New project with NUBM37 125W

[Borislav@87]

I received a NUBM37 125W laser array yesterday. First I rewired it from the board to remove some of it and break all the circuits with the pins. Currently, each pin is independent. Previously, 2-3 pins were connected and making a connection. Now everything is broken. I'm using the board for the purpose of the base of the array because I have a bad memory of one of the legs of the array twisting and breaking contact with the diodes. I connected everything in series because the array will be powered by a single 900W driver. I will set the array to run at about 90V and 4A current. I widened the four holes because I will screw the radiator array through them. I have a DC unit with which I tested each line separately and luckily they all work. The laser array will be re-boxed like the previous one I put together with the NUBM35. I'm expecting the other parts to arrive as I only have the array at the moment. I'll probably make a 24V battery from 12 or 18 18650 batteries. I'll figure that out later. Cooling will be active with 3 fans on an aluminum radiator with a length of 200mm and a width of 70mm. That's it for now. I'm waiting for those other components

 

[RedCowboy]

Hey Boris, those NUBM37 have 24 diodes so if you run all 4 rows of 6 in series ( 24 diodes ) then @ 4A you need about 4.125V each, so 99V and 4A

 

[Ricker]

Can't wait to see this finished!

 

[RedCowboy]

Not trying to hijack the thread, but here's an idea I literally just scribbled out that I'm very tempted to build out.

NUBM38's seem to have the best alignment, but even their 2 rows don't overlap as well as they could, so why not knife edge the 7 beam rows...... the single at the bottom is one I have with a weak row so I will only use the 1 strong row as my center row, then knife edge each row onto it and overlap at infinity/max working distance.

 

[Borislav@87]

I couldn't quite get the idea, but that's beside the point. I can't say which of the two arrays has a better and tighter beam, but the NUBM38 produces something like a square in the distance, while the NUBM35 produces something like a circle/ellipse. According to the specification, it says that the NUBM38 is a bit more powerful, but I have no way of judging that. Both seem equally powerful to me. Also, NUBM35 seems a bit brighter to me than NUBM38. I'm waiting for the lenses to arrive and to build some lens. Looking forward to the arrival of the 1250mm long focal length lens

 

[RedCowboy]

There are 2 rows of beams coming out of the NUBM38 with a gap between them and they turn into clusters of long bars, but the clusters don't always overlap that well and of course the bars are not tightly grouped, but we aren't fixing that right now, one thing at a time.

By knife edging each row of 7 beams, rather than the total footprint ( 2 rows with a gap ) I will lap each row of 7 right next to each other and align to all overlap at infinity/max useful distance.

So my output from my KE array will be a solid block of beams that ends up in the space/footprint of just 1 row of 7, it's not perfect, but an improvement and the more you stack, the more power in that one space.

 

[Borislav@87]

The 900W drivers arrived today. I bought 2 to have a spare. The radiator on which I will mount the array has also arrived. The drivers turned out to be quite large. I expected them to be smaller. I hope it comes together with the other stuff

 

[Borislav@87]

This driver failed the tests. This applies to both of the ones I bought. It cannot reach the set values. It can't even reach the values for the NUBM35 58V 4A. Apparently I survived a bad batch. At start it takes a long time to reach more power. See the video

 

[RedCowboy]

Your input voltage of 24v is likely too low for your output voltage @ that current and for those batteries, how many cells are you using total ?

Some 18650 batteries will only output about 7 - 9 amps in reality, others will do more, if you don't have good healthy high drain cells IMR/INR then they cant boost from 24v to 90v @ 4A because at 2A you are drawing 8+ amps from your batteries @ 24v to boost to 90V, so to get 4A out you would be drawing 16A+ ........ if they didn't sag at all, but they do sag, so the current draw will be even higher as the cells voltage drops, putting your 18 cells in series will work, but 6 cells isn't enough if they aren't real high output cells in good health....... what kind of batteries are you using and how old are they ?

 

[RedCowboy]

Here's one of mine driving a NUBM38 ( 14 beams ) @ 3.75A boosting from 8 cells 32V to 55V @ 3.75A
These are brand new INR cells, if I use 8 of my older panasonic NRC cells the boost will drop out after 10-20 seconds.

 

[Borislav@87]

Yes, apparently you need very high voltage from series connected batteries. That doesn't suit me though. The 600W driver copes well even with a 20V battery and without problems powers a NUBM38 array at 4A.

 

[RedCowboy]

Those little boards without a display will often continue to work even if your battery is insufficient, you just won't be getting the power that you think you are, that is you may have tested and seen 4A on your meter at start up, but after 10 seconds running it may have dropped to 1.5A or whatever, but as long as you are happy with the result, that's what really matters.

Looking at your video your 20V battery pack starts at 20.8V ( 5 cells @ 4.16V each ) and ended at 16.1V ( 5 cells at 3.2V each ) and this was after just a few seconds of actual run time, your battery pack can't supply the needed current, you could add cells in series or put another identical pack or two in parallel. So the power supply doesn't need a very high voltage, just a battery pack that can supply the needed current...... was that your cordless drill's 20V battery ?

 

[Borislav@87]

I tried a 20V/4A, 18 pack of 24V, a large car battery. It couldn't handle any power supply.

I tried a 20V/4A, 18 pack of 24V, a large car battery. It couldn't handle any power supply.

Batteries Litokalla 3400mha

 

[RedCowboy]

Is that the battery you were using in your video ?

 

[Borislav@87]

Това ли е батерията, която използвахте във вашето видео?

Yes

 

[RedCowboy]

Well they weren't fully charged, starting was 20.8V and sagging that hard that fast.

You have 18 cells in series/parallel so effectively ( 6 x three battery cells ) you should have had 25V fully charged and your cold solder joints could be a problem too.

What's that you said about a car battery ? Did you try a 12V car battery ?