How to Build a Small Wind Turbine from Household Materials

Building a small wind turbine from household materials can be a fun and educational project. With some common items and basic skills, you can generate clean electricity from wind power right at home. Here is a step-by-step guide to building your own small wind turbine on a budget.

Materials Needed

Blades

Plywood sheets or corrugated plastic - to form the blade shapes. 3-4 sheets for a 3 blade turbine.
Wood glue - to laminate the blade layers together.
Paint - to protect the blades. Spray paint works best.

Generator

An alternator from an old car or motorcycle - to generate the electricity. Needs to be rated for at least 300 Watts.
Magnets, wire and other parts to build coils if you are winding your own alternator.

Frame

Metal pipe or tubes - for the tower and generator mounting. Galvanized steel or aluminum work well.
Ball bearings - to allow the blades to rotate freely on the frame. Need a size to fit the pipe.
Bolts, nuts and washers - to assemble the frame pieces. Stainless steel is ideal.

Other Parts

12V car battery - to store power generated.
Charge controller - manages power from turbine to battery. Prevents overcharging.
Inverter - converts 12V DC to standard 120V AC power for appliances.
Electrical wire - for connections. 10-12 AWG size recommended.
Wood/metal for housing - to protect components from weather.

Constructing the Wind Turbine Blades

The most complex part is constructing the blade shapes. The ideal blade cross section is an airfoil shape, curved on one side and flat on the other. This shape creates lift as the wind passes over the curved surface, causing the turbine to spin.

There are a few options for building the airfoil blade shapes:

Use a table saw to cut the shape out of wood. Glue layers of plywood together.
Cut sections from corrugated plastic sheets and laminate them together. The corrugations help form the airfoil curve.
Use a jigsaw or handsaw to cut the airfoil shape from wood. More time consuming but avoids power tools.

Cut out three sets of blades that are identically shaped. Make them about 1.5-2 feet long each. Use wood glue to laminate at least two layers together for each blade to achieve sufficient stiffness. The layers must be aligned precisely along the length of the blade.

Once the glue dries, sand and paint the blades for protection from the elements. Use brightly colored spray paint for appearance and visibility. Mask off areas before painting if desired.

Assembling the Turbine Frame

The frame holds the blades and connects to the alternator to harness power from their rotation. Here are the steps to assemble the frame:

Cut the metal pipe to form the main tower section and a cross bar that holds the blades. Install flanges on the ends to bolt pieces together.
Get a large ball bearing that fits over the main tower pipe. This will go at the top.
Fabricate or weld triangular metal brackets to mount each blade on the cross bar. Space them evenly 120 degrees apart.
Install another ball bearing in the center of the cross bar so it can rotate freely on the tower pipe.

Place the blades on the end brackets and use bolts to secure them firmly. Now the blade assembly can spin on the bearings.

At the top of the frame, mount the alternator so its central shaft couples to the bearing. This allows the alternating to turn as the blades spin.

Connecting the Electrical Components

Generating usable electricity from the turbine involves properly connecting the alternator, battery, charge controller and inverter.

Wire the alternator output through a rectifier to convert AC to DC power. Then connect to the charge controller.
Run wires from the charge controller to the 12V battery. The controller regulates charging.
Finally, hook up the inverter to convert battery power to 120V AC. The inverter output can run appliances.

Use sufficiently thick wire rated for 20-30 Amps. 10 AWG wire is a good minimum size to avoid losses.

Carefully study the manuals for the charge controller and inverter for detailed wiring instructions. Getting the electrical connections right is crucial for generating usable power.

Creating a Weatherproof Housing

The turbine components need protection from the outdoor elements. Build an enclosure using wood and/or metal sheeting.

Allow for access tocomponents with hinged doors or panels.
Include ventilation holes so air can flow through.
Mount components securely inside on a wood frame.
Weather seal joints and seams. Caulk and flashing tape works well.

Optionally include a braking system to stop the turbine in high winds. One approach is a pivoting air rudder that turns the blades out of the wind.

Position the housing unit on a concrete pad or piers near the battery bank. Then connect output wiring to appliances or grid tie equipment.

Testing and Troubleshooting

Once all components are assembled and connected, test out the wind turbine operation. Start by spinning the blades by hand to verify alternator output and charging. Then monitor performance in actual wind.

Here are some common issues and solutions:

Low output - Adjust blade pitch or orientation. Ensure tight electrical connections.
No output - Check alternator wiring and rectifier. Inspect bearings and shaft coupling.
Battery not charging - Verify charge controller connections and settings.
Blades vibrating - Balance blades, tighten fasteners, adjust blade angles.

With refined adjustments and alignments, your homemade wind turbine can provide clean renewable energy for years to come.

Conclusion

Building a small wind turbine from scratch takes some mechanical skill and electrical knowledge but can be executed with common tools and materials. Constructing airfoil shaped blades, mounting them on a sturdy frame, connecting the alternator and hooking it all up to a battery bank results in a functioning turbine generating free electricity from the wind. Pay close attention to blade angles, bearings, alignments and wiring connections to get it running properly. Then sit back and harness the wind while lowering your electric bill.