2x 18650's to much?

I finished a build today for a friend. His module is an 800mw or .8w, 445nm that calls for up to 7.5v power supply. So I opted for two of the 18650 li-ion cells. Whic is a 7.4 pack. Now Im starting to worry about wheather or not that was such a good idea. That 7.4 s nominal voltage, right? They are like 8.4v charged up good and hot arent they? Should I instruct him not to firethe LASER until I can install a resistor or two in line?

What driver did you use?

The driver came prepackaged on the module. It was an e-bay laser. Not allot of info was provided.

Do you have a link?

I have an e-bay idem number 180714744989

Sorry I had to get off the phone to figure out how to do that!

There are two things that I noticed right off the bat.

First a working range of 7v to 7.5V is terrible. I am am thinking this is because the dropout on the driver is high probably close to 2.5V. I am sure it can take 8.4V which is the fully charged voltage of two Li-ions but it probably produces too much heat drooping that extra volt to achieve the 45 seconds duty cycle it promises so he chose a range that will let it run that long before overheating. A .5V working range is pretty much useless in a handheld unit and a 45 second duty cycle in a labby or projector is just as useless so the unit is just basically useless.

The second thing is he claims it has a dot not a line which I am pretty sure the output is going to be a line due to the multimode nature of the 445 and that thing does not look like it has corrective optics crammed in there.

Now that is a hell of a price he is asking for that unit. It has a extremely cheap linear driver, probably an A series diode and three element lens based on the efficiency looking at his operating current and power output. I would say it is price about double what it is worth if it actually would work for either a hand held unit or a labby. But it does not fit the mold for either.

If you want out of the unit I would check the output and if it is not a dot as he states I would suggest making him take it back and if he does not want to leave him appropriate feedback and file a item not as described claim.

You can get a unit that can do 1W off a single Li-Ion with a high quality boost driver, a 90+ second duty cycle, M140 diode and in a standard 12mm housing for under $100 from me or a few other members here that have similar items for sale.:beer:

Really... I'll sure keep that in mind for my personal build. My friend bought this one and just had me assemble it for him. It is a dot, but it seems to be a very large dot. My goggles are for 532nm so I cant get down and dirty with it. I have a diode and goggless on the way. He has some goggles on the way too. All we can do right now is shine it up in the air.
I want you to know I really appreciate your input on this matter. Thank you very much!

Well if you get a chance I would like to see a picture of the dot. I am guessing by what you are saying it is a fixed focus unit?

Gimme a minute, Ive got a photo, I just have to resize it real quick.

oh my, I cant do that in the reply can I?

Sure you can. Just use the insert picture button up top. The best way to get the picture is to shine the laser on a dark material about 20 feet away then go up to the item that it is being shined on and get a pic. This is a standard M140 and 9mm diode @ about 30 feet. With a three element lens.

Yea try getting something of dark material like a black painted metal or or a cd case then place it about 20 feet away from the laser. Shine the unit on it then go over and snap the picture of the dot. That picture has way too much reflection due to the light color wall you are shining it on and the laser was only a foot or two away from the target. The further the distance the better you can determine the beam profile.

Ok, its a pistol, A Colt 1911 to be exact, so it only has a momentary switch on it. I'll have to do that when I have another set of hands around. And in that picture I was hiding my eyes behind the camera. I just finished assembly a coupple hours ago!