It takes a little skill and practice to harvest components from pre-owned or broken solar panels. Yet it is not so difficult that you cannot manage it with basic DIY skills.

You have to free the photovoltaic cells from the base it’s mounted on. After you have done this, check the solar cells for loose connections, broken panels, condensation and damaged diodes. Common problems such as these can potentially cause your solar panels to break down shortly after installation.

If the joints between solar cells are broken or loose, you have to re-solder them. Malfunctioned diodes can be replaced with new ones from your local component store. And if you see broken photovoltaic cells, you will have to source for a similar component to replace it — this can be challenging. Yet you can still make do with the broken cell in case your efforts to replace the broken solar cell fail. There will be reduced power output as a result, but this is not a grave concern.

The array of solar cells is usually mounted on a piece of masonite or acrylic (substrate) board before it is placed into a new solar panel frame. You can discard this substrate after a few years if you intend to replace the solar cells with fresh, new ones.

Using pre-owned solar panels to build DIY solar panels has its pros and cons. The most obvious advantage is the price. Used solar panels can be very cheap and some kind contractors may even give them to you without asking for a single cent. You are also less worried about breaking expensive photovoltaic panels while building your project.

On the other hand, a used solar panel’s lifespan may be significantly shorter. Their power output will also be a little lower compared to when it was new. A loose connection or a fault may hide itself somewhere that escapes your attention. As you build your DIY solar panel, trouble may spring up from these areas. However this can be managed if you’re careful in checking for potential failures.

Overall, harvesting parts from a used solar panels proof to be the best money saving method to build DIY solar panels. The only downside is the additional effort you have to put in. Yet as DIY hobbyists, we tend to take joy in such labor.

Continue Reading:

1. How To Build A Personal DIY Solar Power System With Less Than $99
2. Step-By-Step Guide To Build A 12V Solar Panel
3. How To Find Used Solar Panels

You must use the proper wire size so electricity from your solar panels can reach its destination (like your battery bank) without severe loss of power.

A simple calculation will help you decide what wire size to use. A common standard for wire size is based on the AWG (American Wire Gauge).

Step 1: Decide on the voltage for your solar power system: 12, 24, or 48 volts

With lower voltages, you’ll require thicker wires. Recall:

Power = Current x Voltage

The power output remains constant. Therefore when voltage decreases, current increases.

Using thinner wires means you’ll have to spend less on cables. However this is not a great consideration if you do not have long cables to manage.

Do note that whatever voltage you decide on, the rest of your equipment (like charge controller and inverter) will also have to follow suit.

Step 2: Determine the maximum current (in Amperes) your solar panels will produce

You can get this figure from your datasheet. If you have built your own solar panel, you can first find out the maximum output current of each solar cell from its datasheet. Then calculate the resultant output current according to how you connect the cells together.

After you have got the maximum current rating for one solar panel, simply multiply it by the number of parallel-connected panels you have in the array.

Note: If you connect the PV panels in series, the voltage adds up. If you connect them in parallel, the current adds up while the voltage remains the same.

For example, if you have two 12-volt PV panels connected in series, the output voltage becomes 24 volts while the output current remains the same. If you connect these two panels (rated at 10 amps each) in parallel, you’ll get a current output of 20 amperes while its output voltage remains at 12 volts.

Step 3: Estimate the length of your cables

Estimate the distance between your solar panels and your battery bank (or wherever you want the cables to run to) in feet. Then add to this figure by another 5% to cater for loops and tiebacks, if needed.

Finally multiply this figure by 2 because one cable will run to the battery bank while the other will run back from the battery bank. (One positive and one negative.)

Step 4: Determine the allowable voltage drop across your cable

Power loss and voltage drops are unavoidable. For your initial calculation, you can simply use 3% as an estimate.

Eventually, you’ll have to use your voltage meter to measure the actual value across your solar panel array output and determine what’s allowable.

Step 5: Use the chart below to find out which wire you should use

First, you have to calculate the VDI value:

VDI = (Current x Distance) / (% Voltage Drop x Voltage)

Then compare this value to the table below to find the type of wire you should use.

For example, I have chosen a 24-volt system that gives me an output of 20 amps. My cables will run a total distance of 100 feet, to and fro. My allowable voltage drop is 3%.

Therefore my calculation will be:

VDI = (20 x 100) / (3 x 24) = 2000 / 72 = 27.8

Referencing the table below, I should be using a 2-gauge wire according to the AWG standard.

Note: Your max operating current must not exceed the max current ratings as stated in the table.

Continue Reading:

1. Sizing Your Solar Energy Panels – Part 2
2. Sizing Your Solar Energy Panels – Part 3
3. Homemade Solar Panels — Common Mistakes to Take Note Of When Building And Installing Photovoltaic (PV) Panels

How To Build Solar Panel

In this part of the “How To Build Solar Panel” series, you’ll learn how to put the different components together. Hopefully you’ve already got an idea what you want to use your solar panel for.

We’ll use a 12V DC automatic door opener as an example…

To power an electrical system that runs on 12VDC, we need a 12V battery. I’d prefer using one of those maintenance-free batteries as compared to troublesome lead-acid types. And in order to charge the 12V battery, we’ll need the solar panel to generate about 18V. (It needs to be at least 5V above the battery voltage)

Connecting the Solar Cells

Each solar cell produces 0.5V. To get 18V, we can join 36 solar cells in series. Assuming the solar cells are of the same quality, a larger solar cell will produce more current and thus more power.

You should always ensure that the power generated by the solar panel is sufficient to charge your battery. Otherwise you may have to join more cells in parallel.

If you want to connect the solar panel directly to your appliance, you can simply make-do with 12V output from the solar panel. This is however not advisable for most applications…unless you need your appliance to work only when the sun is out.

Constructing the Solar Panel Frame

Next, we have to create a shallow box (as solar panel frame) for the solar cells to sit in. The borders of the box should be about ¾” wide by ¾” high. If this too high, it will cast a shadow on the cells as the sun comes in from the side. If it is too low, it doesn’t allow sufficient clearance for the solar cells.

Before you screw the pieces of plywood together, you can first hold them together by super glue so they’ll stay in place as you turn in the screws.

Putting the Array of Solar Cells Into The Solar Panel Frame

To get the solar cells into the solar panel frame, glue the array of solar cells onto a thin, rigid backing before placing it into the “box”. An example of this thin, rigid backing is a Masonite board.

We should give the rigid backing a few coats of paint before pasting the cells on. We must also apply a few coats of paint to the panel frame and dry it thoroughly before putting in the array of solar cells.

Connecting the Diode

Connect the diode at the power output of the solar panel. You should locate this inside the solar panel and hold it down using some silicone caulk so it won’t move about.

Placing the Plexiglass Cover

Before covering the solar panel with the plexiglass cover, test again to see that you’ve got the correct voltage and power output. Then carefully drill the holes (for the screws) at the border of the plexiglass.

Take care to apply moderate, consistent pressure while drilling so that the plexiglass won’t crack. Also remember to countersink the hole so that you can flush the screws with the surface, if necessary.

Attaching the Jones Plug and Battery

At the end of the wire that dangles out of the solar panel, attach the (male) Jones plug by soldering them on. Also solder the female Jones plug to the battery terminals according to their polarity.

Using a connector like a Jones plug makes it convenient for you to disconnect the solar panel from the battery if you need to.

And after hooking up the parts in the above manner, you’ve made for yourself a complete solar power generator that can power up your electrical gadgets — anything that runs on 12V.

In the third and final part of the “How To Build Solar Panel” series, you’ll discover how to “tweak” your solar panel system. You’ll inevitably end up with a world-class DIY solar panel running on steroids!

Continue Reading:

1. How To Build Solar Panel (Part 1 of 3)
2. How To Build Solar Panel (Part 3 of 3)
3. Step-By-Step Guide To Build A 12V Solar Panel

12V Solar Panel

It is easy to build a 12V solar panel if you know how. This step-by-step guide is designed to teach you if you want to build one but are clueless on how to start.

This article also illustrates the sequence to building a 12V solar panel so you’ll have the least trouble.

After reading the 5 steps, I’m confident no matter how confused you are, you’ll be able to move along to begin designing your first photovoltaic panel:

Step 1 – Source for solar cells.

There are a total of 3 ways you can get a solar (photovoltaic) cell — you can buy them, you can salvage used or broken solar cells or you can even make them.

If you intend to use your solar panels for long, I recommend you buy them. Although they’re more expensive, they yield more power and can last longer. Thus you won’t need to make another solar panel a few years down the road.

If you intend to make a solar panel just for fun, you can join pieces of used or broken solar cells to make up a complete solar panel. They won’t be the most professional looking photovoltaic panels around, but who cares, they’re just for fun!

And if you feel more adventurous, you can even make your own solar panel by heating up copper plates to form cuprous oxide, which is a form of semiconductor by itself. These homemade solar cells are inefficient at best and only produce microwatts of power per cell. But if you’re just having some fun are feeling adventurous, why not?

Step 2 – Soldering the solar cells

To form a 12V supply, we have to solder the photovoltaic cells in series so they add up to 12V collectively. While many solar cells are rated at 0.5V each, you’ll have to check its specification before buying and using them. Some may not rated at 0.5V.

With 24 solar cells connected in series, we can easily make an array of solar cells that produce 12V supply.

However voltage is only part of the equation. We also have to consider the current output of the solar cells. With the correct voltage and sufficient current, we’ll have enough power to drive the application of your choice.

Step 3 – Pasting solar cells onto a substrate

After soldering the solar cells, you can prepare to paste them onto a substrate. Many hobbyists prefer to use silicone caulk to do this. However you’ll need to employ the correct technique to paste the solar cells using silicone caulk. Otherwise the cells may crack just after a short period of use.

Step 4 – Put the array of solar cells with a protective box

After the substrate is done, you’ll have to make a box to contain the substrate. This can be made of wood, plastic or metal. Each has its unique advantages and disadvantages.

The protective box is done last. This is because you can then be flexible to alter your solar panel design if you need to add more solar cells to the setup. This will free you from some worrying.

After the box is completed, you can hold down the substrate in the protective box using blobs of silicone caulk.

Step 5 — Cover the solar panel box

Finally, you’ll have to cover the box with a transparent plastic or glass. This will keep precipitation and dew from destroying your solar cells and metallic joints. Many hobbyists choose plexiglass because it’s not as fragile as glass. The choice is entirely up to you.

After completing these 5 steps, your solar panel is ready to produce electricity for you.

Continue Reading:

1. How To Build Solar Panel (Part 1 of 3)
2. How To Build Solar Panel (Part 2 of 3)
3. Used Solar Panels – How To Use Them To Build Cheap DIY Solar Panels

Wiring up all the solar cells in your solar panel takes about an hour or two. But if your solar panel is small and you are skillful, you can complete the task well within an hour.

Solar Cell

You’ll get better with practice.

Here is a list of things you’ll need:

1. Solar cells
2. Soldering iron & solder
3. Rosin flux pen
4. Silicon Caulk
5. 2 gauge copper wire

There are different types of solar cells available in the market. You will either see clear metallic lines or metal squares at the back of the solar cells. Both of these will work just fine.

What You'll Need...

When choosing solar cells, you have to make sure they are consistent. Which means you must use the same type of solar cells throughout the entire solar panel. This will keep things organized and make calculations easy.

Broken solar cells work fine too. But if it’s your first time building your own solar panels or if you want to generate serious power, avoid them. Stick to new or used (undamaged) solar cells.

Before you line up your solar cells, you must know how you’re going to solder them – in series or in parallel. You will have to orientate and organize the solar cells within your solar panel frame before soldering in order to avoid mistakes.

Solar cells connected in series cause the resultant voltage to add up. Connecting them in parallel results in a higher current. You must make sure your solar cells are connected so you end up with an array with your desired peak DC voltage and current.

When soldering copper wires to your solar cells, use the flux pen to help you achieve a good joint between the solar cell and the copper wire. This is especially important if the metallic surface is slightly oxidized.

After soldering all the solar cells together, test the voltage and current output.

Next, put a blob of silicon caulk at the back of each solar cell. Then attach them to the substrate and wait for the silicon caulk to dry completely before covering up the solar panel frame.

Notes:

• Many solar cells produce 0.5 volts (open-circuit) when exposed to sunlight. A 100 cm² silicon cell reaches a maximum current intensity of approximately 2 Amperes when radiated by 1,000 W/m².

• Some solar cells come with connection ribbons already attached. Thus you will have to solder them differently and ensure the leads do not touch one another to cause a short circuit.

• Heat from the soldering iron can cause burns and possible damage to solar cells. So rest it on the solar cell for only as long as necessary to make a good joint.

Continue Reading:

1. How To Build Solar Panel (Part 2 of 3)
2. Step-By-Step Guide To Build A 12V Solar Panel
3. Used Solar Panels – How To Use Them To Build Cheap DIY Solar Panels