Dorcy 1 AAA circuit in a 3 d mag

I'm trying to milk the battery on a 3d mag mod one 3 watt lux emmiter light by putting in a circuit from the dorcy 1aaa light so i can get constant voltage output, anyone done this before, the input voltage battery i'm going to use for circuit can either be 4.5 volts (alkaline) or 6 volts (rechargeable battery pack)? or what other voltage input can it be in order to keep the 3 watt lux alive /ubbthreads/images/graemlins/thinking.gif.

Neither of your input voltages are appropriate for this circuit. Since it is a stepup circuit [which BTW regulates to 5V if not overloaded by the presense of an LED] you want your input voltage to be less than the Vf of the LED.

the vf of my 3 watt lux is 3.9 for 1 amps, what should my input voltage be if i want to use the dorcy 1aaa circuit in it, would 3 volt in be ok, plus what resistor size should be use in order to bring down the voltage from either 4.5 v or 6 v battery? /ubbthreads/images/graemlins/help.gif

If you are using a 3 D cell light (nominal 4.5 volts) you should use a buck converter to lower the voltage in a controlled way or use a resistor to eat up the voltage over 3.9 volts.

You want 1 amp at 3.9 with an input of 4.5. That means that you wnat to drop .6 volts across the resistor. At 1 amp the resistor should be .6 ohms and should be at least a 1/2 watt resistor.

Daniel

cool thanks, now only if somehow i can use both of these the dorcy and the buck in the ciruit, one down down regulate the voltage when it gets too high and one to up regulated when the voltage of the batteries drops below 3.9 volts

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gadget_lover said:
If you are using a 3 D cell light (nominal 4.5 volts) you should use a buck converter to lower the voltage in a controlled way or use a resistor to eat up the voltage over 3.9 volts.



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While this is true enough for *new* cells, by the time your battery is only 25% used (1.3 Volts per cell) Vbat will no longer be more than Vf, a buck converter will be useless....

And you'll be in the dark with 75% of your battery left. Right?

Doug Owen

As Doug Owen pointed out, the buck converter would probably be more appropriate with a lower Vf luxeon or a higher battery voltage (4 cells). The LED does not go dead when the battery drops below Vf. It simply drops in intensity till it reaches the threshold value for the LED.

There are buck/boost converters available, some of which are the buckpuck (wired just right) and the Wizard. The problem is the 1 amp that zzublogan mentioned. The Dorcy AAA circuit will not provide 1 amp, as near as I can recall.


Daniel

the "buckpuck", lol, where can i get one of these? i need a good buckpuck, one that does not shrew me over... /ubbthreads/images/graemlins/yellowlaugh.gif


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gadget_lover said: /ubbthreads/images/graemlins/yellowlaugh.gif
As Doug Owen pointed out, the buck converter would probably be more appropriate with a lower Vf luxeon or a higher battery voltage (4 cells). The LED does not go dead when the battery drops below Vf. It simply drops in intensity till it reaches the threshold value for the LED.

There are buck/boost converters available, some of which are the buckpuck (wired just right) and the Wizard. The problem is the 1 amp that zzublogan mentioned. The Dorcy AAA circuit will not provide 1 amp, as near as I can recall.


Daniel

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Lots of Buckpucks here:

LOTS 'O BUCKPUCKS

LOTS 'O BUCKPUCK INFO