New FOCUSABLE 200mW Red on DX

Yeah, mine gets really hot. This laser will pull the same current until your batteries are dead.

IgorT, do you think I might have messed up my measurements some how? (I can see myself doing something stupid ) I really need a regulated PSU to do some real measurements with this thing, but I am flat out broke at the moment.

My laser gets pretty warm too, I can't believe the components on this board are getting that hot!

potatorage said:

Yeah, mine gets really hot. This laser will pull the same current until your batteries are dead.

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Are you 100% sure of that? Because my tests don't agree. The slightest change in voltage produces a change in current.

This would not happen with a constant current driver, unless it was below the point of regulation. So unless we have different drivers, this doesn't make sense. There are always variances in components, and some can go lower (or higher) than others and still work, but not this much.

styropyro said:

IgorT, do you think I might have messed up my measurements some how? (I can see myself doing something stupid ) I really need a regulated PSU to do some real measurements with this thing, but I am flat out broke at the moment.

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No, i don't think you messed something up. It's just odd, that's all. It warrants more testing. The tests i did were with a PSU, because there i can simulate the battery losing voltage much faster. On a battery it would take longer to do the same.

When i have some time on my hands, i will do some testing on the batteries, and then i can tell you what to try, so we can compare our results.

styropyro said:

My laser gets pretty warm too, I can't believe the components on this board are getting that hot!

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Since the laser diode only consumes half of all the power coming from the batteries, and dissipates even less than that (since it shoots some out), the components have to dissipate the rest.

An LM317 actually dissipates more heat in a similar situation, since you need two 3.6V batteries, which have 8.4V when full.
The efficiency in the case of 317 with full batteries is actualy only 35%, so the other 65% get transformed into heat in the IC. But it's larger, so this is not as noticable.


I left my laser on for a couple of minutes yesterday, untill the tube was very hot (interestingly enough, the head itself never gets hot), and then i immediately took it appart, and measured the temperature on various components with a non contact IR thermometer.

The diode is the hottest part. It actually burned when i touched it. It measured 75°C, but since this dissipates quickly once it's OFF, it must have been more. The other components were at around 55-65°C by the time i measured them.


The diode is not really that small compared to a normal through hole diode, so i don't know what is making it so hot. Maybe it's being used above it's maximum ratings. Altho 310mA really shouldn't do that.



EDIT: Oh, and i just did a quick test on slightly discharged batteries, and the current was 280mA. The power was 150mW. It's definitely not a constant current driver. At least not in mine. If you can repeat your measurements, you should notice this very quickly, if yours is the same..

I wouldn't be surprised, if it wasn't. Differences in the same model of chinese lasers, ordered during a short period of time, have been noticed before..

Oh, and this laser is rated as 200mW, and the diode really does put out 200mW at 310mA, but that is before the optics.
8-9% losses in the optics bring this down to 175mW.

I hope i can get some imput from people, who measured 240mW (battery type 3V(green) or 3.6V(blue)? pot adjustment? current?)..

So i finished the lecture, so i figured, i might as well do some real testing on the laser...

I was sure it was not regulated, but i wanted to use 3.6V CR2s, so i decided to turn the pot down, connect it to 8V and slowly turn the pot untill the current was at around 330mA.

I turned the current down to 120mA at 6V input, and raised the voltage to 8V. I connected the laser again, and imagine my surprise, when the current was still 120mA. I tried lowering the voltage, and the current would stay constant down to 4V at 120mA. When i slowly adjusted the current to 330mA at 8V, i discovered, it can keep a constant current down to round 6.3V.


This thing really IS regulated. But since it's meant to work off two 3V cells, it drops out of regulation WAY too fast.

But this does NOT mean we can just put 3.6V CR2s in and expect it to be safe!



Since the manufacturer wants it to work off two 3V batteries, they adjust the pot untill they reach the desired current, which would seem to be 310-330mA. My laser can now work off two 3.6V and actually keep a constant current over their entire voltage range as they discharge.

BUT!

Had i just put in the 3.6V batteries, without first adjusting the current down, and then back up again, i would probably have blown the diode. My pot is set round 45° clock wise (lower), from where it was before. I have no idea what the current would be, if i left it where it was. I don't want to blow the diode just yet.

Of course the driver has to dissipate way more heat now, so it gets even hotter. I was holding it in my hand, and it burned my fingers. I don't know if the components have built in thermal shutdown. If it was just one regulator IC it probably would, but since it is several components, that do the regulating together, most of them don't. They could get damaged from all this heat.



Why some of yours can regulate off a lower voltage, i don't yet know for sure. Could be a different driver, or it could be component variances. Or maybe the difference is in the Vf of the diode. If the diode was removed, or soldered across the input in reverse, the Vf wouldn't affect the voltage the driver gets, and then mine could regulate off 6V for a while as well.


I really don't like how hot it is getting, so i'm gonna replace the driver with a 317 or even a buck regulator (to double the run time). I might test the max current the diode can take along the way, and then replace it with an open can.


Ok, i just raised the current to 360mA, and i got 186mW now. I don't know how much more current it can take. Dr_Lava said it looks like the Phazor diode. Could be true. Those are rated at 200mW and that is what this one is putting out at 310mA. If it really is a Phazor, it could probably take a little more than 360mA.

I would still like to know how some people got 240mW out of it. Was it perhaps with two 3.6V CR2s? That might make it regulate at the current it was actually set to. I marked that position on my pot. Might try it, but don't want to kill it yet.


I would not recommend turning the pot without measuring the current while doing so. While trying to adjust it to 360mA i overshot a couple of times. Luckily i limited the current on my PSU, so it prevented it from going any higher. The pot is VERY sensitive towards the low resistance side.

I accidentally pushed the voltage to 10.4V at one time, and the current remained the same.


So now i know this laser capable of working at a constant current, but since it's also meant to work from two primary cells, i'm not completelly sure putting in two 3.6V cells is safe for all of these.

Some of them would definitely remain in regulation, since they already do that at 6V. But for those, this would do nothing other than generate more heat.
Others might jump into regulation and kill the diode. The latter would probably do so, because the manufacturer doesn't really check if the regulation works (or they don't care to save money), but just set the current to the normal level. The end result being some lasers that can keep a constant current and others, that start at the same current, but drop with the battery voltage.


For now, i'm just going to test, how the driver can handle dissipating the extra power from two 3.6V CR2s.
When i'm done, i will turn the pot to the original setting, and power it on, to see what happens.


There is some info, that would help me a lot:
- Is anyone using blue 3.6V CR2s? If so, what is the current?
- Is anyone perhaps charging the green 3V CR2s at the 3.6V setting? (Up to 4.2V - this could explain some of the measurements)
- If you measured >200mW of power, please measure the current and share.

Thanks!

Mine died. I'm so pissed off.

potatorage said:

Mine died. I'm so pissed off.

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Ah, I'm sorry :'(


Also, just a question, does anyone know where to buy replacement lenses for this laser? Mine is really tattered, and doesn't have a clean beam..

Thanks

Yeah, i would also like to buy some replacement AR coated lenses. I just realized, that all my modules ordered directly from AixiZ came with clear lenses, and most of them are scratched up, or dusty, or would get scratched if i cleaned them.

When i put the Dilda lens in my 182mW red, i got 194mW out of it, just because of the AR coating.


Otherwise, Jeremy, you should be able to get them from AixiZ. Make sure you ask for 650nm AR coated lenses. Otherwise, they may send you clear ones, like they sent me, and your power will be lower, than with a coated one.

Ugh. I bought one of these from DX, and everything else shipped, but the laser is still "Pending." =_=

It's in high demand... This is the first time a red laser is available so cheaply.

And it's actually a nice laser.

UG0TB4NN3D said:

Ugh. I bought one of these from DX, and everything else shipped, but the laser is still "Pending." =_=

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Yep, thats what mine says too. Darn. I dont really want the charger and batteries yet if i havent got the laser. Haha, lots of use that is. Nevermind i guess i will just have to keep waiting.

I must have been lucky, as mine shipped almost immediately.

damn you igor! Hehe

chickenfish said:

damn you igor! Hehe

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Well, on the other hand, i don't seem to be able to get a non mode hopping green laser from there..

And when i force them to test one before shipping, then it doesn't mode hop, but also doesn't work with the batteries in the tube. : Too bad it doesn't work without batteries either..

I got a faulty greenie from DX and i'm getting like 30 bucks store credit, so i'm really looking at this as my second (if you count the week or two that the greenie worked) laser.
I'm aware of all the risks, which is why i'm looking for some cheap glasses to protect my eyes. i know that these don't have IR so i don't have to worry about that, but the glasses on DX are some of the cheapest i've seen, and they're almost as much as the laser itself. I saw a pair of bluray glasses for like 15 bucks in the deals section, is there anything that cheap for reds??

Is there anything else i should be aware of before buying one?