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Review: 1.4W 520nm Custom build

SteveT

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Overview

Here's a review of my custom 520nm Ehgemus and DTR special build. I have combined a 1400mw+ NDG7475 module from DTR with a powder-coated custom host from Ehgemus.

The host

This is a 2 x 18650 aluminium host with a sublime white powder coat. I worked with Ehgemus to confirm requirements and opted for a master tail switch coupled with a momentary side switch and a nicely machined focus adapter. It is a work of art.

I will let the pictures do the talking!







Specifications

- NICHIA NDG7475 520nm diode seated in 12mm copper module coupled with x-boost v7 driver (by Lazeerer) set at 2.4A.
- Estimated output power = 1400mw
- G2 lens with focus adapter
- Operating voltage = 6-9 VDC
- Tested with 2 x Sanyo 18650 Li-ion (2400mah) @ 8.29 VDC.
- Current draw at tail cap = 1.43A.
- Estimated run time on full charge = ~ 100 minutes
- Recommended max duty cycle = 120s on, 30s off.
- Beam divergence = 2.91 mrad.
- Beam diameter @ 2' = 2.08mm
- Beam diameter @ 13.75' = 12.51mm
- Relative Brightness = 675 lumens







Test and build pics

Assembly couldn't be simpler as the host came with a pre-wired contact board which was then soldered to the driver leads on the DTR module. (I tested polarity of the host before hooking the leads together).











Don't take any chances, wear an electrostatic wrist band to protect the sensitive diode from ESD.



My Thoughts

This is my favourite laser and build thus far. The brightness and intensity of this diode are awe inspiring and the pics don't even begin to do it justice. The beam characteristics are almost identical to the blue NDB7875 diode which means that it will easily be outdone by single mode and typical DPSS units when targeting distant objects. Nonetheless this build takes pride of place in my collection; an expensive diode warrants a special host so thanks again to DTR and Ehgemus!

Beam Shots

Excuse the mobile phone pics!











Comparison with my 100mw and 600mw 532s.



Thanks for reading!
 
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Alaskan

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Great, with that host, I'd love to have a 1+ watt 520nm laser! One of these days!
 

Shakenawake

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nice unit you have there. kinda tempts me for one, that extra ~400mW would be kinda sweet. I asked if my pro could be driven at spec, which I believe is 1.7A. with a diode that pricy I didnt have the guts to overdrive one. after the pro's optics mine does just under 1W. the nice thing is the Pro's expander which further reduces the power and widens the aperture beam but can bring it's divergence down quite considerably.

someone should send a jetlasers beam expander's adapter to Ehgemus to see if he could make a focus adapter to fit one on.

If I were you, I'd consider the following for future 9mm diodes, or anyone getting one made:

9mm diodes get hot pretty quick. their drivers tend to produce more current/heat as well. as such I recommend getting one encased in a module with the short back half or longer one with diode-back contact for better heat transfer. shown in the 4th and 27th post in the thread "best thermal pathway for heatsinks"

you could easily have DTR send Ehgemus the diode in such a setup as well as an appropriate driver and have Ehgemus make a host for them with a better fit. the driver could also be heat sinked better this way.

I only mention it because I have had high powered, whole module builds like yours have their drivers overheat and the output begin to flash, and have lost enough diodes that I want to protect them the best I can.

I also prefer constant on over momentary, though Ehgemus seems to like the momentary ones. pros have both, one good thing about them

have some rep
 
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SteveT

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@Alaskan

Thanks for the compliment; it's a nice unit but agree the divergence isn't a strong point!

@Shakenawake

Appreciate the kind words, advice and rep. I actually preferred a momentary switch in this instance as all my other units use a latching switch. In terms of heat transfer I am only running this for 40s at a time max which should help preserve driver and diode; the heatsink is warm to the touch after this (28C)

I would be interested in the specs of the JL expander as I am sure Ehgemus could build a compatible host.

Yet another project looming I feel :)
 

Alaskan

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The beam is beautiful, divergence higher or not and for most laser enthusiasts that doesn't matter. In fact, a wider divergence adds a bit more safety for long shots unintended to land upon someone because of the beam weakening due to dispersion. But doesn't reduce the possibility of flash blindness to pilots because a wider beam is easier to hit them with, if someone were trying to do that, or on accident as happened to my poor cousin who went to jail over having done that :p
 

SteveT

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... or on accident as happened to my poor cousin who went to jail over having done that :p
Seriously, how long did he get? I must admit I am pretty weary about shining any of my lasers in the sky for too long as accidents can happen even when all seems clear.
 
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Alaskan

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They just booked him and released, it's the lawyer fees that were the worst, he is still on probation, years of it.
 
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That is AWESOME!! I love the host. Well done to Ehgemus. Really good looking focus wheel/adapter too. Elegant bit of kit with a fantastic output.

I really like 520nm, very nice colour to behold. Especially with a fat beam like that one has :bowdown:

I'd add rep right now, but apparently I need to spread it around before I can give you any more rep :na:

Thanks for posting the review, enjoyed it, well worth a look. Excellent work on putting it together, and very nice beamshots :thanks:
 

10fenny

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Damn I wanted that host!Great work!I feel those damn spendy direct diodes will be the death of me. I just blew my 520b. 85$ diode! and I want MORE!! The 520nm can be very bright with no IR which is awesome. Good luck with it. I'm pretty sure mine died from voltage input fluctuations! but without a proper autopsy IDK!
PEW PEW.
edit: I love the size comparison. I usually use mono bottle!
 
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Pman

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Welcome to the 1W+ club of beautiful 520nm;) Beautiful host to put it in too.
I'm wondering by your comment if you are saying that all of Ehgs side button hosts are momentary? Of course he can answer that himself;) +REP
 




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