Kaidomain 50mW CR2 - inital review

[knimrod]

Re-charging a primary lithium cell? At the very least, i'd suggest better eye protection than you would use for using the laser

417 mA sounds like a lot to mee to, mine draws around 300 mA from a fresh rechargeable. I can't measure output power, but i'd say it's pretty close to the claimed 50 mW from the rechargeable. From the primary it's a bit less, somehow laser manufacturers can't seem to create a decent current source. This still surprises me, it's not that hard to get it right, especially when you -can- get the rest of a DPSS laser right.

It's not an ideal solution for sure but it's only temporary while waiting for some 3V rechargable CR2s I 've ordered from DX. I have plenty of experience charging lithium batteries used in various RC aircraft so I'm careful.

I completely agree about the design of the control electronics..

 

[knimrod]

Re: Kaidomain 50mW CR2 - initial review

I bought and received another one of these from KD and it arrived DOA.  This will probably be my last purchase from them because I'm tired of returning their defective lasers.  I was going to send this back but decided I would further my education by attempting a repair.

I did try my 3.6V rechargable CR2 battery before disassembly and it actually produced a weak beam which lasted for all of about 5 seconds before fading out completely.

Taking apart the optics assembly was kind of messy since everything was glued together and there was this sticky, syrupy stuff all over everything.... like epoxy that wasn't mixed properly.  I managed to remove the lens from the YAG/KTP assembly and the YAG/KTP assembly from the diode assembly.  Powering up the diode without the YAG/KTP made a dim red glow at 250mA and pointing the output (close) at my power meter only registered about 16mW.  Pushing the current to 300mA didn't do much and pushing it to 400mA picked up the power to about 25mW and a very warm diode module.  I think it safe to say the pump diode is dead.  

The pump diode is an open can, 5.6mm package.  Can I buy a replacement diode for a reasonable price anywhere?  I assume this should be a 150-200mW diode for a 50mW rated laser?

 

[Benm]

Even if you could replace the pump, it might be worth figuring out what killed it first. Might be a doa diode, but could also be electrical malfunction or even optical trouble (reflections back into it).

If you do replace the pump, bear in mind that the pumping wavelength is something that has a rather narrow range. Just a nanometer off the intended 808 will probably result in a big drop in performance. Since there is no thermal control in these units that can tune the wavelength, i guess it's a matter of luck (which is also why many of these pointers have problems with warm and/or cold operation).

 

[Hemlock_Mike]

I've been using a TR15270 Ultrafire 3 volt in mine for months.  The paint is wearing off the housing.  Runs about 45 mW.

Mike

 

[IgorT]

So, has anyone figured out which one is better yet? The DX30 mW or the Kai 50mW?


Also, can anyone tell me how visible the green beam looks, compared to a red DVD burner at 150mW? Since we see green light better, they could be very close, right? I don't care about any burning powers, just the visibility..

 

[IgorT]

I'm using 3.0 volr CR2 rechargeables.

Hi Mike!


So 3V rechargable lithiums actually exist? I was confused, because on several shops, they classify them as 3.6V and the picture of the battery says 3V.. When i ask them about this, they simply don't know the answer..


How much does a 3V rechargable measure, when it's fully charged?


Thanks!

 

[nikokapo]

what about some beam pics

 

[Curiously_Coherent]

My KD-50 has been great and works wonderfully with rechargeable Lithium CR2s (DX SKU#932). I use The UltraFire 3.0V/3.6V CR123A Charger (DX SKU#1236) because I have other lights that use CR123As. I use spacers to charge the CR2s (Rare-Earth magnets (DX SKU#5962) and make sure to switch the charger to 3v before I plug it in. The CR2s come out of the charger at 3.4v and give a nice bright visible beam. I have hours on them now and the diode's fine.

The beam is a lot brighter than my Pulsar 125, even in fog. Yes, the eye sees green much better. If visibility is what you want, green is your colour.

Cheers, CC

 

[IgorT]

The beam is a lot brighter than my Pulsar 125, even in fog. Yes, the eye sees green much better.  If visibility is what you want, green is your colour.

Wow!

Someone actually answered all my questions at once.. Doesn't happen often enough. Thanks!
So the rechargables actualy do come in 3V and 3.6V.. That's good to know, because the shops selling them often don't know this.


Some people here said that when they use a 3.6V rechargable, the beam actually gets even brighter. So the circuit inside isn't regulated at all? What does that IC do then?


I think i'll buy one and add my own buck regulator with a RCR2 at 3.6V, to keep it at the optimal voltage through the entire battery voltage range as it discharges...

 

[IgorT]

I just noticed, that UltraFire batteries at DX cost almost half the price of the same battery in UltraFire's own shop..

Unfortunatelly i can not find 3.6V RCR2 at DX, only the 3V version... Does anyone know if they have the 3.6V version as well? It's kinda hard to find anything, because they don't name them this way..

 

[knimrod]

I got my 3.6V rechargable CR2s from a Hong Kong Ebay seller. They are marked "Ultrafire LC 15266 600mAh 3.6V".

I don't recommend them in this laser however, With one of these installed in mine, the current was 417mA. That's a bit too much IMHO.

 

[Benm]

That's odd, i run mine from 3.6v rechargeables all the time, and it's still fine. However, current draw is only around 300 mA with that voltage on my unit... quite a big difference between units if you ask me.

 

[IgorT]

That's odd, i run mine from 3.6v rechargeables all the time, and it's still fine. However, current draw is only around 300 mA with that voltage on my unit... quite a big difference between units if you ask me.

That is weird. More than 100mA difference between two lasers at the same voltage?

But this thing doesn't seem to be regulated all too much anyway, so maybe the internal resistance of the batteries has something to do with it as well.


But i was thinking of using a rechargable + a LM3410 buck converter, to regulate the voltage to a safe level, or even limit the current if necessary.

 

[Benm]

I guess that would be double then, but it might help stabilize power. Otherwise, you could simple wire a diode in series to create a 0.7v additional drop, presenting ~3.0 volts to the driver from a rechargeable.

 

[joenobody]

.
     
Hey There,

So if the protection diode is in series prior to the elctronics, it is producing the 0.7+/- volt drop and should work out great to drop off the extra voltage from the rechargable. (and the waste shouldn't be that great on the battery?)
                                           :
Then couldn't you put a diode back in parrallel at the laser diode to regain protection to the LD like in the DIY drivers? As diode protection in parrallel will have no, or negledgeable effects on voltage/crruent.
                                  (did I spell that right?)
Please feel free to yell at me if I got that wrong?  ;D

Thanks!
 Joe
   [smiley=thumbsup.gif]

 

[knimrod]

That's odd, i run mine from 3.6v rechargeables all the time, and it's still fine. However, current draw is only around 300 mA with that voltage on my unit... quite a big difference between units if you ask me.

Maybe so but it would explain the many reports of lasers being rendered inoperable while using the 3.6V rechargables which are usually >4V off the charger....

FWIW, mine draws 298mA from a not-so-fresh 3V rechargable at about 3.2-3.3V.