I can't believe you guys would fall for the old "spymode up the tail pipe" trick so to speak.
There is no way this laser can sustain 200mW for more than a few milliseconds at turn on.
In Fact I doubt they can produce even 100mW.
This was one of the original "ebaysers", I got one that looked exactly like this around a year ago. I posted about it on the CPF, I'll have to search my posts to refresh my memory as it wasn't a memorable product. I don't recall what I got out of it, but it wasn't much. It might impress someone who doesn't know what 100mW really looks like.
The entire laser was only about 4 inches long (about the length of 3-4 of the cr-123 cells) and only weighed in at maybe 3-4 ounces. It had very little mass to it.
I can hardly wait for one of our forum members with a meter to do a review of this, chew em
up and spit em out.
I'm not sure where someone thought that a diode pumped green laser had 20% efficiency?
No that I've come across have ever exceeded ~8%.
For instance, an RPL-350 running at 370mW with it's current tuned for maximum efficiency of say current level 4 would have around 1.4Amps of current running through the laser with a cell voltage of 3.8v (fully charged cell is 4.22v) would be a power consumption of 1.44x3.8=5.47 Watts. If the laser is outputting 370mW, then the efficiency is 0.37/5.47=0.0676 or 6.7% efficiency. Thsi is about the ballpark for all the diode pumped solid state CW green lasers. This number changes up or down a little bit depending on crystal quality and it's doping, but it doesn't exceed 10%.
So, lets work the math backwards to see if it's possible.
200mW output and lets say 7% efficiency to give them the benefit of doubt. 0.2/0.07=2.857 Watts that the laser would consume and the battery would have to provide. 2.857/3.0=952mA (this is a very conservative number on the current as when the battery is under load, it's not going to be operating at 3.0V, but something less.
I think if you take a look at the voltage under load and current curves of CR-123 cells in the CPF link above, you will find that the 1.0amp curve of all of these cells loads down the battery voltage to 2.5V or less. This would mean, the amount of current needed would be 2.857/2.5=1.14 amps of current. It appears that even using the best CR-123 in the CPF post it would be very difficult to get to get 1.14Amps @2.5V for any length of time. This makes 200mW of laser output from a CR-123 possible, but not for long. As for 250or 300mW, only in their dreams or if they leak IR and power testing is done with a lasercheck meter.
Jack
