My new 1.5w laser build, by rhd

Today I received the laser I bought from a forum member, rhd (most of you all know him). It is a nice laser and my most powerful so far. I do have safety glasses and will respect this laser. He sent it to me with two 18350 3.7v ultra fire batteries. I'm hoping the laser diode will have a good life running at this power. I also have some Tenergy 3.3v CR123 batteries I can also use with it. I'm not sure what the output is using them but it is less as compared to the 18350 batteries.

Here is what rhd said before shipping the laser:


(I just setup your laser - decided to run it at 1,660 mA.

Just ran the raw output (no lens yet) into my LPM and hit 1,650 mW !

The lens will cut that down a little bit, but you're still going to get the (+) side of my 1.5W +/- 10% estimation!

I'll do a proper LPM run with the lens shortly. Just wanted to share the cool news!)

Here is a photo: look in this thread, fourth post down.
http://laserpointerforums.com/f65/who-builds-1w-445-sale-62651.html

The laser ended up having a peak of 1.58w, nice. I'm wondering if I should continue using the ultra fire batteries or run the laser at a lower power to extend the life? Either way it is strong enough. For those of you that have 1.5w 445nm lasers, what has your experience been with diode performance & life? If this one dies soon, rhd said there are plenty of you on this forum that could replace it for me. I'll post some photos soon.

Todd

Glad you're enjoying the laser! I'll toss in some more techy details to help others provide feedback on your question here:

It's a 1085 based driver, with the IC thermal epoxied to the main heatsink. It's using a 0.75 ohm 3W current set resistor. It's a silver guidesman host, with the usual sized guidesman heatsink. (not sure if this was Moh or Ray's vintage). Input and output caps, both ceramic.

And also, if you don't mind, I want to add a clarifying detail, just because I don't want anyone to misunderstand. That quote mentions a raw LPM output figure (no lens). I think it's important to clarify that after the initial raw LPM reading, I DID go back and do a normal "with lens" (ie, not raw) LPM reading for him before I sent the laser off, and that was the second figure he mentioned (1.58W).

I only mention that ^ so that it's clear to everyone that I wasn't selling a laser just based on the raw reading. I just happened to have measured the raw output first That's important, since most lasers are sold based on with-lens readings (which are always a bit lower than raw readings), and I don't want anyone to get the impression that I was trying to squeeze out extra mW in the way I presented/worded the figures

Thanks rhd for adding that extra info, sorry if I misconstrued your technical data. I also want to add that the work of rhd is excellent! Nice and clean finish to his products/builds. Thanks for the great laser rhd! I love it!

Todd

I'm curious to see what people say here. Basically, what happens when you run it off the Tenergy's, is that the voltage available to the LD after driver dropout will probably be lower than what the LD's PIV curve indicates it would actually need as a Vf at the current of 1660. So this acts to effectively lower the actual current your LD consumes.

So with your lower voltage Tenergys, you'll probably be running the laser at less than the 1.5W of output power that you'll see with the lithium ion 18350s.

Now, it's a bit tough to know how much less (can you estimate visually?)

My theory (but I might be wrong) is that a laser running at 1.5W would have a roughly similar life span as if you ran it lower at 1.2W, assuming you observed a shorter duty cycle when at full current, as compared to when at lower current. IE, as long as the max heat is the same at both currents (because you adjust the duty cycles), I would think that LD life should be comparable.

However, this is totally unsupported. Just my hypothesis. I'm interested to see if anyone has better input than mine on this subject.

Ok, well as for a visual inspection and burn test, the Tenergy batteries run the laser at an output that is still stronger than the WL Arctic (beam and spot are visibly brighter). The CR 123's also allow the custom laser to burn much faster than the arctic (arctic takes 2 seconds to start smoking wood, the custom laser burns nearly instantly (using unfocused beams or focused to infinity and not focused to a spot). When the LI 18350 batteries are used, the beam and spot are brighter still, and burning is instant! So I can say that the Tenergy batteries are used seems to be somewhere between the arctic and 1.5w, my best guess is 1000~1100mW, similar to the Spartan laser.

Todd

Ahhh - totally wrong on what I thought was happening here. If your tenergys are like these:
Tenergy LiFePO4 RCR123A 3.0V (3.2V) 750mAh Rechargeable Battery

Then they actually have a really low (550A) max safe discharge rate. In which case, I would actually recommend not using them, since the driver will actually pull (or try) more current than they can safely supply. That's probably not great for your batteries, or for your batteries' safety.

So they're dimmer, not because of voltage or PIV curves, but just because the current the driver wants to pull is so much higher than what the batteries can safely supply. So while the longevity question is an interesting one, I think there are compelling reasons to stick to the lithium ions.

thats a great lookin host, nice laser, rhd has helped me on alot of problems, and quesstions.

rhd said:

Ahhh - totally wrong on what I thought was happening here. If your tenergys are like these:
Tenergy LiFePO4 RCR123A 3.0V (3.2V) 750mAh Rechargeable Battery

Then they actually have a really low (550A) max safe discharge rate. In which case, I would actually recommend not using them, since the driver will actually pull (or try) more current than they can safely supply. That's probably not great for your batteries, or for your batteries' safety.

So they're dimmer, not because of voltage or PIV curves, but just because the current the driver wants to pull is so much higher than what the batteries can safely supply. So while the longevity question is an interesting one, I think there are compelling reasons to stick to the lithium ions.

Click to expand...

Thanks for pointing that out RHD. I've tried these batteries in nearly all my builds with no problems so far, but I wouldn't want to risk a problem.

Nice laser BTW.