How to Wire Solar Cells

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By CWilliams
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Solar Cells

Learn to wire your own solar cells. Solar is becoming more popular, however, the price is enough to deter most people from buying into the dream. You can make your own solar panels cheaply, with the use of simple tools. Wiring solar cells is a cheap way to produce homemade solar panels. Get off the grid today buy making your own solar panel!

Difficulty: Moderate

Instructions

Things You'll Need:

Solar cells
pen style soldering gun
copper wire 2 gauges
plywood
glass
caulk
UV Guard

Step 1

Front and back view of soalr cell

The purpose of this "how to" is to explain how to wire solar cells correctly. I will post a "how to" for the assembly portion of this project so you can make a solar panel from your assembled solar cells. In the resources section there will be links to video, as well as other useful information.
Step 2

Tabbed back cell

Above you can see a front and back view of a solar cell. Depending upon what type of solar cell you buy you will either have clear lines like the ones pictured or you will have tabbed cells. The tabbed cells look very similar except that the back will have metal squares instead of full lines. Both types of solar cells will work for building your own solar panel. I need to note now that you must stay consistent in size of solar cells as well as energy output, this is to say that all your solar cells should be rated to produce the same amount of energy. Broken solar cells (chipped or damaged)will still work fine for a homemade solar panel however they are harder to use your first time so I recommend working with used undamaged solar cells.
Step 3

Series

Use enough copper wire to flow the length of your cell series so that you are essentially using the same piece of wire for every panel in that row. There is a wiring gauge guide in the resources section.
Step 4

Pen style Soldering Iron

When soldering your copper wire to your solar cells you will use an acid core solder. This material is cheap and easy to work with. Solder in a good solder gun will flow very freely so it is important to take care and get it only on the spot where it should go. I recommend using a pen type soldering gun to join solar cells as this makes application very easy.
Step 5

panels that come with conection ribbon attached alreay.

The solar cells will be wired in a series starting and ending with the same polled solar cell. If you start with a positive solar cell you end with a positive cell, the same applies to a negative series. The front of a solar cell is the negative side, the back is the positive side. When you are attaching your copper wire with solder you determine the poll of your solar cell. If you solder copper wire to the front of your solar cell you will be starting the series with a negative cell. You would solder the next cell in the series on the back to produce a positive alternating until you end with a negative.
Step 6

Panels Produced

The points on your solar cell where you attach solder and your copper wire should be slightly silver. If these points are white you can lightly scratch them with the blunt end of a pair of tweezers. This step is crucial to getting a solid contact on the solar cells.
Step 7

Wiring a Series

You will always have an odd number of cells in a series, what you start with is what you end with, and you will always have an even amount of series that make up your panel. A solar array can be made up of a number of panels to produce the amount of electricity you need. Look at the wiring diagram to see how the solar cells are wired into a series.
Step 8

Positive and Negative polls

Notice that the positive and negative wired series are on opposite sides of the panel this is because you do not want these wires to accidentally touch one another. All the solar cells are facing the same way, I colored the diagram differently so I could show you the under over or over under wiring pattern.
Step 9

Over and Under explained

I have included a diagram that more clearly identifies where your top soldered and bottom soldered wires should be in a solar cell. This is a very hard thing to teach in a 2d application. I hope that the inclusion of this diagram has clarified the soldering order of cells.
Step 10

Complete Homemade Panel

In the photo above you can see that an odd number of cells is used to achieve a series and that the series are ending on opposite sides. If you look closely 9 solar cells are used to produce a cell series and 8 series of solar cells are used to produce your panel. Now that you have the wiring figured out we can proceed to put the solar panel together. A link for those instructions are in the resources section.

Comments

pooleuk said

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on 10/13/2009 Beware, some vendors over-sell by quoting W as Imax*Vmax, real cells do not give Imax and Vmax at the same time, so a figure of 1.75W is likely to be purely notional. Expect a usable output of more like 0.8W at around 0.35V/cell. This means you typically need 36 cells to charge a 12V battery at peak efficiency per cell, not 24 as the open circuit voltage (eg 0.55V) per cell would suggest. Also, you should protect the cells, eg by installing within a double glazed sealed unit. This will reduce power to around 0.7W per cell - and you may lose a bit more in your wiring.

conora2b said

on 9/18/2009 this is a really great guide but im kind off stuck on my own project

I am running a 24V battery bank for my wind turbine and want to add solar to the same bank so far i have bought 110 3"x6" solar cells rated as follows,
0.5v x 3.5a = 1.75w each

this is what im thinking off so far please correct me if im wrong in any part of it
to get 24V i need 48 cells in series and 2 sets in parallel (94 cells in total 24V + 7a) to make the most of my cells im thinking of building a 26.5V panel (104 cells in total 26.5V+7a)

is this the right way to go about it or should i lower the volts and increase the amps going to my battery bank and if so will it still store a a 24 v charge?