LOC RED PROJECT - Battery Question Please

[Diode_Virgin]

I will be building a LOC red project using the LM317 Ckt. I have some rechargable 9 volt batteries from another project. They put out 10.2 volts when fully charged. Is there a way to lower the voltage (or is it actually even necessary to lower the voltage) before attaching it to the input of the DDL CKT? From what I read we need to run the LOS's at 350 to 400 ma. Any suggestions on how to proceed?

 

[Jimmymcjimthejim]

No need. The DDL driver will regulate the voltage. The 10V battery will work.

 

[LarryDFW]

Laserman;

Use a battery closer to the voltage you need, with more mah capacity.

I like 4.2 volt lithium ion rechargables in all of my Red OC's.

A 2400mah battery will deliver 400ma for several hours continuously.

You can even use a low-cost resistor to drop the correct voltage at full battery charge.

LarryDFW

 

[dr-ebert]

You don't need to lower the voltage. The LM317 does that. However, essentially the excess voltage will be converted to heat - in your case, that's around 7.5V x 400mA = 3W. As my predecessors mentioned, it's best to use an input voltage that is at least ~5V but not too far above for maximum efficiency.

 

[ReNNo]

I use 2x 14500 Lithium batteries for red LPC815@410mA.
It's the best way to power up red diode if you use LM317T.
Batteries can last pretty long time.

 

[Darkarmyofone]

2X rechargable CR2 batteries provides a perfect 6volts for any LM317 driver and plenty of Ma. thats what i use anyways. i guess it just depends on what kind of space your working with. the crs's are pretty small so i prefer them.

 

[ReNNo]

It's great for red diode, but it won't work for BR diode.