100w CW handheld laser?

[deltawars]

I want to make a 100w handheld laser, I found this diode and the LPHD8834106 battery I found here has a continuous discharge of 156A and a Max discharge of 312A, I would use 4 of them for a total of 10.4Ah which would give me about 4.368 Minutes of Continuous power, Although I would probably only power for like 3s max because of heat issues. I still haven't found a constant current driver, but do you guys think It could be done?

 

[crazyspaz]

No. Good luck getting anything remotely handheld that can manage the heat of the those batteries and that diode, which btw, is supposed to be water cooled. Even if you do, good luck working that output into anything usable.

 

[shokkunlasers]

Ok you have a battery and a diode.

Now how about Cooling system, optics and driver ?

1.
imagine over 120W heat in a handheld!
watercooling systems for such diodes can be bigger than a regular desktop pc

2. you need a lot of optics to get a decent beam out of such a large bar diode
most likely need a fiber coupled one

3. over 100A out of a small driver?! even cables that you use for those kind of currents are thicker than our standard drivers are long.

I hope you see it's not that easy
maybe a 40W diode would be possible but for what a big bulky device not really handheld anymore that has a freaking dangerous invisible beam which has a terrible shape and is hard to focus?

 

[ru124t]

Have you ever seen the movie ghostbusters? You could build the batteries and cooling units into a proton pack like the one pictured below! It would not be handheld but it would be a backpack unit ! I ain't afraid of no ghost !

 

[vortish]

You could do it i think if you used a cryonic solution such a liquid nitrogen or some thing similar. but you run into another issue wearing a tank of a cryonic solution in it self is stupid.. 100w in anything man portable is beyond idiotic.. no one needs that kind of radiation producing item that is portable... you have to think of it on these terms.. yes a standard halogen is 60 to a 100 watts but that is coming out of a 120 v outlet.. i dont remember the amps but a standard 120 outlet can kill you.. so you want to put that kind of power in a packpack and you end up with a short then your going to be in trouble.. I would forget this idea

 

[ru124t]

Hmmm, we could always use a quad and haul it around in a cart towed behind it! That would be some serious atv! Deer hunting with lasers just watch out you don't burn down the forest!

 

[rhd]

Ok, so lots of nah-sayers here, but as someone who is a big fan of pushing the limits of miniaturization (like this, or sneak peak, this), I think the forum is just lacking creativity To your credit, you did say "I would probably only power for like 3s max".

Driver-wise, you're just not going to find something pre-made that can handle your task, in a form factor small enough for portable.

That said, it's easy enough to make your own linear driver. I'd suggest some variant of this:
LED driving and controlling methods
With an incredibly high-current MOSFET like this:
MOSFET N CH 40V 195A D2PAK-7PIN

I say "variant" because you want to get that 0.7V drop down a whole lot lower. 0.7V may not seem like a lot, but at 150A, that's over 100W of heat generated right there. If you can find a schematic for a good all-MOSFET driver, you'll be in good shape I think - as long as you don't mind doing your homework and working at it.

What's your source for the diode?

 

[deltawars]

Ok so i need a lower voltage battery.

3.7v Lithium Battery = 100 x 1.8 = 180W of heat.
2.4v Prototype Lithium Battery = 100 x 0.5 = 50W of heat.

I think I will make the diode pules for either 1s or 0.5s when I pull the trigger.
I'm going to do some more research on drivers now.

 

[ryansoh3]

Operating notes: De-ionized water is required.

Are you up to this?

 

[deltawars]

For cooling I want to use heatsinks and fans, maybe a TEC.
But I still have some task ahead, for instants I need a driver and lens to focus the beam, the battery was only one small part.

 

[DashApple]

I once used 20 LM371 regulators set to 1A each all in parallel to make a 20A CC source ,
Terrible efficiency but straight forward

Just use 100 of'em >

 

[rhd]

If you think using this battery is your solutIon: Lithium Titanate Battery
...then I think you've got a lot of reading / research to do before you tackle a project like this.

That battery makes no sense in my mind. At nominal voltage, it gives you what 0.5V of clearance? What's going to happen as soon as the cell is under a load? And what driver solution have you chosen that will work with such little clearance? If you depart from Lipo for a lower voltage cell, I think you'd at least want to sick to LiFePo4, at least until you've chosen your driver topology, and know that it can accommodate razor thin dropouts.

You still haven't answered the question re diode source. Do you have a source for this diode? If you don't, if you're just going by the fact that you saw it in Coherent's site, it would be nice to know that (because it makes it 10x less likely that you'll go through with this project that we're taking time to discuss with you if you haven't sourced, and more importantly, priced, the diode first)

 

[bostjan]

TE Modules aren't usually very good at dealing with tons of heat all at once, directly. I've tried using some pretty large ones to try to cool high temperature components before, and always burned them up. They can work as a component in a liquid heat transfer system quite well, though, but if you are trying to miniaturize, this won't really help.

But then, I've never played with a 100 W LD before, so maybe it will work. I would only advise to expect to burn a few of them up in the R&D, then potentially get a negative result.

 

[deltawars]

Do you have a source for this diode?

No I don't have a source I just assumed I could find it anywhere, but I have found a place where I can buy 40W diodes made by Coherent.
http://www.coherent.com/download/6631/Conduction-Cooled-Package-780-nm-830-nm-Data-Sheet.pdf

I have also found a place that sells 60W diodes but they don't say the manufacture, and they don't say the max voltage input.

I think I have found a solution to driving them but I'm still confused about the voltage.
I know that we run the diodes in our laser at higher current and voltage, but can I do the same with laser bar arrays, if it says 2v Max could I run it at say 2.6V, or would it kill the diode, if it can be run it at a higher voltage do I have to decrease current as I increases voltage?

 

[DashApple]

No I don't have a source I just assumed I could find it anywhere, but I have found a place where I can buy 40W diodes made by Coherent.
http://www.coherent.com/download/6631/Conduction-Cooled-Package-780-nm-830-nm-Data-Sheet.pdf

I have also found a place that sells 60W diodes but they don't say the manufacture, and they don't say the max voltage input.

I think I have found a solution to driving them but I'm still confused about the voltage.
I know that we run the diodes in our laser at higher current and voltage, but can I do the same with laser bar arrays, if it says 2v Max could I run it at say 2.6V, or would it kill the diode, if it can be run it at a higher voltage do I have to decrease current as I increases voltage?

Everyone would be doing it if they could be found " Anywhere "

There is no point in over running a diode like this power wise , if the diode is stated at its rated power at the recommended drive current , then you should run it at that . The 40W CCP 808nm is specked at <46 (42 typ.) so that would say you could drive the diode to 46A ( diodes safe max current ) and it would output over 40W , at around 42A it would output its rated power of 40W and drop around 2 Volts .

If you wanted to exceed the 46A maximum then you can , but you risk more charnce of damage as there are 19 emitters within quite a small space ( 10mm )

You don't run the diode based on it its voltage , you run it based on its current requirements , the voltage will change over the current range , but a small change in voltage could cause a large change in the current , that's why they are run with constant current drivers , Don't use a voltage source on a diode like this ..

The voltage across the diode is a function of the diode and the current passing though it , trying to increase the voltage ( above its max ) and decrease the current will just cause the power to drop and risk damage to the emitters , Where as in constant current the diode can be happily run , Power from a diode is mainly the function of the current passing though the die and the voltage is partly a function of the " band gap " the die has .

Running the diode from a voltage source would work ( 0 - 2 volts variable ) but you have no precise control over the current and as I said small change in voltage is a big change in current especially on these bigger diodes and you cant regulate both at the exacta same time .

long story short , run the diode it constant current at its recommended value .

 

[deltawars]

I know we run them at Constant Current and the current should not be more then the rating, but is it fine if the voltage is around 2.6V even though the datasheet says 1.9v Max?

And sorry for asking all these questions but this isn't cheap, the 60w diode is £200 alone, plus cooling fans are like £30 each and I need 2-3 of them, then there is the battery which is like £60-70, and that is without the heat sinks, driver, protection, custom lens assembly and the host.