what to build with....6V lead acid battery, lux III's??

i have some stuff lying around and was looking for ideas on what to build.

i had though of using a CPU heatsink and attaching some lux III (SX1K)emitters to it and making a flood light or lantern.

problem is, the luxes only take 4.5V or so. and the battery puts out about 6.5V
I know a Fatman driver would work, but thats $ i dont have to spend

any CHEAP way to make this work?

Housing to be investigated later.

2 ohm resistor.

2 ohm resistor at input voltage 6.5 and Vf bin K (3.63v typ):


1 ohm resistor at input voltage 6.5 and Vf bin K (3.63v typ):


or in short:

2ohm, ~3w, ~575ma, 82% effecient
1ohm, ~4w, ~720ma, 89% effecient

1 ohm, how many watts? or do i just ask for a 1 ohm resistor? I'm stupid. sorry.

thanks guys

Turbo_E said:

1 ohm, how many watts? or do i just ask for a 1 ohm resistor? I'm stupid. sorry.

thanks guys

Click to expand...

Most of the common resistors out there can handle up to 0.5 watts. From the numbers Meduza posted, with a 1 ohm resistor, you are dissipating 659mW or 0.659 watts in the resistor. With a 2 ohm resistor, you are dissipating 515mW or 0.515 watts. With either resistor, you are over the 0.5 watt limit, which means possible meltdown of the resistor. You can either look for resistors which are rated for 1 watt or higher, or you can use several 0.5 watt resistors to dissipate the power. The formulas for series and parallel combinations of resistors are below.

Series: Equivelant resistance is the sum of the resistor values.

Parallel: Equivelant resistance is the inverse of the sum of the inverses of the resistances. (If R1, R2, R3 are resistor values, equivelant resistance is ((1/R1)+(1/R2)+(1/R3))^-1


Hope this helps

-Blake

How about LM317 linear regulator? the overhead of >1,5V is enough to set the system, and you get constant current, adjustable with external resistor too