Once your solar panels are up and running, the next obvious requirement is some sort of charge controller, since continuous overcharging will ruin the expensive battery bank.

Charge controllers intended for solar panels work by monitoring the battery voltage, and once it reaches full charge, the controller simply short the solar panel leads together. This doesn’t harm the solar panels but it does waste whatever power they are generating. The energy ends us up heating the transistors in the controller instead.



Simple Charge Controller Circuit

Charge controller

In a typical charge controller for a solar panel, the incoming battery voltage is divided in half by a pair of 3.3K resistors, so the trip points are adjusted to one-half the desired levels. Start at 14 volts for the trip points. The actual trip points will depend on your particular batteries, but a good starting point is 14.5 volts for full charge, and 11.8 volts for discharged. In this case, the trimpots should be adjusted to read 7.25 volts at TP-A and 5.9 volts at TP-B.

You will probably need to monitor your battery voltage through several charge cycles to determine the perfect trip points for your system.



Simple Wiring Diagram Showing the Charge Controller and Batteries.

Wiring diagram for charge controller and batteries

You can easily buy a charge controller or build your own custom made if you know how. Certainly the best option is buy an already built controller as this is a critical part of solar panel energy system.

In our next post we shall discuss the main points on building the battery bank. Until then…

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This is our seventh post on the subject -Build Your Own Home Made Solar Panels-

In this post we shall discuss how to connect the solar cells together.

Let´s dive into it…

You will find little tabs on the back of the cells. Take your soldering iron and heat it up. Touch the tip to the tab and gently feed some solder onto the heated surface of the iron. Just one drop will do. Make sure you do all 4 or 6 of the tabs you find.

Wiring solar cells

The tabs on the back of the cells will form a line, one on top and one on bottom. The top tabs are negative and the bottom tabs are the positive leads.

With the drop of solder on the backs of the tabs gently place a copper wire lead onto the tab and heat it up. The wire will bond to the tab and connect the negative tabs together.

< -- Check the pictures

Wiring solar cells

Use different color wire for negative and positive leads to avoid confusion.

The cells should be stuck down to the plywood base in the pattern you made before and the wires are gently fed through the back of the plywood.

Use enough caulking to secure the cell to the backing. We usually use some sort of silicone because is pliable and lasts long time.

Use each hole for two cells, one facing right and one facing left, so the lead wires will easily thread trough the holes. Be careful not to press too hard on the cells when you are attaching them. We usually use a small piece of wood to place on the cell to press evenly with, avoiding breakage

Do the same for the other tabs.

Solar cells backer

When you have all of the solar cells stuck down on the backing you will need to wire all of the same color wires together.

It is a good idea to make leads long enough to join the ends later. Test fit a couple of cells before you begin.
Remember to connect all of the positives leads together and the entire negative leads together, or your panel will not work properly.

This spaghetti of wires will get connected to a junction box outside of the panel. We put another piece of plywood on the back of this backer piece just to keep out the weather. Remember to coat it with three coats of epoxy too.

All of the same colored leads will be joined together and the positive and negative leads will be connected to just one wire leading to your batteries.

Use the glass to cover the front. You can use aluminum sealer strips that you can screw the glass down with or make your own from wood. Seal up all the edges and leave a drain hole in the bottom of the panel to let any accumulated moisture drain out.

In our next post we will describe How to Connect the Controller.

Make sure you return to this website and please share our post with more interested people.

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First you will need a base to place the solar cells on in order to make a panel. You need enough solar cells (about 80) to layout a fairly large surface area. You will notice that there are two distinct sides to a solar cell.

The front looks kind of a blue color while the back looks very much like the back of a mirror. It is essential that you set up the cells with the blue or upper surface facing toward the sun.

putting solar cells together

Each solar cell will create not much more than one half a volt DC usually. The voltage remains the same. As the size of the cells increase, depending on what you get, the current or amperage will increase.

You can place the solar cells out on the floor before you begin, like a deck of cards. Leave a space between each cell of about one quarter inch. Arrange the cells in rows until you have a shape that is pleasing to you. You want to make the finished panels slightly narrower in the width so they are easier to handle, but you can do as you like.

Once you have the cells laid out in the pattern you want, measure the outside dimensions of the rows. You need to know how big to make the backing board. You will attach the solar panels to this board so you need to know how big it is.

backing board of solar cells

With 80 cells you should end up with a panel that produces approximately 100 watts of power.

You can use some plywood or any kind of strong lumber. The nice thing about the plywood is that you don’t have to join it together. After getting the outside measurements we assess what glass we will have to cover the upper portion of the panel. You can put 2 inch spacers on top with a ventilation space around the panels as well.

The glass will usually need a support in the middle too so leave room for that as well.

Let’s say that the layout of the cells added up to a size of 24 inches wide and 40 inches high including the spaces between the cells. If we wanted a 2 inch spacer in the middle and all the way around the outside to support the glass then our plywood should be cut to 30 inches by 46 inches. In this way we could fit the cells on the plywood and still have support for the glass.

Before you begin to put the cells down on the plywood we first treat the plywood with an epoxy sealer that is designed for UV protection. It sinks right into the wood and protects it long term from the weather.

The holes in the dividers will have the wires from the cells meeting and joining to form the circuitry of the panel. The holes also allow a certain amount of ventilation too. Make sure you put at least 3 coats of the epoxy on everything as it will be exposed to some rough weather at times.

Get any kind of soldering gun with at least 25 watt and use silver bearing solder for soldering purposes, which you will need in the next step.

In our next post: connecting the cells together…

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A Photovoltaic System to Suit Your Particular Power Requirements

Right now you can choose from three main types of panels: Monocrystalline, Polycrystalline and Thin Film or Amorphous.

Monocrystalline Solar Panels

For many years monocrystalline solar modules have been the workhorses of the solar market. Those iridescent blue faced panels you have been seeing on rooftops are probably of this type of panels. For most of you this is the type of solar panels you will build because these types of cells are readily available.

They have distinct rounded individual solar cells visible from all angles stacked in very uniform rows. This type of solar panel is produced from a single silicon ingot or crystal with high manufacturing costs, making them the most expensive solar modules on the market.

They are, however, the most efficient type of solar panel making them the correct choice when space is at a premium.

Monocrystalline cells have a life expectancy far exceeding 25 years, probably over 50 years. The only real problem with this type of cell is it’s fragile nature making it a requirement that it be mounted in a very rigid frame.

Polycrystalline Solar Panels

Polycrystalline modules are manufactured from a block of multi-crystalline silicon. They are usually square and have a varied, almost mosaic-like appearance. Only slightly less efficient than monocrystalline modules they are cheaper to manufacture and thus cost less money.

You can expect the same great lifespan as monocrystalline cells too.

Thin Film Solar Panels

Recently a new product was introduced into the market that could provide some much needed answers for solar power users. Amorphous silicon or thin film technology could make rigid solar panels obsolete if some better research is done.

Thin film solar panels are produced by applying silicon material on glass or stainless steel, or more commonly between two pieces of flexible laminate material.

Solid or rigid thin film panels are in use but flexible laminated thin film panels are more popular. The flexible panels can be applied to any surface and sometimes used as roofing material.

Most customers like the almost seamless blending of solar panels right into their roof top. Saving you the cost of regular shingles or steel roofing, thin film solar panels are a good choice.

These panels are not nearly as efficient at converting light to electricity when compared to mono or polycrystalline solar panels- not nearly by half. You would need twice the space to accommodate their installation.

From a manufacturing standpoint they do absorb light more efficiently though, allowing for a thinner design and less material being used in their manufacture.

The real benefit, because less material is needed, is in the simplified manufacturing process resulting in lowered costs to build. The lower price has pushed thin film panels to the lead in price per watt of output.

The panels may have to be slightly larger, but it costs less for the homeowner for every watt of power production. They are flexible, light and rarely break during shipping. Add in the great price and this makes thin film panels a great choice where space is not a consideration.

They jury is still out on the lifespan of these panels though. Some say they will last just as long as monocrystalline panels, others point to their decreased efficiencies only a couple of years after purchase.
As mentioned earlier, with increased research this could be the answer.

New Technologies

There are many new forms of solar panels out there, from spheral solar to liquid paint on solar panels. All very revolutionary, but all need some time to be properly tested before it becomes a real alternative.

Hello, welcome to these series of posts on how to build home made solar panels.

First you will need a few tools and a comfortable work space. You will be doing some wood work as well as electronic work so a nice comfortable workbench and chair are ideal.

Things you’ll need…

Cordless drill, soldering iron (small pen type), pliers, hammer, caulking gun and miscellaneous nuts and screws

This is a picture of the back of a solar cell, the building blocks of solar panels. Several of these small cells which are about the size of your hand go into the making of a solar panel. Mostly we use monocrystalline solar cells.

Back of solar panel

This picture shows you the component parts of a solar cell. They are small and very fragile until they are mounted.

Solar panel choices

Solar panels are probably the simplest form of renewable energy. There are no moving parts and there are installations in place with only minor maintenance for over 20 years.

How does thes sun make electricity?

Simply put, the cells inside of a solar panel convert the sun’s energy into electricity. Photo Voltaic cells are normally fabricated using special semiconductor materials that allow electrons, which are energized when the material is exposed to sunlight, to be freed from their atoms.

These cells are what you will have to obtain in order to build your own solar panels. Lots of people mistake solar cells for solar panels; just remember, that it takes many small solar cells to make one large solar panel, like putting together lego blocks or piling firewood in your backyard.

Once freed, the electrons can move through the material and carry an electric current. The current flows in one direction (like a battery), and thus the electricity generated is termed direct current (DC).

Just under the surface of a solar panel are small thin pieces of semiconductor material called cells. These cells, usually a series of cells aligned in rows, make up the panel.

The cells that make up the panel are made of silicon in most cases, and are treated with phosphorous or boron. As light strikes the cells it is captured by the semiconductor material. This is known as the photovoltaic effect.

In our next post more about the Photo Voltaic effect. Stay tuned.