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Homemade Wind Turbine in 5 Easy Steps

Posted by Conor Downes on July 10, 2019
Homemade Wind Turbine in 5 Easy Steps
Learn how to build a backyard wind turbine in 5 easy steps.

So, you want to build a backyard wind turbine and save hundreds every year? Well, you’ve come to the right place. In this post, you will learn how to construct a backyard wind turbine from scratch. Similarly sized commercial wind turbines will set you back a couple of hundred dollars, but with a little effort, you can save yourself so money and because you’ve constructed it yourself you’ll understand the inner workings of a wind turbine in the process. Check out our page Renewable Energy Methods for a downloadable eBook version of this post. Plus loads more free resources on the site!

This post will reduce the project down to just five systems. If attacked one at a time, the project won’t seem too difficult. Outlined in this guide is how you can build and assemble the blades, the generator, the hub and tower, the charge controller and the battery pack systems. Each system’s technical background is explained and then how you can build your own one is explained. 

1. Blades

What is the first thing you notice when you look at a wind turbine? The blades, right? Well, that’s exactly where we’re going to start. There are a number of different orientations of wind turbines we have to consider, so let’s discuss them before we narrow it down to exactly what design would be best for what you need.  

First, let’s talk about the axis. There are two types of designs for wind turbines, the horizontal axis wind turbine (HAWT) and the vertical axis wind turbine (VAWT). A horizontal axis wind turbine means the main axis of the turbine is held in the air parallel to the ground and the blades rotate perpendicular to the ground, shown in the picture below. This 3-blade fan-like design that we all know and love dominate the wind turbine industry and can be seen dotted all over the world in wind farms. Many experts believe it to be the best design choice as it can produce more electricity from a given amount of wind.

This means a lot in large-scale operations where constant energy production is crucial, so it easy to see why they dominate the wind energy industry. However, in smaller applications such as backyard wind turbines a vertical axis wind turbine could prove more efficient.

A VAWT design can be a good option for a small-scale project. It has a few advantages over the more common design: it is a sturdier option in turbulent wind conditions, it can generate power from the wind in a 360-degree sweep radius as opposed to whatever direction the turbine is facing, this leads many experts to believe the VAWT is a more efficient design overall as it can generate more electricity in variable wind conditions where the wind isn’t blowing consistently.

This aerofoil design can easily be created from a sheet a hardwood of light steel if you have access to a workshop and the proper cutting tools. However, for those of us who don’t a simple trick is to use some PVC pipe. This is the pipe you can see used commonly for underground water work and sewage piping. You can easily go to your local hardware store and pick up some meter-long off cuts of this type of pipe and if you’re lucky it won’t be worth their time charging you, so it’ll be free! Now all you have to do is cut the pipe in half and then into quarters using a hand saw and you have the perfect lightweight, strong and durable aerofoil blades.

2. Generator

The generator is one of the most important parts of a wind turbine. It’s the component that converts wind into useful electricity. So how does it work? Let’s break it down to a few simple components. So, to start off a generator is made up of a few coils of copper wire rotating around a strong magnet. The magnetic field created by the magnets causes the electrons in the copper wire to move and then begin to flow. Hence, we have an electric current in the wires and that is basically what electricity is, the flow of electrons through a conductor (here it’s the copper wire). How do we rotate the coils of copper? Well, that’s where the wind comes in.

Now you can create your own simple generator, or you can buy one from one of the numerous online sites selling them cheaply (eBay, Amazon, Alibaba). To build your own you’ll need a couple of lengths of copper wire which you can purchase at your local hardware store and some strong magnets. Mount the magnets to a cylindrical tube. This can be as simple a plastic bottle, but for the sake of strength and longevity, you should consider a steel or wooden vessel would be better. The copper wire should be wound around a rod or a disk with a shaft at the end where the turbine blade hub can be mounted. Ensure your design incorporates a way for the blade hub of the turbine blades to be attached to the shaft of the coils of wires so it can be rotated by the wind.  

And that is pretty much if you have just created an electricity generator. Once the coils of wire and magnets are mounted in your chosen orientation a simple twist of mounted wires will generate clean renewable electricity for you. The voltage output of your design can be measured using a multimeter to ensure it is working correctly.

If you opt to buy one online there are a couple of things you should know first. Permanent magnet DC motors work as generators, however, they weren't designed to be generators, so they aren't great as generators. When using a motor as a generator, the motor must be driven far faster than their rated speed to produce anything near their rated voltage. This is the maximum voltage the generator can output. You want your turbine to be operating in or around this value, so it is working efficiently. What you are looking for is a motor that is rated for high DC voltage, low revolutions per minute (rpm) and high for current. Try to keep away from low voltage and high rpm motors. You want a motor that will put out over 12 Volts at a low rpm, and a useful level of the current so it can easily trickle feed a 24 Volt battery. A motor rated for around 300 rpm at 30 Volts when used as a generator, could be expected to produce 12 Volts or above at some reasonably low rpm. On the other hand, a motor rated at a couple of thousand RPMs and outputs 24 Volts won't produce 12 Volts as a generator until it is spinning many thousands of rpm, which is way too fast for a wind turbine and may cause damage to it, its surroundings, or even you. So, try to shop for motors using the information above.

3. Hub and Tower

A hub is only needed for a vertical axis wind turbine. If you opt for the horizontal axis wind turbine then simply mounting the blades to the generator hub is enough. The hub (or the main stand) of your wind turbine is going to be the easiest part of the build. Although this doesn’t mean it isn’t a crucial component. You will want to get this right for the sake of the structural integrity of your wind turbine. It can be as basic as a plank of wood, but you will ensure it is a hardwood that’s appropriately treated so it can survive outdoors in wind and rain for a few years. Your hub needs to hold 3 main components; the generator (which at this point should have the blades mounted to it), a tail fin and a counterweight. Holding the generator is obvious but what do the tail fin and counterweight do? With the fin mounted at the opposite end of the hub to the generator, this ensures that the turbine always points the blades towards the wind. The counterweight will stop your blades toppling the turbine over and ensures the hub of your turbine stays upright. The counted weight should be ideally mounted underneath the fin but can also be mounted either side of the fin which can be easier.

The hub body is a simple wooden block with a thin sheet of plywood bracketed to the hub as a fin. The counterweight is a plastic bottle filled with sand and strapped with cable ties to the main hub block. This isn’t an ideal design, but it is simple, cost effective and easy to attach so it is one worth considering. You can easily improve this design by sourcing some lead counterweights and bolting them to the bub. Or create your hub out of steel and if you have access to one weld some heavy steel to the back end. Again, the final design of your wind turbine is up to you and what is shown here is just an outline.

Now your turbine needs to be put into the air above any trees or buildings potentially blocking it from direct wind. For this, you will need a tower to get your turbine up in the air and harnessing wind power efficiently. Your towner should be about 9 feet or about 3 meters in the air to clear most small buildings and surrounding trees. Another tip is to put the turbine out in the open away from trees and buildings to avoid this problem altogether.  The tower should be made out of steel because if this component fails it could cause damage to the turbine or the surrounding area, so you want to avoid this. You can construct the towner from steel rod or pipe which can be easily found at your local hardware store and you should try the free offcut tip again to keep the cost of your turbine down. If not, you can cheaply buy a couple of lengths from the store and with a few welded joints, so you can make the rods long enough for the tower. Again, if you don’t have access to a welder a few drilled holes and some bolts will be enough to attach the rods together to the desired length. Another tip for getting the tower to the desired height without welding or bolting is to source some lengths of steel rod with pushbutton inserts. You know the ones, where the rod is narrow at one end and wider at the other, so they can slide easily into each other and be realised with the push button. These can easily be assembled and for a great tower for your wind turbine tower.

Finally, your hub has to be attached to the tower and the tower has to be erected. The hub needs to swivel so the fin can direct the blades in the direction of the wind as discussed above. To achieve this design, you can simple attached a bolt whose diameter is smaller than that of the rod, so it can slide right in as shown in Figure 7. Ensure the bolt is about a foot or 0.3 meters long for a sturdy design. The hub should now freely swivel around on top of the tower. To allow the hub to rotate freely when the wind changes direction to add some lubricant of oil to the bolt so there is no wind energy lost to friction. To keep the tower upright attached a wide base to the bottom rod. You can use the bolt method again or weld it to a metal plate. Then just anchor the tower to the ground using wire or rope and peg them to the ground and your hub and tower should be good to go and strong enough to brave the wildest storms.

4. Charge Controller 

Whether you build your own or buy one, you will need some sort of controller for your wind turbine. The general principle behind the controller is that it monitors the voltage of your battery system and either sends power from the turbine into the batteries to recharge them or dumps the power from the turbine into a secondary load if the batteries are fully charged. This prevents over-charging and destroying the batteries.

Now that you have most of the mechanical parts built, you can look at the electrical components of your wind turbine. A wind power generation system generally consists of the following subsystems; wind turbine, batteries to store power produced by the turbine, a blocking diode to prevent power from the batteries being wasted or inadvertently spinning the generator, a dummy load to dump power from the turbine into when the batteries are fully charged, and a charge controller to run everything.

There are lots of charge controllers available on Amazon and eBay for solar and wind power systems that you can buy if you want to avoid the hassle of building a fairly complex electrical system. But, if you like a challenge and consider yourself thrifty and are looking to save a few bucks below we will briefly look at what it takes to build your own. Again, this is a general outline and a quick google search will bring up hundreds of schematics you can follow so your design can always do things differently. There are also a number of websites you can check out that go into the detail of designing your own charge controller.

The charge controller consists of several components which can all be mounted to a piece of plywood and you can use the schematic in Figure 8 as a reference for the layout. You will need a heat sink with blocking diodes. This allows the current to flow in one direction only so power from the batteries does not start powering the generator. The diodes are connected to dummy loads which dissipate any excess electricity to avoid overcharge damage being caused to the batteries once they are fully charged. The dummy loads can consist of high voltage resistors. You could also divert excess power from the turbine into something more useful like a water heater or a second battery bank. The main fuse for the wind turbine made of about a 40 Amp automotive relay connects everything together and will also send the power generated by your turbine either to the batteries or to the dummy load.

Your wind turbine is connected to the controller by lines that run from the generator, then run from the controller to the battery system which we will discuss later. These lines should be insulated copper wire and you can use an old extension cable to run a wire from generator positive and negative terminals to the charge controller terminals.

For safety reasons connect the battery first, then connect the wind turbine. If you connect the wind turbine first, the wild voltage swings coming from the turbine won't be smoothed out by the load of the battery and could damage the system. So always connect to the battery first, then connect the wind turbine. Also, make sure you disconnect the wind turbine first when taking the system apart. Disconnect the batteries last. 

5. Battery

The last system we will look at is the battery system. This is the system that will store all your clean energy produced by the wind turbine and convert it into useful electricity you can use. Making the system is pretty simple, all you must do is source the batteries you want and connect them to each other, connect one end to your charge controller and on the other end a power inverter to convert your stored energy into useable electricity, and there you have it. This section will help you with the more difficult part like what type of battery to use, what voltage and capacity to use and what orientations to arrange them in.

Let’s start with what type of battery you should use. The different types of chemical energy storage you can consider are lead-acid, lithium-ion, hydrogen and flow batteries. Here’s a brief overview of each of the different technologies/

Lithium-Ion

Lithium-ion batteries are one of the most popular energy storage options today with them being increasingly used in mobile electronic devices and electric vehicles. They have a high round-trip efficiency of about 99%, an energy density in the range of 250 Wh/kg and capable of withstanding just under 2000 cycles before fading. However, the popularity of the Lithium Ion battery has led to advances in technology which now has it outperforming the other types of battery with respect to energy density, power density and round-trip efficiency. 

Lithium-ion batteries are however one of the most expensive types of batteries being nearly six times as expensive as lead so if you choose this option your investment cost will be big. The higher costs are associated with the materials used, manufacturing process and auxiliary systems required for their operation. There are also concerns about the disposal of spent lithium batteries which can result in the release of toxic material so if you’re trying to be environmentally conscious with your project this is something to consider.

Lead-Acid

The lead-acid battery is the oldest, cheapest and most mature form of chemical energy storage. Deep-cycle lead-acid batteries are ideal for small-cycle renewable energy integration applications; these batteries can be discharged repeatedly by as much as 80% of their capacity and hence are suited for grid-connected systems where users sell power back to the grid through net metering. Coupled with low investment costs and the relatively low maintenance of the battery they would one of the most suitable batteries for small-scale wind energy projects.

Limited cycle life and poor performance at low and high ambient temperatures are a pitfall of this technology. But it is the cheapest and most widely available battery and can be bought in your local motor factor store. Like lithium-ion batteries concerns over the lead acids environmentally unfriendly and toxic materials make it a hazardous product to dispose of when spent.

Hydrogen Energy Storage

A hydrogen fuel cell uses electrolysis of water process to produce hydrogen and oxygen. Excess electricity from a power generation source supplies the electrolyser (reverse fuel cell), splitting water into H2 and O2. The H2 can then be stored in compressed gas or liquid form. When electricity is needed, H2 is supplied to a fuel cell which converts the hydrogen and oxygen back to electricity and water, or directly to a generator or gas turbine as a combustible fuel.  

Hydrogen-based energy storage systems are receiving increasing attention today, particularly in relation to their integration with renewable power sources. Hydrogen fuel cells have several advantages, including high energy density, large storage capacity, the fact that surplus hydrogen off-gas can be used to supply the transport energy demands and being environmentally safe. It is still a costly method of energy storage, has one of the lowest round-trip efficiency ranges of 20-50% and would be hard to source for a small-scale energy storage system, but it is one you can consider and make use of if you can source them.

Flow Batteries

Flow batteries can be described as ‘halfway between a battery and a fuel cell’. This energy storage technology can have round-trip efficiencies of 80% and lifetimes of up to 25 years. Their ability to fully cycle and stay at 0% state of charge (SOC) makes them suitable for wind energy storage applications where the battery must start each day empty and fill up depending upon the load and weather. This type of battery consists of two electrolyte reservoirs from which the electrolytes are circulated (by pumps) through an electrochemical cell comprising a cathode, an anode and a membrane separator. The chemical energy is converted to electricity in the electrochemical cell when the two electrolytes flow through. Both the electrolytes are stored separately in large storage tanks outside the electrochemical cell. 

Flow batteries boast high power, long duration, power rating and the energy rating is decoupled, electrolytes can be replaced easily, fast response and can go from charge to discharge modes in less than 1 second. However, low efficiencies and high cost make this technology more suitable for large-scale projects with advancements in the technology looking extensively to replace traditional lead-acid batteries. If you can source a cheap one, it is defiantly a battery worth looking into.

Once you’ve decided on a battery technology you want the next to thing to look at is what voltage and amperage to get. The most easily sourced battery sizes are 12V and 24V which are perfect for your single backyard wind turbine project. Now let’s consider the amperage. The batteries can come with a range of capacities which is measured in amp-hours. Say if you get a battery that is 12 volts and has a capacity of 10 amp-hours then you’d probably want to connect 10 together in parallel to up the storage capacity to 100 amp-hour which would be perfect for your small-scale project. Obviously, the higher storage capacity of your system the more energy you will readily have on hand so there really should be no cap on the storage capacity of your system.  

The batteries should be connected positive to positive and negative to negative using jumper cables that can be purchased online or in hardware stores. The last positive and negative output in the series must be connected to the inverter to turn the DC voltage into useable AC power. Make sure you source an inverter with a plug adapter output, so you can run an extension cable with a multi-plug adapter away from the system to where you want to use it. Inverters can be quite expensive and will most likely be the most expensive item for this project. But you want a good quality inverter for the safety of yourself and the products you’re using your clean energy to power.

Costs

So, let’s roughly break down the cost of this homemade wind turbine. Obviously, these are estimates and a quick google search could offer up cheaper items than the ones listed here. You could easily source some of these items around your house too which will help you save a few bucks here and there like, for example, using an old car battery could save you some money provided it is not completely dead. Scrap metal and wood can also be used to build your homemade wind turbine more cost-effective. The table below roughly breaks down the costs involved and where you can source them from. 

 

Table 1: Table of the cost involved for a homemade wind turbine

Part

Source

Cost

Generator

Amazon

$20.00

Blade Hub Fittings

Home Store

$15.00

Pipe for blades

Home Store

$10.00

Misc. Hardware

Home Store

$5.00

Wood & Aluminium

Home Store

$50.00

Extension and Jumper Cable

Old extension cord plus new cables

$30.00

Rope & Pegs

Home Store

$20.00

Charge Controller

Amazon

$20.00

Lead Acid Battery

Motor Factors

$40.00

Inverter

Amazon

$70.00

Total

 

$280.00

The costs do add up a bit for a small project, but this isn’t bad when you compare it to a commercially made small backyard wind turbine with similar power output. Add in the commercially made charge controller and a commercially made tower needed to complete the job and this adds up to less than $750-$1000 in total. 

So, you could be saving yourself over $750 by building your own, not to mention the savings from the reduction in your electricity bill which even over the course of one year will start adding up.

Conclusion

So, there it is you now have all the tools and knowledge to build your very own homemade backyard wind turbine and harness all the free and clean energy you want. Now go out there save the planet and save yourself some money and welcome to the clean energy revolution! Don't forget to check out Renewable Energy Methods for the downloadable eBookand more free resources.

 

 

 

 

 

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