Voltage reduction

[j611]

I have a 4 volt 4.6 amp hour lead acid battery that I want to use to power a 3 volt flourescent light. The question I have is, what is the best way to drop from 4 volts to 3 volts and not use up the current I want going to the light? I would like to retain as much of the 4.6 amps from the battery so the light will burn longer.
I will be grateful for any help.

[russlk]

Since high voltage is required to operate the flourescent light, there must be a PWM power supply already involved. It likley will operate at 4 volts, or can be modified to do so.<p>[ August 27, 2003: Message edited by: Russ Kincaid ]</p>

[j611]

The flourescent light I am using orginally operates on two AA batteries ( 3 volts ). I am wanting to power it with the 4 volt battery I have. Thus I need to reduce the voltage by 1 volt.

[Chris Smith]

You will find most fluro drivers are very tolerant and actually work a little better at that higher voltage. I’ve been building and modifying the little units for 20 years, and one volt higher has never damaged any of my units. I recommend a minimum of one volt or more on the 12 volt units.<p> Most 12 volt units I run up to 16 volts for brighter performance and also I modify the "Main Transistor" with a heavier wattage unit of the same Characteristics to run my units full time 100% duty cycle with larger and much brighter tubes. Plug it in to 3 volts and measure the temperature of the main transistor if you can, or the sealed unit as a whole and then try it again with 4 volts. Unless it gets real hot, real quick, and starts flickering, it should be fine. <p>Also Remember Transistors were made to run at temperatures that will boil water, so burning your finger, isnt a real test?<p>Most of my units that run hot, but safe, I use a larger heat sink and leave it at that.<p>[ August 27, 2003: Message edited by: Chris Smith ]</p>

[josmith]

Lead acid cells are 1.2v so it's probably 3.6 volts not 4. The light will run fine on 3.6. <p>If you were to have more voltage to drop a switching regulator is the most effient but with that little difference in voltage you'd lose more than you gain.

[Dean Huster]

Lead-acid cells are 2 volts each; NiCd and NiMH are 1.2 volts each.<p>Dean