DIY Wind Generator Frequently Asked Questions (FAQ)
Since 2007, I've received a ton of email regarding my wind generator. While I love to respond to each email personally, sometimes I get a little bit behind. So, I'm going to make an attempt to answer my most frequently asked questions on this page. But please still feel free to contact me if there is anything I've left out here, or for any other reason!
How much power will your wind generator produce?
Typically I can get from 150-200 watts from my wind generator at any given time. What does that mean? With this setup, you should be able to power 6 or 7 compact flourescent light bulbs with no problem (as long as the wind is blowing). In addition, most laptops consume on the order of 100 watts, so that would be a suitable application too. However, do not expect to power your hot water heater, refrigerator, or stove with this type of small wind turbine. Those devices consume kilowatts of electricity! Additionally, The power output is heavily based on the location. You need a location that gets a decent yearly average wind speed to really get much use out of it. It would be best to put it in a place without many trees and higher than 5 meters (15 ft) off of the ground.
How much will this wind generator lower my monthly bills?
That depends on how much electricty you are consuming, but likely not by much. According to the U.S. Department of Energy, the average American household pays 12 cents per kilowatt hour for electricity. With a constant wind and assuming production of 200 watts, my wind generator will be able to produce about 4.8 kWh of electricity in a day. So, you can potentially save about 58 cents a day or about $17 a month. However, it is unlikely that the generator will be able to produce a constant 200 watts around the clock.
What is a diode and why do I need it?
A diode is device that only allows current to flow in one direction (see diode at Wikipedia). The wind generator needs a diode between the motor and the battery bank because you only want current to flow from the generator into the batteries (thereby charging them). Otherwise, current could flow from the battery to the generator motor and the motor would spin and discharge your batteries.
Is a rectifier the same thing as a diode?
In short, no. There is a fundamental difference between the operation of a rectifier and a diode. A rectifier is a device that takes in an AC signal and converts it to a DC signal (it in fact uses several diodes to achieve this). However, a diode is a device that only allows current to flow in one direction. You would want to use a rectifier if the generator you were using outputs AC voltage. But if you are using a generator that outputs DC voltage you just need a single diode. The diode basically just lets the current flow from the generator to the battery, and prevents current from flow from the battery to the generator motor causing it to spin and run down the batteries.
Do I need a charge controller?
The simplest solution is just to use a 10-20 amp rated diode between the + wire of the motor and the + of the battery. However, the problem with that solution is that you will need to monitor when the battery is fully charged, or you risk overcharging it. This is where a charge controller comes in handy. The charge controller has a built-in diode, but it has other electronics to monitor the charge of the battery and it can cut off charging when the battery has reached capacity. Some more sophisticated charge controllers can even switch the load from charging batteries to a "dump load" like a hot water heater.
Where can I buy a charge controller?
eBay is always a good resource for this sort of thing. I also recommend the inexpensive controllers from Northern Tool.
How do you keep the wires from twisting around the pole?
It's extremely easy, I don't! In my area, the wind generally only blows in a couple of directions, and it never spins the generator enough to twist the wires. However, I have had emails from people who took my design and added a ball-bearing swivel to detangle the wires.
Are the PVC blades noisy in high winds?
The PVC blades do generate a cutting noise in high winds. It is best to mount the generator far away from your living area so that the sounds don't bother you. However, there is little to no sound in average winds for my area.
Can I use a car alternator?
Car alternators typically require a much higher RPM to produce the needed 12 volts than this wind generator is designed for. There are other tutorials online that detail how to rewire them for low RPM operation. In addition, some people have success using a gearing mechanism to increase the shaft speeds.
Can I make a gearing mechanism to increase the rpm?
I tried this and I failed miserably! However, it is theoretically possible, but you may need to increase the blade diameter to extract more energy from the wind. I tried this using belts, but I could never get the generator to turn. I have heard of people using a chain mechanism with good results. However, keep in mind that some efficiency is lost in the gearing mechanism.
Do you have a wiring diagram for your generator?
If needed, I can create one. However, it is fairly simple. The + end of the diode connects to the + wire of the generator. The - end of the diode connects to the + lead of the battery.