Welcome to Laser Pointer Forums - discuss green laser pointers, blue laser pointers, and all types of lasers

LPF Donation via Stripe | LPF Donation - Other Methods

Links below open in new window

ArcticMyst Security by Avery

LOC RED PROJECT - Battery Question Please

Joined
Dec 27, 2008
Messages
413
Points
0
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?
 





Joined
Dec 6, 2008
Messages
1,581
Points
63
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
 
Joined
Mar 8, 2009
Messages
710
Points
0
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

0
Joined
Mar 27, 2009
Messages
589
Points
0
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.
 
Joined
May 12, 2009
Messages
1,403
Points
0
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

0
Joined
Mar 27, 2009
Messages
589
Points
0
It's great for red diode, but it won't work for BR diode.
 




Top