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My experience with about 30 new xxxxxfire cells proved only one fact . . . That they were 10 times as likely to fail as a quality "name brand" cell. Safety was compromised after 4 or 5 charging cycles. That was the last purchase of inferior cells. LarryDFW

The numbers I have for Volumetric Heat Capacity are: Aluminum - 2.4 Copper - 3.45 So aluminum by volume is about 70% of the heat capacity of copper. Volumetric Heat capacity is heat energy required to change the temperature of a given volume of a material. Each heatsink would normally...

Good question for a durable build. I think the dissipation of your host would be fine. The copper conducts heat to the body faster due to higher conductivity. The heat capacity of copper is less than aluminum, but the extra aluminum in the host should help in the capacity area. LarryDFW

I agree with your choice of 18650 cells. Brand names are tested to UL1642 standards . . . huge manufacturing capabilities, and continued Research & Development makes them the most advanced cells in the world. LarryDFW

Marco; The most common AR coating is magnesium fluoride, MgF2 . It has an index of 1.38, and is commonly used to make an "A" coating which is good from 400 to 700nm. This is the coating I used to specify for lenses I sold here on LPF. The 0.6NA lens worked very well on 405nm and 650nm LD's...

skir0987; Red LD's are very sensitive to voltage spikes. I have killed a few with Mastech supplies, when I was testing about 30 of them. My guess is the Mastech sent a turn-on or turn-off voltage spike . . . that exceeded the max driver voltage, and that surge killed the diode. LarryDFW

Interesting Green Diode Type Comparison: 808 nm System = 18.75% Efficient (8W input/1.5W output) Direct 520 System = 14.1% Efficient (Nichia specs) LarryDFW

ixfd64; Some drivers can be damaged by large reverse current. With an adjustable power supply, apply reverse voltage thru a 100 ohm resistor and watch the current level. If it climbs more than 100 ma, I would stop the test before damaging the circuit. LarryDFW

Received new shipments of both the NCR18650B (3400mah) . . . and the NCR18650PF (10Amp - 2900 mah) cells. LarryDFW

From Nichia: At 1 watt output, this LD will dissipate 6 WATTS of heat due to it's lower efficiency. This is beyond the capability of most handheld devices. From dissipation work I have done with multi-emitter UV lights, this will require about 2/3 of a pound of aluminum in a light. I would...

Joshua; I have previously used a very similar Mastech supply. It does have spikes when turned on and off. If you ramp up voltage . . . and ramp down voltage it is OK. I did lose some Red laser diodes with it. Here is a good company to buy an inexpensive (~$50) lab supply from: Benchtop...

More Info from Nichia: High efficiencies on both laser diodes. LarryDFW

Ideally, you want about a 1 amp load on the 18650 cell for testing. This would be ~ a 4 ohm resistor. It will dissipate about 4 watts, so you will need at least a couple of 1 watt 10 ohm for a short test time of about 10 seconds. LarryDFW

Having done some commercial laser shows in the past . . . I know that it takes an extreme number of power and time calculations to determine safe exposures to the face. I would think that all of this data would NOT be public at all. LarryDFW

Let us know how they compare. LarryDFW

Three UltraFire cells with 3 different bogus cells inside. I also received one which only weighed about 50% of the normal 48 grams for a current #18650 cell. I haven't opened it up yet, since I know it is bogus. Weight your "off-brand" 18650 cells and throw away any that don't weight 47-48...

Correct . . . Also the back focal length is stated to be 4.8 mm. This is not the same as the G2 lens. and is too long to capture all the power of the 405nm diodes. LarryDFW

andrewb; Very nice job of automating the testing the lenses & laser diodes. Interesting that the G9 lens works so well on all the different frequency diodes. I have some lenses that are specifically coated for Red LDs, and outperformed the std G2 lenses that I used to distribute. LarryDFW

Photon; Check out this "301" thread where I used a module puller (post # 45). Also focused the beam to a point for burning. Larry

Xirrious; At 1.6 watts it should be drawing ~ 1.2 amps (depending on diode). A "name brand" ICR #16340 cell should deliver this current, so that is the cell I would use for best running time. Ultimately, going to a single #18650 cell from a good manufacturer, and an efficient boost...