Reconditioning of photovoltaic solar panel

Reconditioning of photovoltaic solar panel

In the entry above on a photovoltaic panel manufacturing home and economically, was that cells, suppose that due to electrolysis, it factoring the silicone that was in contact with the cell in its compounds, turning it into a brown liquid mass blocking light, addition to almost all broke to dilate the polycarbonate and applied stress on cells.

Testing by the outline inner union
This time we are going to change the way of subjecting the cells to polycarbonate; first of all I made a test with a piece of 3 mm polycarbonate thick, pasting the cell only for inside corners:

I've left dry and then I have applied heat gun for all possible stress:

And the cell has not been able to cope with tension, breaking by where he had a small crack (look at the first photo).

The conclusion that I get with this is that If I apply a thin layer only in the corners and above, instead of inside, only to fasten to the polycarbonate and prevent the entry of water and dirt, can be enough already to just break them already partially damaged, as I said in the previous post.
The idea is to ensure not to damage any cell to weld the tracks so that they to not crack after.

I'm going to get to work and remove damaged 45 cells and paste new ones, just sticking them outside, of form that the elasticity of silica absorb dilatation of the polycarbonate.

By removing all the damaged cells of the polycarbonate

Using a spatula inox. sharp I have removed one to a cells; hard enough, so you have to arm yourself with patience.
As you can see in the photo, electrons scrap have silica in the center of all the cells, making it a Brown sticky paste, and even partially affecting polycarbonate.

Remove all traces of silicone I used acetone; cheap nail polish remover in an aerosol spray; applies enough quantity and left a time acting, then with a spatula out everything with ease.

Once clean polycarbonate plate, we prepare the cells in such a way that you only have to join the negative with the positive of another, since can not solder tracks directly over it.
I don't know if what I explained in the previous post, is suitable to weld the tracks to the cells on the top of a glass smooth and clean each, welding on the one hand the positive (which is the most difficult to make well) with the right thread and leaving the negative side a little longer together:

Stacked cells prepared for use
We put them in the panel as last time:

Once placed on the panel, suit, before welding, apply some silicone on the sides to be left fixed and that they do not move, and hardened once a few hours after we can already solder:

Then we apply a thin bead of silicone sealing well by the outline against the entry of water and dirt (although this side will not be so exposed to the inclemency of the weather, should leave it as best as possible).

Once the work is completed, I come to the Panel in a sunny spot and if possible without shadows.

Calculation of the optimum inclination of a solar panel
On the internet have spreadsheets that facilitate us the task, such as the European Commission on photovoltaic geographical information system, which tells us daily and monthly average production according to the month take account of geographical and climatic data (not only the latitude) to find an optimal tilt as tight as possible:

In my case I wanted to calculate how much would lose annual production if it placed the panels on the roof, and among the 14 of inclination of the roof and the optimum inclination of thirty-third production hardly varies 4% lower, so it's completely feasible to place them there.

With my latitude there is no much difference between put it between 14 ° and 50 ° tilt, by which we will have to assess whether we prefer that the monthly average is similar every month (or what it is giving priority to the produced in winter) with an inclination of 45 ° or more to take advantage of the winter light (produces 1% less in total for effects of temperature(, etc), or on the contrary prefer to produce more in the summer, approaching more the 15 degrees of tilt pointing South.

Logically, If we don't want to turn to network as it is our case, but decrease the minimum consumption (motor thermal ACS, refrigerators, appliances in standby, etc), is in the winter when usually consume more, by what resettle them with 45-50 ° in the wall.

Hanging wall panel
The ideal situation for panels is the roof, but given that I want to monitor this panel, and make it more accessible, in addition to providing me shade, I decided to put it on the balcony, where I can examine it.
As can be seen in areas that have been acetone acting, polycarbonate has begun to whiten superficially by the remains of acetone, however luckily this subtracted not just performance (5% maximum), so since I have relocated it to 3 weeks later continues to produce the same; 101W beak, which is not nothing wrong taking into account the "bleached" which has been (for a theoretical maximum of 150W lossless).

There is a small shadow of a phone cable that does not compromise too
If you look in the gray stripe I've placed an aluminum u-profile in one of the holes without cells to stiffen the polycarbonate, then doubled much with the heat under their own weight, which is subject to own polycarbonate with rosca-chapa screws and the sides.

The panel already hung in the Sun
Hold the panel I used small brackets of metal that can be purchased at hardware stores and warehouses of construction, and M8 screw with lock nut so that will not loosen over time.
I cut the corner of the tube square to allow movement at different angles when tie brackets to the wall.

Panel is fairly light, about 20 kg of weight that is easy to install with the help of a large staircase and some help; I've used tacos and large lag screws M6, drilling directly through the holes in the plates and screw a single screw on each side to hold and then finally two more on each side.

At the moment I have just placed a support to maintain the angle; to square tube I have welded you on one side a couple of pieces of plate with killed probes to allow turns without touching the plastic. They are made through holes with a drill bit Ø10 mm:

Support, with the paint still without applying photo
On this occasion, as I had already checked with the cell of the test, only those who already had early cracks have cracked (lack of care when soldering tracks) or which have hit unintentionally placing bracket, resulting partially damaged 4 or 5 of them, but that does not affect greatly its functioning (each cell produces 3, 5W maximumthe damaged surface of the total subtract).
However I am concerned that these cracks can enter dirt between the cell and the polycarbonate, it is possible to seal them slightly with silicone.

After a month the production stays, reaching 101W at times more Sun hours (unlike the last time, in hours of hot down to 20W spreading everything); I want to put another new polycarbonate panel to verify these initial results.