1.7W 808nm Saik TO-3 Diode

G'day,

So i bought a 3W TO-3 diode from eBay a while ago to put in a host and i have finally gotten around to making it happen.

the Saik is just big enough to fit the 39mm TO-3 package into the space where the reflector lived, so i chose it.

Machined up the 2 part heatsink that clamps the diode:





Made a focus adapter



Now the 3W diode is rated for 3A i am using 8x AMC7135 board, but to my testing the thing doesn't put out 2.8A, closer to 2.1A.

The diode is also case positive, hence why im using a negative regulator, heres my wiring diagram:



Here are the power meter tests on Low, Medium and High. Notice the dip starting to occur on the high mode:





High mode only, it dropped over 700mW in 45 seconds!


Im not sure whats causing it to drop in output so much, wether it be the regulators are getting hot (4 of them are thermally glued to a copper heatsink), battery cant handle the load (using a 32600 Lithium cell),insufficient heat sinking of the LD or a inefficient diode.

Im pretty disapointed in this diode, i thought it would of performed alot better, it should have got me into the 2W range easily.
I may change the LD to one with a FAC lens and downgrade to a 2W diode.

Heres a video of it running under night vision:


Thanks for looking,

Fiddy.

Awesome! I am really liking your high power to-3 builds.

Sounds like you might not have enough voltage? If you can, measure the voltage over the diode and across the negative in and out of the AMC drivers. If the diode Vf is abnormally high for an IR diode or the driver has less than 0.3v you should try running it from 5v and see what happens. If there is enough voltage then it might have something to do with using two drivers with modes in parallel. To fix it remove the microcontroller from one of the boards and run a line from the plus pin of the AMCs on one board to the plus pin of the AMCs on the other board.

Great build. The high power diode gives so bad beam spec.

Maybe the diode is extremely under spec? Love the build Fiddy. As always.

benmwv said:

Awesome! I am really liking your high power to-3 builds.

Sounds like you might not have enough voltage? If you can, measure the voltage over the diode and across the negative in and out of the AMC drivers. If the diode Vf is abnormally high for an IR diode or the driver has less than 0.3v you should try running it from 5v and see what happens. If there is enough voltage then it might have something to do with using two drivers with modes in parallel. To fix it remove the microcontroller from one of the boards and run a line from the plus pin of the AMCs on one board to the plus pin of the AMCs on the other board.

Click to expand...

The Vin to the driver is 4.2V, and the Vf of the diode at 3W is 2.1V. i dont think these drivers drop out ~2V's?

Im not usining 2 drivers, theres only 1 driver board, the other board is a contact board for the battery.

Oh, not sure what is wrong then. Did you measure the tail cap current to be 2.1A?

It is possible two of the AMC chips weren't soldered correctly or are fried. 6 x 350ma = 2.1A

I've been working on some stuff with AMC7135s, and I think I have a board you could use for this if you can't fix the driver you have. PM me your email and I'll show you some pics and details.

Wow that looks like one fat, flat beam

Cool to see it with night vision though.

Hey Fiddy maybe its the resistance in the tailcap switch. I just built a couple of torches running an 8 x 7135 board and could only measure ~2 A with a MM in series with the LED. I remodded the tail cap switch with beefy copper contacts and the ground connection to the driver and the current shot up to just under 3 A. I was using the 3040 mA board ie the one with the 380 chips. :beer: