445nm Laser dimming, help!

I just built a 445nm laser, bought the diode with aixis from danglasers.com, bought the driver from ebay-

1A 1.2A 1 WATT 445nm Laser DRIVER Circuit Board 1W | eBay

Buttoned it all up, worked great.

Day later, after 18 seconds of the laser running, the beam dims about 50%. I have it running off (6) aaa, and Thought it was the batteries, but new batteries did the same thing, as well as two fresh cr123's. I have a 8.3v 230ma power source, but I measured it with a multimeter to have 10.7v .9a, and the beam did not dim even after a minute, although the heat sink went from ambient to about 110F. Also, when I first assembled, the power source would allow it to burn, now it does not. Have I caused a malfunction in the driver or diode? Do I just need to go with different batteries like the 22600's? Help please, this is my First build, and I just bought parts for a 405nm 100mw that I really dont want to F up. Thanks all.

445nm Laser Problems | Facebook
^link to the album pictures, Sorry couldn't just put them here...

YouTube - 445nm Laser
^and an visually explanational video

Well, my best guess is that your driver, being an LED driver as it is, generates a lot of heat which you did not account for, to dissipate.

Heating up rapidly, it's efficiency goes way down, which means it'll output less current and more heat, hence more power is wasted instead of sent into the diode.

If it were a battery problem somehow, that driver is a switching DC/DC driver, so laser would've worked 100% power on 99% of battery or 1% of battery. The moment the batteries sag under the working parameters, power completely goes out.

It does not fade out, that's typical when using linear drivers like LM317/1117.

Make sure you heatsink the primary IC on your driver somehow (the one with 8 pins there), and see if it makes a difference.

That makes sense but I'm still a little confused by this. Why would 7-9v from batteries cause it to overheat and dim, but 8-11v from a power supply not cause the same issue.

Because it's already dim to begin with, on that PSU, since OP clearly states it's rated for 230mA, where as the pull of that driver would be greater than 1A for sure.

Gotcha. I missed the 230mA part and assumed his initial beam output was similar between the batteries and the power supply. Thx Eud

So what would you suggest, get a new driver, or heatsink the primary ic? And how would I heatsink the primary IC? It is RTV siliconed to my aluminum head heatsink...

You can secure a piece of metal to IC with some thermal adhesive, or just plain thermal paste and have it mechanically secured somehow.

Silicone is not a good heat conductor.

Well other than this you can get a new driver, which is more simple, but more expensive.

Personally I'd work with what I've got there, and try to fashion some makeshift heatsink for your driver.

I would first verify it actually is the driver IC thats overheating. You can just run it off batteries as you would in the portable host, but connect it such that the board is accessable. Power it up and feel how hot the ic gets - be careful, they can run over 100 C before protection kicks in.

If this is the problem, just get a small heatsink for the ic. You can probably buy them, or bend some metal into a |_| shape and glue it onto the chip with thermal adhesive.

I verified that it's a bad ld. I bought a new host and driver combo and the diode is still led-ing. Sucks.