GGW-H20L 6x Sled GB!!! THE EPIC GB THREAD LAWL!!!

[hydrogenman15]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Umm, the voltage does not matter, as long as you give the driver what it needs. The supply voltage to the driver under load has to be more than the driver's minimum input voltage.

If you do give the driver the voltage it needs, it will regulate the current by giving the load just enough voltage for the desired current to flow, and adjust this voltage, in order to keep the current constant. You can change the input voltage, and as long as it is within the driver's input range, the output voltage will not depend on the input voltage in any way - it will always be exactly what the load needs for the current you set.

If you give the driver too little voltage, things become dangerous! You may think the diode current is 200mA, but in reality, your dummy may have a lower Vf than the actual diode. Because the dummy has a lower Vf, the driver was able to regulate the current through it. But as you then switch to the actual load with a higher Vf, the driver will not be able to regulate the current through it! This is where things become interesting. As the diode works (at a lower current, than you think it works at), it slowly warms up. It's Vf drops, and as it drops, the driver can suddenly pass more current through it! After this it warms up faster from more current, and passes even more current, and theoretically, it could drop in Vf enough for the driver to start regulating the current. Or it could just climb towards the current that is actually set.

The really dangerous part is this: If you "set" (or rather think you set) the current through a dummy when the driver does not get enough voltage even to regulate the current even through the dummy, the current you see on the meter will be lower than what you actually set the driver to. As you then connect the diode to the driver, thinking that the current is where you want it, the driver will try to do it's best, but the voltage will just not be enough. If you then suddenly do give it enough voltage, the current will shoot up to where it is actually set to!


A driver out of regulation with the Vf dropping with heat, allowing more current to flow, could explain the power climbing. As could a combination of this and the wrong current setting made with a driver out of regulation.


This is why i asked you how sure you were of your current. Do you really know if it was 200mA? Was it 200mA from the start, or did it climb there as the diode heated up? Could it have been set higher (set outside of regulation)?


This is why it is VERY important to verify that the voltage is in the right range when dummy loading. If you set a constant current driver under the right conditions, the current will always be the same. If you set the driver under the wrong conditions, the current could actually be set much higher.

But you can test this, if you haven't changed the driver setting yet. Put a dummy load on the driver, and measure the current. Then make sure the driver is getting what it needs (whatever that is, different for every driver, with linear drivers it depends on the load).



To simplify: When you gave the driver 5V, the current was not 200mA. When you gave the driver the right voltage, the current was 200mA (if it was set correctly, under the right circumstances).

This could be the reason for your diode being dead. So it is quite important to set everything up correctly, or at least to figure out what happened, or the data is useless. If your power changes with the drier input voltage, then you're doing something wrong - the current is not what you think it is.
If you haven't turned the pot yet, test the driver on a dummy with a high enough input voltage. It probably is 200mA, and the climb was just from a funky diode, but it would be good to know for sure.

Is it safe to put a 25 in series with a preset rkcstr driver so I can dial it up and at least give me some kind of power adjustment.

--hydro15

 

[IgorT]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Is it safe to put a 25 in series with a preset rkcstr driver so I can dial it up and at least give me some kind of power adjustment.

If you put a resistor in series with the output of a constant current source, the current stays the same. The only difference is, the minimum voltage required for regulation will be higher, because the driver will then put out a voltage, that will make the set current flow through the resistor and the diode.

A constant current source will put out the same current through any load, as long as the voltage required to cause that current is within the driver's output capabilities.


Putting a resistor in parallel with the output can bypass some current, but it's not nearly precise.

If you have a driver, the only right thing to do is to change the sense resistor, and set it to a different current.

 

[BluRay]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Got mine today also, thanks AMK


Also i noticed you havent updated my 4 sleds that i paid in batch 3. Can you put me down for batch 3 or if not just add me to batch 4. thanks



Tommy

 

[styropyro]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

[quote author=styropyro link=1223438970/660#679 date=1225767100]I was sick of waiting for my flexdrive to come so I hooked up my 4x to 167mA. Here's a pic of the awesome color, sorry about the quality, I had to use my cell to bring out the color. It burns nicely.

Glad to to see you got your 4x working. I practiced on the IR diode and I think I found a really good way to remove the diode with any visable damage. I still have not touched the red or BR diode though.

--hydro15[/quote]
What method do you use to get your diodes out? I just use a hacksaw.

 

[carulli]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

what are you guys driving these at, do you think 190ma is ok?

 

[jake21]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

i think 190 is good mine is at 200ma

 

[thesk8nmidget]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

you will need a duty cycle at that current. but yeeah it may last for a good amount of time with a duty cycle

 

[carulli]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

what sort of duty cycle would i need, 30s on 1min off? i will being using a pocketpal host with a heat sink (like jayrobs)

 

[hydrogenman15]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

[quote author=hydrogenman15 link=1223438970/680#687 date=1225838263][quote author=styropyro link=1223438970/660#679 date=1225767100]I was sick of waiting for my flexdrive to come so I hooked up my 4x to 167mA. Here's a pic of the awesome color, sorry about the quality, I had to use my cell to bring out the color. It burns nicely.

Glad to to see you got your 4x working. I practiced on the IR diode and I think I found a really good way to remove the diode with any visable damage. I still have not touched the red or BR diode though.

--hydro15[/quote]
What method do you use to get your diodes out? I just use a hacksaw.[/quote]
It was a really funky method but the IR diode was very well protected from any damage.

I knew going into this that the material was not brittle enough to snap and a hacksaw was just asking for trouble.

I secured one side of the heat sink and carefully bent the other side in the direction of the lens with pliers. When doing this
I was surprised to find that the metal holding the diode in place had been warped to such a degree that the diode was getting loose, although it was not loose enough to remove it. Then I
used the vice to push the warped sides of the heat sink back towards the diode and at that cause the other sides to get warped and the diode was pretty easy to get out.

Its kind of hard to explain but your basically stretching and warping the heat sink until the diode is no longer under any pressure. If your not careful you could warp the diode and that would not be good. I have not taken any of the other diodes out of the heat sink so I can't say for sure if its gonna work other two but I know it worked for the IR diode.

--hydro15

 

[IgorT]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

you will need a duty cycle at that current. but yeeah it may last for a good amount of time with a duty cycle

There is no duty cycle monster! It's all in your head!

If a diode dies it's from it's own optical output, not from being eaten by the duty cycle.


Duty cycle is only for diodes that are insufficiently heatsinked. If you use one of Jayrob's heatsink, it gives you a practically unlimited duty cycle.
If it then dies, it's because of too much power, not too little duty cycle.

Duty cycle can make over-overdriven diodes live longer in days, even months, but not in hours.


Normal diodes drop in power as they heat up, so the optical "pressure" decreases. If they have a sufficient heatsink, there will be only a small temperature increase, and a small power drop, and then they stabilise. This is also the reason why a diode can survive more current when hot, while it can die at the same current when it's cold - the efficiency, and with it the power is higher, when cold, at the same current.

But there are weird diodes, that climb in power with heat. With those, a small temperature climb can cause a huge power climb, and they can kill themselves. With those, duty cycle could actually help. But you shouldn't put a laser like that in your pocket.

That's why i'm praying, that with 4x's the heat related efficiency increase is just as rare as with the PHRs.


There is also another reason diodes are dying. And i can barelly believe it myself.

 

[carulli]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

thanks igor, so what are you driving yours at?

 

[IgorT]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

I will drive them so that the raw output (before the lens) is bellow 210mW. I don't want to push them CW above their pulsed ratings!

And i have something here, that will allow me to measure the raw power. Or at least as close as it gets...

 

[danq]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Updated Red Diode data from these sleds - with an Aixiz glass lense.

All measurements with the lense were made using only an Aixiz housing in a vise-grips for heatsinking (heat xfer isn't all that great there). For power I was using a bench current-regulated supply (that I built).

This is [was] a very tough LD. I had it up around 700ma for about 30 seconds, 5-6 times. Then after getting the current/power data, I took it up to a full amp of current - twice more. Briefly - it was not stable there. On the second shot, I saw the output power going down, then tried to bring the current down but did not react quickly enough, and lost it. But that was one heck of a laser diode!!

Oh, almost forgot: this diode was horribly mangled in extracting it a few days ago; and today I did it worse while getting the mangled heat-sink all the way off. The case was dented, and some small thing was rattling around inside - glass probably from the window. And then, while putting it in the vise-grips, I dropped the diode in the housing, about 3 feet onto a hard wood floor. Then I did the power tests.

One of these days I've got to move on to the blu-ray part of my sled!

 

[hydrogenman15]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

[quote author=hydrogenman15 link=1223438970/680#688 date=1225839037]Is it safe to put a 25 in series with a preset rkcstr driver so I can dial it up and at least give me some kind of power adjustment.

If you put a resistor in series with the output of a constant current source, the current stays the same. The only difference is, the minimum voltage required for regulation will be higher, because the driver will then put out a voltage, that will make the set current flow through the resistor and the diode.

A constant current source will put out the same current through any load, as long as the voltage required to cause that current is within the driver's output capabilities.


Putting a resistor in parallel with the output can bypass some current, but it's not nearly precise.

If you have a driver, the only right thing to do is to change the sense resistor, and set it to a different current.[/quote]


Oh sorry, I was talking about put in front of the input not the output.

--hydro15

 

[amkdeath]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Got mine today also, thanks AMK


Also i noticed you havent updated my 4 sleds that i paid in batch 3. Can you put me down for batch 3 or if not just add me to batch 4. thanks



Tommy

PATIENCE MAN!! I AM NOT ON HERE ALL THE TIME...

You pay on 11-3-08, and on 11-5-08 you file a dispute with paypal. All I can say is What the F***??!?!?!

What is the dispute for?? Item Not received? Not put on list yet? I dont get it...


and to all of these who "cannot read 36 pages" or "have lives", read the first page. EVERYTHING you need to know is on there. EVERYTHING. I was not accepting new orders for batch 3 (as it says on the first first post), but those who have paid anyways will be included.

 

[lasersbee]

Re: 6x Blu-ray SLEDS GB! THEY ARE GOING FAST!

Whoa... Chill... Take a pill AMK.. relax... tomorrow is another day

I know it's a bear keeping track of all the paperwork... who paid when...
when what is shipped... what needs to be ordered... Blah... Blah... and a
Zillion other things...

But don't get mad at buyers... that may not know the effort you need to put in
and the stress involved in a GB....
Just my $0.02 to help you cool you off... a bit at least ;D

Jerry