Help with first build

[rizzlyfox]

So I recently bought a 3w laser from DTR's shop with a suggested operating current at 2A and maximum of 2.4A. When it arrived to my place I hooked it up to a singular protected 3.7v 18650 with a continuous discharge of 4A. I did not tweak the driver whatsoever prior to hooking it up to the 18650. The laser had a small flash of brighter light but then dimmed down and it looked like a 5mw laser pointer. This is indeed my first build although I have been messing about with different lasers and modifying them, but this is my first time actually putting together a laser.

I also tried using two 18650's and it was still dim. If anyone has suggestions please help me out lmao

 

[Ricker]

Unfortunately it died, it is now "LEDed." For some reason or another it either had too much current, or not enough of a heatsink and burned up due to thermal runaway.

 

[RawCuriosity]

So I recently bought a 3w laser from DTR's shop with a suggested operating current at 2A and maximum of 2.4A. When it arrived to my place I hooked it up to a singular protected 3.7v 18650 with a continuous discharge of 4A. I did not tweak the driver whatsoever prior to hooking it up to the 18650. The laser had a small flash of brighter light but then dimmed down and it looked like a 5mw laser pointer. This is indeed my first build although I have been messing about with different lasers and modifying them, but this is my first time actually putting together a laser.

I also tried using two 18650's and it was still dim. If anyone has suggestions please help me out lmao

Sadly its dead, either from poor heat dissapation or too much current or a polariaty issue. Was the laser properly mounted in a heatsink? Was the positive and negative connected correctly? And was there a CC (Constant Current) driver between the battery and the diode? A Li-Ion protection circuit wont limit the output current and if the diodes max operating current is 2.4a then a 4a surge would kill it. You get drivers from DTR or Survival Lasers which you can buy for different operating currents, in your case 2a or 2.2a. You could also choose to use a bench supply but be careful with the knobs as it's easy to slip and kill a diode.

Also I must ask, were you wearing laser safety googles as 3w laser will 100% blind you, if you weren't some would say it's lucky the diode died.

 

[nmbusa]

Sadly its dead, either from poor heat dissapation or too much current or a polariaty issue. Was the laser properly mounted in a heatsink? Was the positive and negative connected correctly? And was there a CC (Constant Current) driver between the battery and the diode? A Li-Ion protection circuit wont limit the output current and if the diodes max operating current is 2.4a then a 4a surge would kill it. You get drivers from DTR or Survival Lasers which you can buy for different operating currents, in your case 2a or 2.2a. You could also choose to use a bench supply but be careful with the knobs as it's easy to slip and kill a diode.

Also I must ask, were you wearing laser safety googles as 3w laser will 100% blind you, if you weren't some would say it's lucky the diode died.

hello
arent you "curious" as to what he stated b4 giving your assistance?
the fox states "I did not tweak the driver whatsoever prior to hooking it up to the 18650"
I dont think dtr's ships untested crap!!!

 

[Gryphon]

Can you post a picture of the module with the back half removed? Maybe something has shorted to the inside of the case.

 

[RawCuriosity]

hello
arent you "curious" as to what he stated b4 giving your assistance?
the fox states "I did not tweak the driver whatsoever prior to hooking it up to the 18650"
I dont think dtr's ships untested crap!!!

To my knowledge DTR does not sell NDB7875s with a driver he only sells them as a raw diode or with silicone leads sodered on, rizzlyfox when your say "tweak the driver" do you mean the Li-ion protection curcit or an actual laser driver from DTR?

 

[paul1598419]

Unfortunately it died, it is now "LEDed." For some reason or another it either had too much current, or not enough of a heatsink and burned up due to thermal runaway.

When these diodes die so quickly, it's not because of inadequate heat sinking. It is because your current was too much. You can make a dummy load and measure these drivers before you use them. I always do that.

 

[rizzlyfox]

Sadly its dead, either from poor heat dissapation or too much current or a polariaty issue. Was the laser properly mounted in a heatsink? Was the positive and negative connected correctly? And was there a CC (Constant Current) driver between the battery and the diode? A Li-Ion protection circuit wont limit the output current and if the diodes max operating current is 2.4a then a 4a surge would kill it. You get drivers from DTR or Survival Lasers which you can buy for different operating currents, in your case 2a or 2.2a. You could also choose to use a bench supply but be careful with the knobs as it's easy to slip and kill a diode.

Also I must ask, were you wearing laser safety googles as 3w laser will 100% blind you, if you weren't some would say it's lucky the diode died.

The diode was mounted in a heatsink, possibly one not sufficient enough. The positive and negative was connected correctly, there was a CC between the battery and the diode, and I was indeed wearing 450nm protection glasses.

 

[rizzlyfox]

To my knowledge DTR does not sell NDB7875s with a driver he only sells them as a raw diode or with silicone leads sodered on, rizzlyfox when your say "tweak the driver" do you mean the Li-ion protection curcit or an actual laser driver from DTR?

I mean the driver, but that was well after the diode was dimmed. And by 'tweaked' I mean that I was changing the current regulation on the potentiometer

 

[rizzlyfox]

hello
arent you "curious" as to what he stated b4 giving your assistance?
the fox states "I did not tweak the driver whatsoever prior to hooking it up to the 18650"
I dont think dtr's ships untested crap!!!

Yeah I'm almost positive it was me lmao, possibly too much ampage that the driver couldnt handle

 

[rizzlyfox]

Can you post a picture of the module with the back half removed? Maybe something has shorted to the inside of the case.

I've already desoldered the driver from the diode, as well as removed the laser diode from the module so I can reuse the heatsink for other projects. Would it still be the same if I were to show photos of the diode and the driver?

 

[monkas6565]

So I recently bought a 3w laser from DTR's shop with a suggested operating current at 2A and maximum of 2.4A. When it arrived to my place I hooked it up to a singular protected 3.7v 18650 with a continuous discharge of 4A. I did not tweak the driver whatsoever prior to hooking it up to the 18650. The laser had a small flash of brighter light but then dimmed down and it looked like a 5mw laser pointer. This is indeed my first build although I have been messing about with different lasers and modifying them, but this is my first time actually putting together a laser.

I also tried using two 18650's and it was still dim. If anyone has suggestions please help me out lmao


1

Sounds like the driver or diode may be damaged. Running it without tweaking the driver could’ve caused an issue, especially if it wasn’t set for the right current. Double-check the driver settings, connections, and ensure your power source is stable. You might need to replace the diode if it’s already fried.