Dim 445nm Build

[Nitroamine]

I'm having some problems with a >1.4W 445nm build. After working perfectly for half an hour, the laser began to flash at a higher output when turned on and then instantly switch to a very low power output. Just now it stopped flashing and is consistently outputting the dim dot. Low as in <5mw.
The two attached photos show a focused and unfocused beam at around 1m from a wall.
It's running on a buck driver at 1.1A and on 2 18350 cells. The cells are protected (though they still measure 3.8V) and although they are cheap, I don't think they can just lower their output by a huge margin instantly.
The diode is a M140 and it runs at a reasonable temperature.
Thanks for any help; I don't want to pester the seller just yet in case it turns out to be a stupid mistake on my part.

 

[ryansoh3]

Uh oh, you might want to consider the possibility of the diode being LED'd.

Have you checked the connections between the driver and the diode? If they disconnect and connect again, a capacitor may discharge and might have killed the diode.

Cheers! :beer:

 

[Nitroamine]

OK, so I loosened the screw holding the copper module to the heat-sink for the first time and the wires connecting to the diode seem to be fine, held on with heat-shrink tubing. I can't see the driver because it's attached in some way to the bottom of the heat-sink, probably with solder or glue. I'd rather not try and take it out in case I further damage it. Are the symptoms compatible with low battery power? My charger seems to successfully charge them, but then again, it's an Ultrafire. My multimeter doesn't seem to want to measure the milliamp output.

 

[Lethere Belight]

I have several "good" ultrfires. I was having a similar issue. Would run about 45 seconds and start blinking.
Shut off for a minute ot two and it would work but only about 45 sec.
Changed batteries and it worked.
This happened off and on for a few days.
I finally realized it was only happening with the same battery.
I guess a "bad" ulrafire. Got them at the same time but this one just won't put out.
Would be worth trying GOOD FRESH BATTERIES.

 

[Fiddy]

when you say working perfectly for half an hour, you mean you had it on non stop for 30 minutes?

 

[Nitroamine]

when you say working perfectly for half an hour, you mean you had it on non stop for 30 minutes?

No, if I did I think it would have died long before that. :crackup:
I meant that I was messing around with it for that long after I put it together. The laser was on for probably 10 seconds at a time, with a lot of time to cool down between each use. I guess I should have worded it better.

 

[Fiddy]

what driver are you using?

 

[Nitroamine]

what driver are you using?

It's a modified DX buck driver.

 

[Nitroamine]

I have several "good" ultrfires. I was having a similar issue. Would run about 45 seconds and start blinking.
Shut off for a minute ot two and it would work but only about 45 sec.
Changed batteries and it worked.
This happened off and on for a few days.
I finally realized it was only happening with the same battery.
I guess a "bad" ulrafire. Got them at the same time but this one just won't put out.
Would be worth trying GOOD FRESH BATTERIES.

I tested the cells and I'm getting 3.82V from three of them when charged and the fourth one is almost completely empty and the charger doesn't want to fill it up. According to a review, they are meant to fill up at 4.2V and settle at around 3.97V after 15 minutes of use. The cells are sold as 3.7V but my charger has a switch to choose between 3.0V and 3.6V. Do you know if buck drivers require such a specific voltage?

 

[Fiddy]

got the link to your buck driver?

Testing batteries by puting a voltmeter across them is not good practice, you must put the battery under load and monitor its voltage.

 

[Nitroamine]

got the link to your buck driver?

Testing batteries by puting a voltmeter across them is not good practice, you must put the battery under load and monitor its voltage.

I honestly don't know what model the buck driver is. You'd have to ask Blord, the user I bought the laser from. He said that the diode has died and he agreed to send me a new module and take a look at my one, in case the driver caused the early death.

By the way, do you by any chance know how to reset the protection circuit on a Li-ion cell? I've tried the usual methods (using the trickle charge from the charger and jump-starting it) and so far nothing's worked.

 

[Fiddy]

ok.

Best way to reset is to remove the protection circuit from the battery then hit it with a hammer.