Wind turbine charged remote light

Discussion in 'The Projects Forum' started by 1nutlouie, Jun 7, 2011.

  1. 1nutlouie

    1nutlouie Thread Starter New Member

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    I am working on a project that will use a 125W wind turbine to charge a 12v car battery. The battery will power around 3 1 watt LED's and possibly a security camera and recorder that will draw around 1 amp. The lights will only be on at night.

    I hooked a 3W LED light directly to the wind generator and it worked great until the wind picked up and the light burned out. Same with an incandescent trailer light, so I guess I need to regulate the voltage or current somehow. I assume that a light hooked directly to the battery will see the high volts/current during high winds.

    Can someone help me with a circuit that will protect my LED's and camera/recorder and let them see a constant voltage and current no matter what the wind is doing?
  2. Kermit2

    Kermit2 Well-Known Member

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    A voltage regulator is an easy circuit to build, but you will need more than that.

    You will need a 'charge controller' for the battery, and you must also have a 'dump load', which will get voltage from the wind genny and waste it as heat on those occasions when the wind genny has charged the battery completely and is still trying to pump more in.

    Google those words and do some more reading.
  3. wmodavis

    wmodavis Active Member

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    The application you described is the turbine connected to a car battery then to the lights etc. In this simple, though not optimum, system it will work with several caveats. One question however on your tests which burnt out the lights - Did you have the battery connected to the generator output or ONLY the light connected to the generator?

    The battery will itself perform rudimentary regulation at its charging voltage of roughly 14-16 Volts. And if you have a suitable current limiting resistor in series with the LED it should not burn out. If you use an automotive type 12 V incandescent bulb same thing though it wouldn't need a resistor. If either light is connected to the generator without the battery also connected, the output voltage of the generator will increase with wind to the point of causing excessive current to flow and burn out the lights.

    Regarding Kermit's suggestion that you will 'need' a charge controller, IMO that is partially correct.
    It should work without the controller BUT...
    a) the battery will likely be over charged in high winds
    b) the battery could be over discharged during low or no winds.

    Both a) & b) will severally reduce battery life and the voltage available for the load will vary with wind speed. It will be cheaper to buy a charge controller to deal with a) & b) than to keep replacing over charged/discharged batteries unless you have a free supply.

    The functions of the charge controller are
    1) to sense when the battery is fully charged and turn off generator charging current so as not to overcharge the battery.
    2) to sense then the battery is discharged some, but not enough to severely reduce battery life, and switch off power to the load.

    Like I said 1) & 2) are not required if you have an adequate free supply of batteries and the time to go to the sight and check/maintain the batteries.

    Good luck on your project but a big part of any project is learning the characteristics of the intended system components to use them properly in your design (project) to achieve your objectives. My suggestions are - before connecting any components together
    *sit down and list your objectives.
    *list what components you think would work together to meet those objectives
    *gather information on and study every component you propose so you know its operational parameters
    *evaluate those parameters against your objectives
    *keep revising the above steps until you come up with what you believe will be a usable solution
    * NOW you can connect it up and test your design.

    To bypass all that cumbersome, involved, time consuming, mind expanding activity you can eliminate any step and bear the consequences or you can just pay someone else to do it or you can just use the design of someone else.

    Your choice.
    Sorry for the long reply.
  4. wayneh

    wayneh AAC Fanatic!

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    Not necessarily. The simplest regulator of all is a big battery, where by "big" I mean relative to the generator capacity. It will buffer the otherwise widely variable output from the generator. With no other control, you risk the problems detailed above, but a simple battery will prevent most occasions of overvoltage to the load that you have seen without the battery hooked up. By "most" I mean until the battery is destroyed by overcharging.
  5. SgtWookie

    SgtWookie Expert

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    Automotive batteries are not recommended for deep-cycle use; they will fail quickly when used as such. You really need a deep cycle battery.

    Automotive batteries have thin plates so that they can release a lot of energy in a hurry to start an engine; then they need to be charged back up right away, or the chemical reaction will quickly destroy the plates.

    Deep-cycle batteries have much thicker plates. They don't have the ability to release as much energy as auto batteries do in a short time, but their plates won't fall apart quickly either.
  6. THE_RB

    THE_RB AAC Fanatic!

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    Another issue with wind is that it produces power at the square of wind speed (or is it the cube of wind speed?) so in very high winds you don't want to rely on generator into a fixed voltage battery as it will burn out the generator.

    So "battery voltage regulation" might be best by open-circuiting the generator and letting the blade inefficiencies limit top speed. This should work well enough as you can assume that the times the battery voltage is high will correspond with times of high wind speed.
  7. wayneh

    wayneh AAC Fanatic!

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    It is indeed. Drag force increases with the square, more or less. Since Power = Work per Time, and Work = Force * Distance, that means Power = Force * Distance/Time or simply Force*velocity.
  8. electronis whiz

    electronis whiz Member

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    as long as the battery is there you should be ok. but if you want to run it off the generator or just to be safe you should use a voltage regulator with the leds these may be found at readio shack or websites like marlin p jones, electronic goldmine. these are usily fairly cheep and if they dont give you hookup info you can always google the part number or try all data sheet.com. just get one that will provide sufecient curent and the right voltage. you may also need a heatsink for the regulator also usily at the same place too.
    most industreal wind generators have some sort of breaking mechinism so that high winds will not cause surges and also prevents them from going so fast the force shaters the blade. if you want to do somthing like this i would put a switch or relay with it that would short out the output or run it though a high draw divice this will cause the generator to have to work harder and will slow it down.
  9. THE_RB

    THE_RB AAC Fanatic!

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    Thanks Wayneh even as I typed it I thought I might be confusing my "wind turbine" facts. :)

    Power is the square of the turbine diameter, and power is the cube of the wind speed.

    Which is why they make them MASSIVE and put them on top of very windy hills. ;)
  10. wayneh

    wayneh AAC Fanatic!

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    Yup, wind speed goes up dramatically as you gain elevation above the ground. All the factors conspire to give enormous economies of scale. The only reason they don't get even bigger is the unfavorable physics of huge objects. Despite all the experimenters out there, "small" wind is really tough to do economically, compared to "big" wind.
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