How to Build a 12Volt Portable Generator

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Powerful electrical generators work to send electrical power across power grid distributions throughout neighborhoods and cities. The same way these generators harness their power, you can make your own electrical generator which you can then use to power other items like batteries or circuits.

You can even build your own 12 V (12 volt) circuit as a battery backup in case your house lighting or other electronic devices lose power. To build one, you need automotive alternators and batteries with 12 V lights.

Building a 12 V Generator

Alternators and generators both use electromagnetic induction to generate power. Generators in cars and other vehicles use a pulley connected to a drive shaft such that the pulley coils wire around in a circular direction to create a magnetic field that produces a current.

The coil, called an armature, creates electricity that the vehicle uses, and while generators produce DC power, alternators on the other hand produce AC power using a rotating magnet instead of a rotating coil. You can even use your vehicle's alternator for generator power alongside extra wires such as jumper cables and other devices that may be necessary.

Look for older designs of alternators that have been used in vehicles or a gas powered engine from a lawn mower. These alternators are generally built with internal regulators to change the firing rate for more customization and easier installation. Use a socket and ratchet or a wrench to remove the alternator from the vehicle or mower. (Keep the retaining bolts and other parts you remove if you plan on placing the alternator back!)

Then, connect the device you want to power to the 12 V battery. Use the largest terminal that you find on the alternator as the positive end of the battery. The negative terminal depends on the design of the alternator so make sure you can run tests to figure out which end is negative. If you find only two terminals on the automobile's alternator, it typically has a regulator built into it for processing the voltage signal.

The circuit you create should energize the regulator when you plug it into the circuit. Three-terminal alternator setups usually mean you have to use an external regulator to connect the alternator to the regulator and connect the regulator to the battery itself. After you have the circuit set up, you can bolt the alternator.

Homemade Battery Charger From Alternator

If you want to, you can bolt the alternator down to another surface so that it remains securely in place by re-using the bolts or using your own bolts. Add a pulley to the shaft of the gas motor so that the alternator drives through a belt to generate power or you can use the pulley that was built-in with the alternator. If there is a split rush bushing the alternators uses to fill space, you need to tap on the bushing to let it fit back into the bracket. You can move the bushing more easily with drift punches or a long bolt with a nut in one end of it.

Make sure your alternator setup is clean. If the terminals of the alternator show signs of corrosion, you may experience large drops in voltage. This is what causes alternators in cars to fail in many cases. To clean an alternator, use a mixture with a dilute amount of shelf degreaser in water, and apply the liquid with a cloth or spray.

Let the cleaner soak on the alternator material for about five minutes, and then use a soft, short-bristled brush to clean areas that are dirty due to corrosion. Don't use petroleum-based degreasers, compressed air or a pressure washer. Make sure not to spray directly into the air inlet openings of the alternator.

If you want a homemade wind generator using a car alternator setup, you can place the alternator and the setup alongside it in a windy area or apply a large amount of wind to it to see if it generates power. Other possible sources of energy include a paddle that you can connect to the alternator so you can harness the power of moving water. Connect a battery charger and batteries to it to see if the batteries recharge. Use a multimeter or voltmeter to measure the voltage to see if you can achieve 12 volts.

Convert Car Alternator to Wind Generator

Aside from a homemade battery charger from an alternator setup, you can use the generator to power refrigerators, stoves or other electronic appliances in your house. Though it won't be a free energy alternator system as you'll have to use a source of power, you can measure how much voltage there is in these processes using a multimeter or voltmeter. To create a wind generator, in addition, you should apply the car alternator in a specific way.

You can use a fan clutch from a vehicle as a wind generator for your alternator-generator setup. Attach the blades of the fan clutch to the alternator itself so that the alternator's fan lines up with the shaft of the alternator. Check to ensure the alternator-generator's built-in wires and additional plugins are on the bottom of the generator.

You can generally accomplish this step using a 5/8-inch-by-3-inch washer that are about 3/16 inch thick, an electric drill, a 1/4-inch thread tap, a drill bit and four sets of 1/4-inch-by-1-1/2-inch to 2-1/2-inch bolts, nuts and lock washers.

The blades for the wind generator are repurposed from a vehicle fan clutch. To attach the blades to the alternator, you can weld the fan clutch hub directly to the alternator hub – just make certain the fan is perfectly in line with the alternator shaft. Also, make sure the alternator’s built-in wire plug-ins are located on what will be the bottom of the generator. If you don’t have access to a welder, you can connect the fan clutch to the alternator using the following materials:

If you connect a wind turbine engine to a car alternator, you need to make sure the setup can withstand the strength of the winds themselves. Bolting the alternator down to a secure piece of metal or other material to keep it stable can make sure it works efficiently and effectively. If you need to take the parts of the alternator setup apart later, make sure you're able to do so with screws and bolts you use to fasten the alternator-generator down.

Using the Alternator-Generator System

You can use the parts and steps of this method to create other forms of generators and power sources for other purposes such as entire houses, electric-powered boats or other uses in which you don't have power immediately available to you.

You can experiment with a variety of alternator-like power sources such as lawn mower engines, car batteries or other generators that make use of engine pulleys to power other objects. Make sure you have the wrenches, drills, belts, screwdrivers, ratchets and other equipment necessary.

The 12 V system is common to other sources of electrical power. Solar and wind power sources can create 12-volt systems for off-grid cabins that you can manipulate with charge controllers. This homemade wind generator using a car alternator setup and other alternator-generator systems can save you money by reusing energy through these methods.

References

About the Author

S. Hussain Ather is a Master's student in Science Communications the University of California, Santa Cruz. After studying physics and philosophy as an undergraduate at Indiana University-Bloomington, he worked as a scientist at the National Institutes of Health for two years. He primarily performs research in and write about neuroscience and philosophy, however, his interests span ethics, policy, and other areas relevant to science.

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