532nm operating temperature

I have heard a few versions. Some people/companies say 10-35 degrees, other say 20-40. What is it now? Or cant we aay its a certain range cause every laser is build differently. Are people having issues at 10 degrees? I live in Switzerland.

532nm should be fine unless it's super cold or super hot. Probably won't be an issue at 10 degrees Celsius which works out to 50 degrees Fahrenheit.

It mostly depends on the KTP crystal, and how it was cut. Because it's such a low-quality crystal (in the case of eBay pens and such) the optimal operating temperature seems to fluctuate quite a bit.

I've had countless green pens, and while most operate best at room temperature, I've had a few that needed to be warmed up or cooled down a bit before they would be operating at full power. It really just depends on the laser you have.

I start having regular noticeable issues around 7 C. In Colorado where I have most of my star parties, I literally can't get a 532nm to work below 4 C without warming it up periodically. Mine are low quality though, so I assume you could do at least a bit better with something nicer.

Edit: To be fair, the battery voltage and internal resistance will be somewhat affected at such a low temp as well. Depending upon the driver and battery combo, that could also stop a cheapo from working.

Generally most KTP are cut to the desired wavelength, and the KTP lattice expansion is most efficient at around 23C but not always.

Thanks for all the answers!

Hey guys!


Just got a Laserbtb PL 532 300mW today and I dont know which battery I should buy. I tried out my laser with this battery:

Nitecore 18650 3.7V 2A 9.6Wh 2600mAh Protected Li-ion Rechargeable Battery-Black+Yellow(NL186)

Amazon.com: Nitecore 18650 3.7V 2A 9.6Wh 2600mAh Protected Li-ion Rechargeable Battery-Black+Yellow(NL186): Sports & Outdoors


I usually use this battery for my headlamp. The laser was really weak, couldnt even light a match. So that probably means it's the wrong batteries right? Which ones are the best to maximize the power of my laser?



Also are those red glasses enough to protect my eyes or should I get those eagle pair glasses?



Thanks in advance and best regards! any help would be greatly appreciated.




Would those batteries work?


Panasonic NCR18650B_1 18650 Li-Ion Akku: Amazon.de: Elektronik


18650 battery unprotected | eBay

2 Sony VTC4 30A 3 7V 2100 mAh High Drain 18650 Unprotected Batteries | eBay

2pcs Panasonic NCR18650PF 3 6V 2900mAh 10A Rechargeable Battery Unprotected | eBay

2 New Efest 18650 1600mAh Unprotected 30A Batteries Flat Top | eBay


really need help with that

And by the way: Why was my laser not able to burn that match? I thought 300 mw is enough?

Nitecore makes good batteries if u not able burn with a 300mW laser then its something very wrong, even a 100mW if u focus right will burn a little.

I believe that unit takes a single 18650 and if you have a really weak beam something is very wrong like Mortuss said. Is the battery fully charged? Is the lens cover fully open? Where did you buy it from as in person or right from them? Are you using it in a really cold environment or is it room temperature? Don't like the sound of this....

Check that the lens cover is fully open.
Check that the battery is fully charged. (An unprotected high drain 18650 is best.)
Check that the connector in tailcap is inserted fully.
Check that that the power button is fully pressed down/clicked down. (I've noticed they are very temperamental with some models.)

Aside from that, 300mW, when focused should definitely be able to light a match.

InfinitusEquitas said:

Check that the lens cover is fully open.
Check that the battery is fully charged. (An unprotected high drain 18650 is best.)
Check that the connector in tailcap is inserted fully.
Check that that the power button is fully pressed down/clicked down. (I've noticed they are very temperamental with some models.)

Aside from that, 300mW, when focused should definitely be able to light a match.

Click to expand...

Check that the connector in tailcap is inserted fully. --> About that: I can't insert it fully into my laser. Is this the case cause I am not using a flat top battery (as suggested) but rather one with a bump?

What are the consequences of a non fully inserted tailcap?

I'm assuming we are talking about the tail cap with the pin. You can get them without the pin/mono jack or you used to be able too. I would like to see what you mean when you say you can't get it all the way in. It should push in just like any headphone jack. You can bypass that by just taking a piece of wire and touching the battery end to the bare threads of the host to see if that is actually an issue.
As always, pics go a long way to show what you think may be wrong.
There were some issues with the front sticker at the aperture where it was partially covering the hole and all you had to do was cut around the hole with a razor to fix it but I think that would be enharently obvious if you have very low output. What about answering the other questions please. Help us help you We could list a huge number of potential issues each one being less and less likely but there's no point without checking the basics first.

InfinitusEquitas said:

Check that the lens cover is fully open.
Check that the battery is fully charged. (An unprotected high drain 18650 is best.)
Check that the connector in tailcap is inserted fully.
Check that that the power button is fully pressed down/clicked down. (I've noticed they are very temperamental with some models.)

Aside from that, 300mW, when focused should definitely be able to light a match.

Click to expand...

What is my noobie brain missing on this? BotoX had said on another thread of this regarding this same laser that he got the laser to burn very well and didn't realize he had to focus it.
Is it about getting the battery to fit now?:thinking: