Author Topic: Regulate Voltage without throwing away power  (Read 905 times)

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valterra

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Regulate Voltage without throwing away power
« on: December 23, 2006, 08:33:25 PM »
I have a minigen from Windstuffnow Ed.


I have it mounted with PVC blades, and, in my "sticking it through the sunroof of my car and driving around" tests,  the little bugger generated as much as 280 volts!  According to Ed, the current is low - like 20mA, but this thing creates high voltage at very low speeds.


Now that everything is all assembled, I want to put it to some practical use.  Ultimately, I want to light LEDs.  I have several 12v LED night lights and many, many single LEDs.  


The main issue I'm wondering about is the wildly varying voltage.  I don't want to burn out my LEDs!    


The idea was rectifying the AC and making a simple battery-charging circuit.  That way, the battery would actually run the lights, and the minigen would trickle-charge the battery.


But if I'm taking an AC-generating PMA and putting a battery in the circuit, which would limit the voltage to somewhere in the area of 12v, am I just throwing the rest of the generated power away?  


To clarify:  this generator shoots way over 12v at very low RPMs.  It is a high-voltage, low current machine.  The amount of current generated makes it perfect for LEDs, but I'm afraid that hooking them directly up to the (rectified) minigen would either not light all of them (low rpm) or blow them up (high rpm).  


I'm also afraid of "throwing away" all the extra voltage this thing will create.  Am I mistaken here?  Is the extra voltage "absorbed" by the battery, to be released steadily as 12v?


Any thoughts?


mobile (at) jeharper (dot) com


Thanks!!

« Last Edit: December 23, 2006, 08:33:25 PM by (unknown) »

Norm

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my thoughts....works for me...
« Reply #1 on: December 23, 2006, 05:15:44 PM »
  You're just measuring open voltage....when you

hook it to a 12volt battery ....you'll find that

the voltage will drop way down...you will not be

throwing away the extra voltage... you're right

it will blow some LEDs at high rpm even possibly

low rpm.....So instead of lighting LEDs directly..


   Make 6 volt battery packs of Ni-Cad cells or

AA NiMhd then charge them with the Mini Gen  and

light LEDs in a 6 volt circuit  with one pack

while you're charging the other.

    ( :>) Norm.

 

« Last Edit: December 23, 2006, 05:15:44 PM by (unknown) »

wooferhound

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Re: Regulate Voltage without throwing away power
« Reply #2 on: December 24, 2006, 10:13:01 AM »
As I understand it . . .

When you attach a battery to a high voltage generator, the generator voltage will be pulled down to the battery voltage and the Current will multiply upwards from your original measurements. Watch your Battery voltage though. Even when Trickle charging, your battery will eventually try to charge up to the Generator voltage.


Here is Otherpower.com page about making LED Lighting

http://www.otherpower.com/otherpower_lighting_leds.html


Here is how to make LED lighting with a cool Resistor Calculator on the page

http://ourworld.compuserve.com/homepages/Bill_Bowden/led.htm

« Last Edit: December 24, 2006, 10:13:01 AM by (unknown) »