I have this offset surefire laser:


I discovered that if I remove the middle section w/ the offset (made for clamping to an AR FSB) that I can make a short straight assembly that only holds one cell.  It comes on fine, but I am unsure if running it on 3 rather than 6V might be bad for it over time or something??  

As a short 3 v laser it would be useful to me for a project though.   Or maybe I can get another section or something to make it a straight 6V unit.  

Thx

ETA: as far as i can tell there is no difference in the brightness of the beam whether I am running it with one or two cells across a dark room

With half the voltage you will draw twice the amperage.

Depending on the internal wiring and components you might over heat them.


I wouldn't do it.


.02

or is it that it draws the same current but only makes half of the power output?  

I guess a given load pulls a fixed amout of power by pulling as much availible current at the voltage present to it so I guess you are right.

While the 1/2 voltage requires 2x amperage statement holds true if it is using a buck/boost type driver, given the 24 hour run time I would guess that the current draw off of two batteries is only around a tenth of an amp so. IMO those would have to be some very sensitive components to be damaged by an extra 0.1 amps.



If the diode behaved similar to something like an incandescent light bulb and required 6 volts but was only supplied 3 then yes it would have a significantly reduced output (given the nonlinear efficiency probably a great deal less than half the output,) but if I recall correctly most IIIA laser diodes require less than 3v to operate.

therefore what?

Therefore, given the operating current and voltage it should run at full output just for a shorter length of time.

Remove the tailcap.  Get a digital multimeter and test the amp draw between the negative terminal on the battery, and the threads on the body.  Do this with one cell, and two cells, and report back here.

i will do that as soon as i can...

okay, so it is funny, w/ one battery my fluke 116 says it runs 612 microAmps.  This is in the Ampage setting, the one at 6 o'clock.  However, it does not make the laser discharge... It works the same with eitehr of the two batteries by themselves, BTW.  

With two batteries, the display goes from saying "0.0 DC (micro) A(mps)"  to to "OL" when I short b/t the battery and the threads.  

I did try it w/ the leads in either position.  

I did this w/ a single cell 123a LED flashlight too, it does thte same thing, says "OL" when I tough the battery and the bare aluminum threads w/ the tail cap removed.  It does not run the light.

I think my meter has some feature that is keeping it from working for some reason, like some protective circuitry...

I think you might have the DMM set incorrectly.  If you are measuring amps, it will fire the light when your leads are on the negative end of the battery, and the threads/wall of the light.

i recalled I have a bigger better 176 that I don't usually use b/c its bigger, it works, fires the laser and meters and all.

W/ one battery: 52.3 mA

w/ two batteries: 61 mA

w/ three batts : 68.3

whadaya think??

I gotta go shine this down the street or something w/ different amount of batteries.

seems like there might be a slight diffeence in how bright the beam is between 1 or 3 batteries (jumped out w/ a meter lead) but I can't say for sure.  

you would think there would be visible at 3x the voltage it runs at higer aperage too??  Something about how lasers work I guess...  Like magnets I guess

Well, the difference between 52 and 68 mA isn't very big at all.  That tells me that the circuitry for the laser is most likely regulated, which means it draws the same power from the battery bank, no matter how many batteries you have.  I wouldn't exceed 6v, personally, because some drivers can be overloaded by voltage which kills them.  

If you want to run 1 battery instead of 2, then this is great news for you - runtime may be cut in half with one battery, but it will provide just as bright of a beam.