Question about power output from different battery types

[xsv161]

I'm currently using two 16340 batteries for my laser. What kind of power difference would I see if I threw in one 18650 battery? Would I be able to safely look at it for short periods of time (a few seconds) without protective eyewear?

M140 diode
1.25A driver (non boost drive)
3E glass lense

 

[corey5188]

NO!

The battery isnt going to effect the power output much, because your driver is what determines the current, not the battery. Depending on your driver, 1 battery may not even power it. If you are using a linear drive, it would still probably get enough forward voltage to power the diode, but it would die faster, and stop lasing before the battery died completely.

As far as I know, there is no way to power a M-140 with such little power to make it eye safe (i.e. under 5mw). I dont think it would even lase with such little current necessary.

If you want to use it without goggles, go outside. Make sure you arent looking at the dot on anything unless its 50+ feet away and make sure that there is ABSOLUTELY nothing that could reflect the laser back at you...

 

[xsv161]

Thanks for the info! Looks like I'll just have to pick up a low power laser to use around the house and to torture my cat :yh:

 

[cheech226]

i've run m140 diodes driven by a linear driver with one cell. all it does is reduce the output. with ~8V in the laser has full power. Dropping to one cell (~4V) will give a much lower output.

 

[Bionic-Badger]

Remember that if your M140 is lasing at all it is at dangerous power levels.

 

[Hemlock_Mike]

Remember that these diodes run on current. Any stray resistance in connections
will result in power loss. That said ----
Look at the internal loss in your cells. Old cells can get high resistance and cut the
efficiancy of the laser.
There is a thread on LPF to check the condition of your cells. You may want
to get rid of the "bad" ones.
HMike

 

[Fracker]

In my opinion you need to check the specs of your driver and stay within the required voltage. Check the current your driver is set at make sure your batteries will supply enough current. That's a bad ass diode so why under drive it? The battery will effect the output. If you have 2 1000mah batteries and your driver is set for say, 1.8 amps your batteries can't supply enough current for maximum output. While you'll have decent output for a short time you'll drain the batteries quickly. I have a few 5mw toys I use to play with around the house. But for my 2 watt build I want the maximum power I can get. I know your thinking. It would be awesome to have a laser that you could set the power output from 5 mw to say 2 watts whenever you like. Not sure it's possible.