Possible to make a green laser with watch batteries?

[ramboing]

I have a laserlyte SCV3 which is 5 mW red laser - LaserLyte ? Sight SCV3

It is 3/4" long and runs on 4 of "377" type batteries, which are 6.8mm diameter watch batteries (different companies have different names for the type, including LR626, SR626, 1176SO, SR66, AG4, 376, and 377. Most don't list their current, but one energizer brand version listed 34 microA).

I want to make a tiny green laser using this same tiny power source (I was hoping I could just use all their parts except to swap out the diode), but from what I understand, 4 X 34 microA isn't enough to power any laser.

Does anyone have expertise on these batteries or tiny green diodes? Here are some specific questions:

1) Do you think this laser is set up in a way to draw a lot more than 130 micro amps from these batteries? Any guesses to how much it actually draws? The batteries have around 20mAh each and the laser claims to run 5 hours on 4 of them.

2) What's my best bet for a tiny green diode that might work? Are there any that really will work on only 130 microA?

 

[ramboing]

I guess 80 mAh of batteries that get used up in 5 hours means that whatever circuits are in the laser actually get 16 mA out of them collectively?

 

[Pi R Squared]

That's milliamps (mA) not microamps, your off by a thousand times. 16mA sounds too low, I am pretty sure it should be more like 35mA or so. There are many under 5 mW reds that run on 3 button cells, I have never seen one that uses 4. A green will use more power than a red so I am not sure if it will work, you would certainly have short battery life at least.

Alan

 

[ramboing]

Yeah the microamps I posted in the first thread was probably just expected draw from a watch that the company listed for the battery and not the limit.

If the math for current to capacity is as simple as I'm guessing (nobody has confirmed for me yet), the laser is actually drawing 16 mA from 4 batteries, and it might be possible to draw more. I guess what I need is someone who is enough of an expert on that type of battery to know whether more current could be drawn from them. Could you draw 40 mA from the same batteries? Would they overheat or something?

 

[WizardG]

I bought a little 532 'keychain' green laser a few years back that runs on 3 LR44 watch batteries. Not for long mind you, and they need to be fresh high quality alkaline types, but it does put out 1-2 mW of green (and it actually came with an IR filtered module!) The button fell into the body of the thing after a month or so and I was never able to non-destructively disassemble it to effect repairs so it's been languishing in my junk box for years. Now that I'm reminded I have it I think I just need to dremel a slot in the outer case so I can harvest the module.

 

[upaa27]

It would work... Just really hard to assemble. Do you want to make a laser watch or something?

 

[ramboing]

Actually, it is about the size of a watch. Looking for a diode - Osram 520 is the most promising I've seen, but it's a bit power hungry. Also probably need some kind of tiny power regulator, driver, or maybe just a resistor - whatever it takes to turn 6V from the watch batteries into whatever current is required to run the diode.

 

[Cel]

Wouldn't it be easier and better to use small li-ions? :thinking:

The size has a massive impact on design and assembly.