8X Diode Murder fund

pseudolobster said:

I dunno.... I've run my 8x at 300mA for a solid two minutes without any noticeable temperature change in the heatsink (a jayrob "sidebutton" heatsink), it still felt cool to the touch... My LM1117T and its resistors, however, were far too hot to touch (granted, I was running it off 12v)... A SF-AW210 diode running at 200mA for a solid 60 seconds with no heatsink other than the aixiz head only started to get warm, not hot...
As far as I can tell, bluray diodes don't generate much heat. On the other hand, a 16x red diode running at 300mA, or a LPC-815 LOC running at 400mA tends to get really hot in under a minute.

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Yep... I've got an 8X in a tiny Pocket Mini and it's fine.

There are plenty of kits with a much more massive heatsink than a Pocket Mini. The 12 X can't be that much more heat. It's not like were going to run them for 10 minutes at a time.

Igor's got an efficient blu-ray driver that will not be a heat issue for the driver, and Dr. Lava is working on one as well...

jayrob said:

Yep... I've got an 8X in a tiny Pocket Mini and it's fine.

There are plenty of kits with a much more massive heatsink than a Pocket Mini. The 12 X can't be that much more heat. It's not like were going to run them for 10 minutes at a time.

Igor's got an efficient blu-ray driver that will not be a heat issue for the driver, and Dr. Lava is working on one as well...

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Hearing that has made me

pseudolobster said:

I dunno.... I've run my 8x at 300mA for a solid two minutes without any noticeable temperature change in the heatsink (a jayrob "sidebutton" heatsink), it still felt cool to the touch... My LM1117T and its resistors, however, were far too hot to touch (granted, I was running it off 12v)... A SF-AW210 diode running at 200mA for a solid 60 seconds with no heatsink other than the aixiz head only started to get warm, not hot...
As far as I can tell, bluray diodes don't generate much heat. On the other hand, a 16x red diode running at 300mA, or a LPC-815 LOC running at 400mA tends to get really hot in under a minute.

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8X - 300ma X 5 volts ~= 1.5 watts

That heat is definitely heating up the diode in your light.

Blu-Rays generate more heat for the same current,
since the voltage is 67% higher (5 vs. 3).

Short run times won't show the heat rise.

LarryDFW

LarryDFW said:

The hosts used by many ARE too small for the heat dissipation of these more powerful diodes.

I was running some tests tonight with a very large 14oz. host:

This host heatsink was too hot to touch after about 10 minutes of continuous run time dissipating 2 watts.

LarryDFW

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2 watts??

What were you using for that test? A P7 emitter?




Here's some quotes from Igor on testing my tiny Key Chain CR2 for heatsinking ability. He used an open can at 500mA's to get close to the same heat as an 8X at 300mA's...

IgorT said:

Since i received two of these CR2 Keychain kits yesterday, i started thinking which diodes to put in them...

Obviously i'd love to have a very tiny 8x, but an 8x at 300mA is powered by 1.68W of electrical power, and produces 1.28W of heat. I wanted to make sure the build is capable of dissipating that for long enough first, since i'm not a big fan of counting in my head while using a laser...

... For heatsink testing i put a low efficiency LOC inside, pushed to 500mA - to kill it, and to see how stable the power is (= efficiency of heatsinking).
A LOC at 500mA also produces 1.2W of heat..


… Otherwise i left the test laser run for 30-60 minutes several times, and while it was "hot" (in human terms) at the end, the diode was still happily cool, at half the temperature it is made to work at...

So with normal use, the design is perfect as it is.


P.S. Only problem, the damned open can just won't die!!!
Perhaps i need to set it to 600mA...

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Here's Dave's impression of an 8X build in my Key Chain CR2...

daguin said:

It took me a couple of days to get to it, but here it is.

A couple of days ago I purchased this Jayrob "Key Chain CR2 Kit", used from DarkArmyofOne. I was busy yesterday and the day before so I couldn't get to it.

This morning I built it. I might not recommend it as a first build, but it is not as scary as it looks. The assembly was straight forward and followed JayRob's tutorial very well. I added a bit of electrical tape around the driver to help isolate it, but that is about the only thing I changed.

It took me about a hour this morning to get it done. It feels solid in my hand. With the focus ring adapter, focusing is fast and accurate.

It has an LG BH08LS20 diode in it (8X). It, of course, uses the flexdrive. I have some rechargeable CR2 batteries and am using one in this build.

The flexdrive is set at 370mA. The laser is putting out 440mW with the 405-G-1 lens. With 60 second burns the head gets to about body temperature. Body temperature is NOTHING to these diodes. With 30 second burns, it doesn't warm up at all.

Once again, Jayrob has built us up a winner!

Thanks JayRob

Now -- What do I do with it? :angel:

Peace,
dave

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This is just a tiny Key Chain CR2! See pictures of the tiny heatsink:
http://laserpointerforums.com/f39/fs-key-chain-cr2-kit-schweet-42773.html

I have kits with much more massive heatsinks!

I don't think were at the point to have to worry about different kits for even a 12X diode. We need new drivers yes, but Igor already has that handled, and Dr. Lava is also working on them as well...

LarryDFW said:

8X - 300ma X 5 volts ~= 1.5 watts

That heat is definitely heating up the diode in your light.

Blu-Rays generate more heat for the same current,
since the voltage is 67% higher (5 vs. 3).

Short run times won't show the heat rise.

LarryDFW

Click to expand...

420mA * 3v = 1.26W, with 300mW dissipated as light, almost a watt dissipated as heat..
300mA * 5v = 1.5W, with 500mW dissipated as light, a watt dissipated as heat...

In theory, I don't see how these require any larger heatsinks than we are used to... In practice, anecdotal evidence suggests these diodes are cooler and more efficient than reds... Numerous reports say bluray diodes generate less heat than they should, far less than a red diode...

Here's the heat sinking "in the sled" for normal use. I did not take the top off. It is left open like this in the drive



That little tiny piece of metal is simply glued onto the sled at four points.

Gone is the big heat sink over the rear of the diodes (like in the 6X)

It doesn't look like they are dissipating much heat in normal use. Yes we run them harder, but look at the treatment the red diode gets in the same sled. Completely surrounded by metal AND almost drowned in thermal paste.

Peace,
dave

Thank you guys for the reassurance. I have no doubts about my very own 8x now and the new 12x diodes. When I get the money, man this will be great. And thanks for offering to put it in a module for me Dave.

LarryDFW said:

The hosts used by many ARE too small for the heat dissipation of these more powerful diodes.

I was running some tests tonight with a very large 14oz. host:

This host heatsink was too hot to touch after about 10 minutes of continuous run time dissipating 2 watts.

LarryDFW

Click to expand...

that is not possible by just two watts from the diode. what driver and battery configuration are you using? i repeat, 2 watts is just laughable, by normal standards

manuel

Krutz;

I assure you it is possible.

I have been building UV LED lighting for several years.

2 watts will heat up a much better heatsink than we are using, very quickly.

Some of the drivers were 90% efficient.

The combination of high power laser diodes and small hosts will stress these components.

There is nothing wrong with small hosts.

You just need to limit small-host runtimes to a couple minutes.

LarryDFW

..actually a warm surface is a good sign, meaning the heat is getting away from the diode
well, you then have more experience than me! once any laser or led light gets seriously warm, i either dim it (light) or switch it off..
oh, holding it in your hand does its part too, of course, you transfer heat into your hand..

thanks for the info, larry!

manuel

Krutz said:

[igor]
dont forget that this is the first time we just use diodes from working drives! they were all tested good and reliable before selling. with sleds, they may be spares, rejects, prototypes or known bad diodes, who knows.. and, if i'm not wrong, all other diodes ever used were from sleds, be it LOC, PHR, 4x, 6x, or the stranger ones which we couldnt even identify..

Click to expand...

It's almost as if you were referring to the theory i proposed in another thread (i think FrancoRob's thread about the 8x i made for him), that the GGWs i got from the Chinese varied so much in everything from efficiency to wavelength (and sleds showed version progression), that i started thinking those sleds were prototyping rejects, and not really QC rejects..


But you are incorrect when saying, that this is the first time we are getting diodes from drives!

I got my first GGW from an LG 6x drive, as did MANY other members of this forum long before me!
GooeyGus was a serial GGW drive killer at that time already (and he extracted my first GGW for me)!

Before that, other members purchased 2x and 4x writers.. Jayrob still has one (either a 2x or a 4x from a writer - don't recall) in a laser...


I am not sure if i explained this here (too many threads open at once and too busy)..
- Diodes from so called QC Reject sleds (61 of which i plotted so far - in attachment) vary in efficiency from super freaks to many diodes so weak, that they could not possibly work in a 6x drive for ANY amount of time!
- Diodes from drives we have tested so far, always seem to have an efficiency i call "normal" (or average from the multiple plots), OR BETTER! In fact i define "normal" efficiency for GGWs by the first GGW i ever got - from a drive.. And funnily enough it turned out to be almost directly in the middle of the efficiency spread i found in sleds. I have not seen a low efficiency diode from a working drive yet!

The only way i could explain this incredible efficiency variation in sleds, and lack of it in drives was, that the sleds i was testing were prototyping rejects... Many of them were possibly even made while the diode manufacturer was still perfecting their manufacturing process (so they could consistently make good diodes), and they simply sent the sled manufacturers prototype diodes, so they could perfect the optics and do various tests, preparing everything for final manufacturing...



This is also the reason why i said i don't expect to get low efficiency 8x's from drives. I do expect efficiencies to vary - the first two diodes i tested varied almost by the maximum i've seen in other plots - but i expect even the lowest ones to be GOOD DIODES... Much unlike the low efficiency GGWs i found in sleds, which often die in a few hours when set to 190-200mA!



So yes, you are right, and i agree.. Diodes in drives HAVE to be thoroughly tested, first before even being sold to the sled manufacturer and then at multiple stages during sled/drive production. A bad diode would never pass the inspections...



If i did a 6x murder experiment similar to this one here using low efficiency (low for reject sleds, not drives) diodes, the experiment would be completelly useless. The diode would crap out in a few hours and wouldn't tell me anything about the "normals" or higher efficiency ones...


If you look at this multiple GGW sled plot, and now imagine the same plot was done by testing 61 GGW DRIVES instead, the plots would start at what i marked as average or normal, and only go up! (Obviously, drives would then have their own different averages, highs and lows..)


I am assuming all this of course, because it is impossible to make similar statistics with drives, but i am assuming it for good reasons..
For GGWs for example, i don't think any diode that measured in at less than 170mW @ 200mA could work in a drive! And in a drive i would not expect to find diodes with less than 180-185mW @ 200mA either.. (I'm talking about powers after plastic lenses here, and the plots were made with plastic lenses - the testing started quite a while ago)

If we were doing this experiment during the GGW times, killing two lowest efficiency GGW diodes from drives, we would likelly be killing one that peaked at 183mW and another at 187mW @ 200mA. It's unlikelly that it would be less.

And from experience i know those diodes are good, and survive a LONG time of abuse..


That's why i proposed to test the two lowest efficiency 8x diodes, because when it comes to drives, while some may seem "weaker" in comparison to the higher ones, they are all still very good, tough diodes...




Otherwise, i got a package today. An 8x diode from itw3ak i mentioned before - the one that developed the kink at the power it was set to... He gave it to me for the cost of shipping (THANK YOU itw3ak!)..

The 8x's from the mini-GB should also come this week. Need to finish work quickly, so i can start playing with them as soon as they arrive..

IgorT said:

The 8x's from the mini-GB should also come this week. Need to finish work quickly, so i can start playing with them as soon as they arrive..

Click to expand...

Yay! :yh:

Crazy Jay said:

Double the voltage. Multiple times the heat.

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No, double the voltage, same current = double the heat (if diode efficiency was identical.

Crazy Jay said:

These diodes are now the dominate ones on the market. Would it be correct to assume that the current hosts, sold on by members of this website, would not be suitable for these bluray's?

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No, that's not what i wanted to say. Actually i was more thinking out loud than anything..

Thing is, with previous diodes we started making smaller and smaller lasers. PHRs barelly needed heatsinking at powers they could survive, 6x's didn't produce much heat either (well, twice as much, but still not too much for even the smallest hosts).

We went as far as to make keychain LED light size 200mW lasers (and now more).. I have a 205mW Keychain in a host originally designed for three coin-cells. I often use it for 15 minutes straight (when taking beamshots), and while it feels warm to me, for a diode <40°C is far from overheating..

An 8x at 400mW on the other hand produces more heat than an open can red.. The 8x would get hot fast in the same tiny keychain..


An 1xAA or 1xCR123 host with a good heatsink can easily take care of an 8x for 20 minutes straight or more (still need to test exactly how long), a 12x won't be a problem either.

I'd be more worried with larger hosts, where multiple batteries and a linear driver are used! There the driver produces as much heat as the diode on top, sometimes more!


In any case, i didn't want to worry anyone, and when i said that i completelly forgot that most everyone uses a duty cycle. And for 1-2 minutes almost any metal mass will be enough.. Especially if the transfer to the host is good and you feel if it gets too warm.

With 8x's and 12x's in very tiny hosts, duty cycle would actually start becoming of some use..

IgorT said:

Before that, other members purchased 2x and 4x writers.. Jayrob still has one (either a 2x or a 4x from a writer - don't recall) in a laser...

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Pretty good memory Igor!

That was over a year and a half ago:
http://laserpointerforums.com/f38/blue-ray-dvd-writer-diode-harvest-20822-3.html#post335821

It was just at the same time (or just before) Dr. Lava and Hemlock Mike were bench testing GGW 6X drives...

I believe I was the first to build a blu-ray diode over 50mW's into a hand held laser using the 3405 host that I found and started making heatsinks for.

Anyway yes, it was a Sony BWU-100A 2X burner that cost me over $300 dollars. (actually $600, because I killed the first one) That same diode is still alive. (although it sits in the case mostly) I have since turned it up to 190mA's, and fit a 405-G-1 glass lens into a the (now modified) Meredith module. It is putting out 176mW's at that current. (keep sake laser)

wasn't people buying the xbox readers too to get the phrs? xD

Hallucynogenyc said:

wasn't people buying the xbox readers too to get the phrs? xD

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The XBOX 360 ADD-ON HD-DVD Players had the PHR-803T and the DT-0811 sleds

Peace,
dave