Why does not my 100W Solar Panel fail to charge my two small 12 40Ah solar batteries?

[SEIRMIC]

your photos dismiss my first concern: there is no shade, unless you hide from us a large building just next to the sign

count cells ... easy for large panels which have square cells ... but 100w is a small panel which has small cells made with large ones cut into pieces, so rectangular cells not easy to identify on the photo ... but whatever, your label shows that its optimum voltage is 18v, so it can be used to charge a 12v battery

what worries me a lot more about your photos is these traces like large cracks on many cells

and I always come back to the same thing: MEASURE THE CURRENT! there is only the measurement of the current which will allow to advance, to know if your panel works or does not work

dear chatelot
nothing like shadow
the measurement made: 1,46 A
Thank you

[chatelot16]

1,46 A x 12V = 17,5 W ... we are far from 100 W

so if you made this measurement at one hour of full sun there is a big problem!

you have to see if it comes from the regulator, the battery, the wiring or the panel

solution: measure the short circuit current of the panel: the short circuit of a panel is harmless because its short circuit current is only slightly higher than its nominal current, therefore without danger ... measure the short circuit current of the panel allows you to check a panel without having any doubts about the other elements of the installation ... if the short circuit current is also low it will be proof that the panel is worth nothing

[izentrop]

Hi,
The panel includes 2 X 20 cells in series, which explains the 20 V no load.

The midpoint of the diodes is not connected, preventing protection in the event of partial shade. It must be connected to the middle point at the top of the panel, but that is not what creates the current problem.


The problem probably comes from broken cells which create a current throttle.
We see that some breaks have been plugged with a bead of silicone, but it is useless because the electrical connection is broken and part of the cells is no longer connected. The current is that of the weakest cell.
We should at least change the broken cells and it is not an easy task.

There are lots of videos on the tube showing how to weld cells.

[SEIRMIC]

Hello
Thank you very much
it would be better if I bought a panel and throw it away because here, it will not be easy and the false repairers will swindle me.
Thank you again for everything, thank you for taking the time to explain myself, Izentrop thank you I learned a lot from a solar panel thanks to you, the volt and ampere measurements, the cells on a panel ... ..Thank you very much for the knowledge.


Very good continuation to all.

[Did67]

I also think that everything leans in favor of an overly damaged panel ... (this was fairly quickly the dominant idea in this discussion)

Since you can now measure the intensities, a word of advice: if you buy one, test it in front of the store before paying for it !!! (sometimes the faults are not as visible - it may be a bad weld).

[izentrop]

Hello,
Do not throw ... In your country, a repairer can repair it for less than a new one I think.
I only see 7 broken cells out of 40 in this photo.
and as Did67 says, before you buy or take it back after repair, you need to check the short-circuit current.

You keep only the most efficient of your regulators, a PWM or better an MPPT and especially not to connect the batteries without and do not forget to dust it from time to time.

[SEIRMIC]

Hello,
Do not throw ... In your country, a repairer can repair it for less than a new one I think.
I only see 7 broken cells out of 40 in this photo. (...)
You keep only the most efficient of your regulators, a PWM or better an MPPT and especially not to connect the batteries without and do not forget to dust it from time to time.

Hello

Thank you very much I just read you after long absence.Thank you but I changed it, I have a new topic of discussion, I ask your point of view, thank you in advance

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