directly no load nothing

sorry for asking all these questions just thought they are related to the subject , now i'll quit asking and learn " from the internet" really time is not worth it i just need the basics

thanks again appreciate all your help and everyone's help

[inetdog]

If you connect the ammeter directly from the panel + to the panel -, the ammeter itself is the close to zero ohm load. Since it is close to zero ohms, it does not absorb a significant amount of power, and the panels are not delivering more than a tiny amount of power, just current.

I think you would benefit from a basic course in electricity at this point, if you have that resource available.

[a7m1]

A wire is a perfectly good ~0 Ohm resistor. In other words, wire the panel straight to the ammeter.

And I do not know of any meter that "takes its own load into account when displaying the measurement" for the simple reason that it cannot detect the characteristics of the rest of the circuit and so would not know how to correct, even if it were appropriate.
The burden is on the user to know the limitations of their tools.

i thought of something that add up it's own usage or something

so i can get the current reading by wiring ammeter directly (This is what i thought of and did) was only 1.43 A !!!!! must be because of all cracked cells and bad tabbing

how can wiring an ammeter tells me how much current i am producing? there isn't any load that gets the voltage close to 0V


i am really confused here

and about wiring junction box how can i do it? i did it already
my junction box has 2 diodes and 3 terminals

1 2 3
diode| diode|
1 2 3

the "|" indicate the polarity or whatever with diodes
i get half the voltage by getting power from 1 and 2 terminals
and full voltage by 1 and 3 terminal

everything correct here?

thanks alot for follow ups

[inetdog]

so what would be a good load? do i get the voltage down to "Zero" or close to zero?
any specific resistor to do the trick ?

A wire is a perfectly good ~0 Ohm resistor. In other words, wire the panel straight to the ammeter.

And I do not know of any meter that "takes its own load into account when displaying the measurement" for the simple reason that it cannot detect the characteristics of the rest of the circuit and so would not know how to correct, even if it were appropriate.
The burden is on the user to know the limitations of their tools.

[a7m1]

The current certainly can be high at close to zero voltage. It will take a small number of millivolts to drive current through your ammeter, but that does not affect the measurement much. Isc is the current into as short a circuit as possible.
Similarly, Voc is the voltage with nothing connected but a voltmeter. A little bit of current will flow through the meter, but not enough to invalidate the measurement.
To fully check cell performance (and in particular to test panel performance when bypass diodes are in play) you have to measure current and voltage in the same circuit which loads the panel down to its maximum power point for whatever light level is falling on it.

The cell substrate is silicon while the glass is mostly silicon oxide. Very similar coefficients of expansion.

i am assure multimeter will account for it's own load when displaying the measurement

so what would be a good load? do i get the voltage down to "Zero" or close to zero?
any specific resistor to do the trick ?

how to wire the junction box?

i have one close to this

how-to-get-connection-from-solar-panel..Back-Side-of-The-Solar-Panel-Junction-Box-and-The-Functi.jpg
same diodes polarity too
i think i have the negative on the left and positive on the right

not really sure though

[inetdog]

The current certainly can be high at close to zero voltage. It will take a small number of millivolts to drive current through your ammeter, but that does not affect the measurement much. Isc is the current into as short a circuit as possible.
Similarly, Voc is the voltage with nothing connected but a voltmeter. A little bit of current will flow through the meter, but not enough to invalidate the measurement.
To fully check cell performance (and in particular to test panel performance when bypass diodes are in play) you have to measure current and voltage in the same circuit which loads the panel down to its maximum power point for whatever light level is falling on it.

The cell substrate is silicon while the glass is mostly silicon oxide. Very similar coefficients of expansion.

[a7m1]

Anything smaller than 6" X 6" will be easier to deal with. Bonding cells to anything but
glass might cause cracking in sun, with the different coefficient of expansion. Better
study up on Ohms Law and how to use a meter. Bruce

so i can assume that glass and solar cells expands at about the same rate right?

i know that i can hook a multimeter in series with a load and get the amps
then probably hook another multimeter to get voltage and multiply them{volts X amps} together to get watts

my question is how to perform all these tests?
current at short circuit
and other stuff
can the voltage be at 0 while producing current??

thanks again bruce <3

[bcroe]

so 12v output or whatever outputs i get by connecting loads (volts times resistence of loads = amps)
any other easier way to verify amls output? i have a digital multimeter ready
can i plug multimeter to read voltage then add loads untill i get 12v output theb hook mulitimeter inline with loads this gives me 12v amps output, is it a good indication?
i'll try to enforce the cells to the back of the panel (wood)
how did they cracked from strong sun, ? rain came after lots of heat? thrrmal stress or something?
several months is good for me untill i get a good setup to begin with professionally
Any sized cells that you recommend which is easy to handle and less prone ti crackes during assembly?

Anything smaller than 6" X 6" will be easier to deal with. Bonding cells to anything but
glass might cause cracking in sun, with the different coefficient of expansion. Better
study up on Ohms Law and how to use a meter. Bruce

[a7m1]

If you have 12 volts across 100 ohms, Ohms law tells you the current is 12V/100ohm = 0.12A.
Tie 3 more in parallel each carrying the same current, and you have 0.48A. Cracked cells I
short out. I have no idea how long a cell lasts in the weather, maybe months. But if not
properly encapsulated to glass, it could crack the first time it sees strong sun (happened to me).
Bruce Roe

thanks Dear Bruce,

really appreciate your continuos support.

so 12v output or whatever outputs i get by connecting loads (volts times resistence of loads = amps)

any other easier way to verify amls output? i have a digital multimeter ready

can i plug multimeter to read voltage then add loads untill i get 12v output theb hook mulitimeter inline with loads this gives me 12v amps output, is it a good indication?

i'll try to enforce the cells to the back of the panel (wood)

how did they cracked from strong sun, ? rain came after lots of heat? thrrmal stress or something?

several months is good for me untill i get a good setup to begin with professionally

Any sized cells that you recommend which is easy to handle and less prone ti crackes during assembly?

[bcroe]

how to measure current using a digital multimeter
mine is proskit branded has 10a scale and several ma scales

i always read that i plug the multimeter in serial with the load but what ifi wanted to know the maximum output, increase the koad untill i get 0 volts output?? i only have 1 digital multimeter right now

roughly how long will uncovered cells last, assuming i got good enforcement of the cells

and what to do to severly cracked cells, short them?

If you have 12 volts across 100 ohms, Ohms law tells you the current is 12V/100ohm = 0.12A.
Tie 3 more in parallel each carrying the same current, and you have 0.48A. Cracked cells I
short out. I have no idea how long a cell lasts in the weather, maybe months. But if not
properly encapsulated to glass, it could crack the first time it sees strong sun (happened to me).
Bruce Roe

[a7m1]

If the cells are not encapsulated, they will have a very short life indeed. If cells are
cracked, the current will be greatly reduced from the 8A possible. Look for a load that
will pull the voltage down somewhat; maybe a 100 ohm 5 watt for openers. Attach
several in parallel till voltage starts to drastically drop. Get the bad cells out. Bruce Roe

dear Bruce,

how to measure current using a digital multimeter
mine is proskit branded has 10a scale and several ma scales

i always read that i plug the multimeter in serial with the load but what ifi wanted to know the maximum output, increase the koad untill i get 0 volts output?? i only have 1 digital multimeter right now

roughly how long will uncovered cells last, assuming i got good enforcement of the cells

and what to do to severly cracked cells, short them?

[bcroe]

i wasn't ready to do anything and got the cells by the mail
I didn't even incapsulated it kr cover it, how bad it'll get if it got dust and rain over it?
I understand that there is no electronics just electricity will anything rust up?
even the cells are not glued in place and alot of them cracked during tabing or assembly
I'll try to re-enforce the cells into place then do any test

Can you give m a good load to try out? I tried to connect a 65w invertor while voltage
was about 16-18 and it didn't do anything. I tried the same thing when voltage was
around 15 or so and it dropoed to sub 1-volt. The invertor was not loaded at all.

btw how to test amps output? do you have to get the voltage to 0? short circuit?

I tried to hook up my multimeter(it's digital one) and was on 10A setting. It shows
1.43 A. thanks again for your support

If the cells are not encapsulated, they will have a very short life indeed. If cells are
cracked, the current will be greatly reduced from the 8A possible. Look for a load that
will pull the voltage down somewhat; maybe a 100 ohm 5 watt for openers. Attach
several in parallel till voltage starts to drastically drop. Get the bad cells out. Bruce Roe

[a7m1]

I would connect a light load that lets the output stay above a dozen volts under steady sun.
Then check the voltage of each column of 8 cells, or maybe 4 at a time; each group
should be close to the same voltage. If you find some poor performers, try to narrow it
down to a specific cell. Do observe polarity; reverse voltage on a cell means it is holding
up the rest. Jumping out a bad cell is better than letting it further reduce output. Bruce Roe

Thanks bruce,

This setup was very poor and it was my first panel

i wasn't ready to do anything and got the cells by the mail
i didn't even incapsulated it kr cover it, how bad it'llget if it got dust and rain over it?
i understand that there is no electronics just electricity will anything rust up?
even the cells are not glued in place and alot of them cracked during tabing or assembly


i'll try to re-enforce the cells into place then do any test

can you give m a good load to try out?
i tried to connect a 65w invertor while voltage was about 16-18 and it didn't do anything
i tried the same thing when voltage was around 15 or so and it dropoed to sub 1-voltthe invertor was not loaded at all

btw how to test amps output? do you have to get thr voltage to 0? short circuit?

i tried to hook up my multimeter(it's digital one) and was on10A setting it shows 1.43

thanks again for your support

[bcroe]

Testing Output

Got 17.17 volts unloaded and 16.98 loaded with motorola microusb charger tbat outputs i believe 500mah 5v and accepts inout 10.08-33 dcv not bad after all, I managed to run 5 meters 3528 strip and voltage dropped to 7 in roomlight only unloaded voltage was 10-11v just in room light !!!

I would connect a light load that lets the output stay above a dozen volts under steady sun.
Then check the voltage of each column of 8 cells, or maybe 4 at a time; each group
should be close to the same voltage. If you find some poor performers, try to narrow it
down to a specific cell. Do observe polarity; reverse voltage on a cell means it is holding
up the rest. Jumping out a bad cell is better than letting it further reduce output. Bruce Roe