A windmill with batteries is a great way to create clean, renewable energy for your home or office. It’s a simple, cost-effective project that can be built by kids and adults with little or no engineering skills.
The windmill was one of the first breakthroughs in medieval technology and is a popular energy source today. Originally, windmills were used to grind grain or pump water but they can also convert the energy in the wind into electricity.
In the modern world, windmills are commonly found in developing countries to charge phones and operate radios and lights. They’re also a fun, hands-on STEM activity that can be done at home or in the classroom.
Build a generator for your windmill
You’ll need a small generator to convert the rotational motion of the turbine into electricity. You can use an old car alternator or a homemade generator made from scrap metal. Alternatively, you can buy a ready-made generator to save time and money.
Choose the right blades for your windmill
You can buy pre-made or DIY wind turbine blades. The type of blades you use and the configuration will affect the performance of your windmill. For example, using an even number of blades can make your windmill more likely to vibrate and shorten its lifespan. Adding more blades increases torque, but it can slow down the speed at which your turbine turns.
The blades on your windmill need to be shaped and sculpted correctly in order to produce enough power. Most windmills have an odd number of blades for stability reasons, but you can choose whatever number is optimal for your location and conditions.
Make sure your windmill’s blades are angled upward and away from obstructions to increase the amount of wind that can reach them. If you don’t do this, the blades may wobble and cause your turbine to spin more slowly.
Mount your windmill to a sturdy pole that’s high above any nearby trees and obstacles. Place the windmill near a source of natural light and in a spot with a steady breeze.
A 12-inch nipple needs to be attached at the back of your bracket to spin your generator around and line up with the direction of the wind. You can cut a fin that’s about 1 foot high and 2 feet long out of old tin siding or roofing with tin snips or a cutting torch — a right-angle-triangle shape works best.
Connect your generator to the nipple and connect your battery, a blocking diode to prevent any power from the generator being wasted spinning the motor/generator, and a secondary load that dumps any power into your battery when it’s fully charged.
Lastly, attach a tail fin to the nipple to keep your generator facing the wind. If you’re using a tail fin made from corrugated metal, it’s a good idea to cut it out of corrugated steel so that it’s horizontal.
Ultimately, you want your windmill to generate enough electricity to run all the devices it’s connected to. This will help to reduce your electric bills and save the planet.