Just another nubm38 gun! And some noobie questions about it

[Tr4hard_Lazer]

Im currently building a nubm38 laser gun and don't have a lot of equipment available to me at the moment. Could i just hook my driver up to the array and slowly tweak the voltage and current till its where i need it measuring with a dc current clamp meter instead of making a test load? I know pretty dumb question but I'd rather embarrass myself then blow 100 bucks lol

 

[RedCowboy]

What driver are you using ?
The array needs a substantial heat sink or a finned sink with fan forced air and you will need to have a reasonable duty cycle, also is your driver battery powered ? If so what kind of battery pack are you planning to use ?
Do you have parts on hand ?
Have you started building yet ?
Have any pics ?

 

[Tr4hard_Lazer]

Yes yes i just started building heres some quick pics of it so far. Lol yes my cable management isn't great at the moment

I'll be bolting it to that big aluminum round rod on the end (2.5 inches by 3 inches) with some indium foil since i wanna keep it somewhat compact and i don't mind the weight too much i can always change it for a compact cpu heatsink with a high power fan in the future. And this is the driver I'll be using just like everyone else which will be mounted on that little heatsink with the blue thermal tacky stuff right behind it (not the biggest heatsink but it should be fine since im using the small nubm38). Most of my parts are still on the way since it's coming from china so i don't have everything yet but I'll be using a 1500 mah 120C discharge rate s4 lipo battery pack (the 2500 mah ones are more then double the price so I'll change it out in the future) to power a small buck boost converter which will then feed the driver since i don't have space for a higher voltage battery

Btw sorry this is my first post on the forums so im not sure how to link links and all that. Sorry if il doing something wrong or something

 

[Tr4hard_Lazer]

Oops not all the photos linked one sec

 

[Tr4hard_Lazer]

There we go had to screenshot my pics since the files were "too large"

 

[aaronnoraa]

Are you sure your clamp meter works with dc? DC clamp meters are comparatively rare as the vast majority of clamp ammeters are AC only. I’m confused how you don’t know what your driver will output necessitating your use of a an ammeter.. didn’t your driver specify what it’s output will be, or is it a driver you built?

 

[Tr4hard_Lazer]

Oops heres the driver specs. It can output 10 amps at 60 volts which is plenty and im using the uni-t ut204 current clamp multimeter thing which has a dc function for the clamp. Yes i have absolutely no idea how the hell it works with dc but based of YT and reviews it should work fine thats why im just double checkin on here before i fry my poor array

 

[aaronnoraa]

Heat sink the shit out of that driver. Who knows what its failure mode is and you don’t want a failed wide open driver, it will get hot hot hot. Also sorry I was writing my last comment while you had posted the specs for the driver while I was asking for that exact info.

 

[Tr4hard_Lazer]

I forgot his name but someone used this exact driver for his and he had it shoved in a drill without a heatsink since it didn't get that hot so mine in open air with this little heatsink should be fine. If it does get a bit toastey I'll get a larger heatsink and somehow make it fit or drill out the bottom of the 2x4 and add a fan since it's kinda just sitting on there right now. And i won't be running it too long anyways since im using an aluminum block for the array so the duty cycle is already kinda eh anyways

 

[Alien Laser]

I did same to mine 50W Laser you have to set the power to 25V first than slowly adjust the A and V use a meter to help you out also you can use a lightbulb as beginning the drivers are nice the don't get hot much you can add a fan for the driver optional for power i use a 18V RYOBI battery , All other battery’s will drain quick 2/3min. Use quality wires mine wires started to smoke and melted from the driver to the battery

 

[Tr4hard_Lazer]

How can i measure the current going into the array since it changes a bit under load? Sorry im kinda new to this just wanna make sure i don't make a 100 doller paperweight. Although if i do im so gonna remove the lense and cut the cover off and pour in resin since that'd be a sick paper weight with the lil diodes visible through the resin

 

[aaronnoraa]

I see capacitors on what appears to be the output side of the driver, be sure to short the output of the driver for a brief moment before connecting the array in case the capacitors are charged- otherwise they will dump as much current as they can provide for a brief blink of an eye and likely blow your array. It looks like there may be a resistor across the output that would relieve the need to short the output but I’m not positive and it’s good practice regardless. You should short it any time the array is disconnected, before connecting the array to the driver. Don’t leave it shorted when you power it on, as common sense would dictate

Back when the most common drivers people used on here were LM317/LM350 linear self built drivers, heaps of peoples diodes became leds due to forgetting to short out caps on the output of their driver before connecting their LD, which sucks double because lm317’s are totally the shit and don’t actually need any capacitor at all on the output to stabilize their output delivery.. they have something like 85db+ of regulation on their output… butter smooth power out of those things.

Sorry, I’m rambling while typing in red bold for whatever reason.

 

[RedCowboy]

I have used that driver, sometimes they hold up and sometimes they don't, you have 14 diodes in the NUBM38 that can take about 4 - 4.5V each at 3 - 4.5A, but that driver also needs a good heat sink.

It's best to run all 14 diodes in series ( both rows of 7 ) Don't try to run the 2 rows of 7 in parallel, that driver won't like doing 6A @ 30V....... much better to do 3A @ 60V with all 14 laser diodes in series.

Remember heat sink the driver or it will fail when it gets too hot, turn the voltage pot all the way up and the current pot all the way down, then adjust it up with the load attached to 3A - 3.5A and see how your battery and the driver holds up, I use an inductive dc current meter, but you can use a multi meter on the current function.

 

[Tr4hard_Lazer]

Yes i think i got it thanks for all your help everyone! Hopefully i don't mess something up or die in some kind of battery explosion lol. this is my first array I've ever had so it's pretty exciting for someone like me

 

[Alien Laser]

Yes RedCowboy is very knowledge in this field when it comes to big power laser's

 

[aaronnoraa]

Yes i think i got it thanks for all your help everyone! Hopefully i don't mess something up or die in some kind of battery explosion lol. this is my first array I've ever had so it's pretty exciting for someone like me

WATCH YOUR EYES and think before you apply power to that thing. Look where it’s pointing and predict any possible reflections it may bounce from. Don’t start fires unless you’re deliberately trying to. Use eye protection. If that’s your first laser or even if it isn’t jfc that’s a lot of power you have no idea how dangerous what you will be holding is.

If you point it in the sky, the more horizontal you have it pointed the more dangerous it becomes and the less control and knowledge you have over what it’s hitting. Also the more horizontal it points the more people will be able to see it, it’s not completely unlikely that someone could get in a car accident from being distracted by it at night so think about that stuff before pointing it up. Stop and listen and look for aircraft before pointing it up. If you can hear or see a plane -anywhere- in the sky STOP and turn it off.