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Review: Shenzhen Keyuan 405nm 500mW (668mW pk)

astralist

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Mar 27, 2011
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This is my first review, and this is my first laser that i buy directly from a manufacturer company.
as im not a native english, so i won't talk much here :shhh:

Manufacturer: Shenzhen Keyuan CO.,LTD.
Model: Handheld Laser H405L-500
Wavelength: 405nm
Power: 500mW


Spec on their website:

-nothing-

Actual spec:
Wavelength: 405nm CW
Power output: 668 peak (using 3.7v 16340 batt) and stable ~230 (using 3.0v 16340 batt)
Transverse mode: TEM00
Beam divergence: Not measured yet
Power Supply: 2x16340 3.7v or 2x16340 3.0v
Current draw from batt: Not measured yet
Dimension: Diameter:23mm, length: 170mm, weight: 165g.
Focusable: YES
Price: $100 + 20 shipping via DHL


Section 1: Dimension

It comes with a nice case.



Nice host.


The aperture shutter


The heatsink

When the laser is turned on for several minutes
the only parts of this laser that become hot is this heatsink.
IDK if they using a brass instead of aluminium on heatsink.







Tailcap is using a contact terminal, not using a spring. this is good because it won't scratch your battery.


Driver is well covered by plastic and the hole within the spring is also covered by sponge.
sometimes it isn't important by other people, but it's important to me.



The focusable mechanism.





Section 2: Measurement

LPM used: LaserBee 2.5 Watt USB
Link: LaserBee 2.5 Watt USB


Ooops.. before turn on the laser, lets take a look at this :D




First measurement is using a "FAKE" Sony LR123A 1800mAh 3.7v Li-ion battery

why i said that it is a fake? because when i buy these, it wasn't on its original packaging.
its only wrapped by a common accesories plastic.
you can see in this measurement:


Fresh "fake" Sony battery

you can see that its drop fast on 30s. so after that, i recharge it again, and then running a measurement once again

Fresh "fake" Sony battery

It reach 668mW! but drops again on 30s. then i think that this is because of duty cycle.
so i turned it off about one minute, then turned it on once again


Used battery from previous measurement

Oh yeah.. the power was drops again at 30s..

my first thought was this is caused by duty cycle of this laser, then i remember that i'm using a FAKE SONY BATTERY..
so it was caused by a fake sony battery
:crackup::crackup:

Second measurement, this using RCR123 Tenergy 3.0v 900mAh Li-ion battery.

This battery has a voltage of about 3.7, but the regulator kicked it down to 3.0-3.2v while running.

Fresh Tenergy battery

A lower powered but stable output power! :wave:
It is stable at about ~230mW for more than 5 minutes! :wave:

you can see, my problem was on battery. :crackup:



Section 3: Beam profile

Just wait for update ;)


Section 4: My subjectives

Pros:
  • Nice host with complete safety features, feels sturdy, and its small enough to fit in your pocket.
  • Very smooth focusable mechanism, easy to twist
  • Very good quality for a low price, among all other company. :bowdown:
  • Overspec and a perfect round beam.
  • Straight beam (the beam doesn't come out from the aperture with an angle)
  • Good customer services.
Cons:
  • The aperture shutter is a bit loosy.
  • We need to have them built about one week after we pay for it.
Other thought:
Shenzhen keyuan or known as S-KY laser or Skylaser has a poor advertisement on their websites, i even don't know that they sells this until they send me a quote for their handhelds.
AFAIK, www.skylasers.com is their US ripeoff site. but now, they turned it off.
and AFAIK, www.texaslasersystems.com and www.rayfoss.com are their resellers.


I will update this thread soon :thanks:
 
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blakegriffin

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Re: Shenzhen Keyuan 405nm 500mW

Great review.:gj: It would be cool to see some beam shots or a burning vid I bet that laser burns like a beast.
 

astralist

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Messages
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Re: Shenzhen Keyuan 405nm 500mW (668mW pk) Review

yeah.. i'll update this soon ;)

altough this is a high power, but it can't burn fast if not focussed. because of its big beam (about 5mm) :(
 

Eudaimonium

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Say what, near 700mW output peak but 230mW stable power?

There is something VERY wrong here. This is 405nm direct diode laser. It shouldn't even *have* peak and average/stable power. Output is supposed to be constant and that's that.

Here's my best guess - The lithium pile batteries that are 3.0 V are actually the ones you should be using, but they are very weak and discharge in 30 seconds, resulting in full, although even too high power of 700mW (more on that later).

Batteries you are using which are lithium ion ones, with 3.7 V voltage (actually 4.2 V fully charged) are actually giving off too much voltage and regulator has to dissipate it as heat (which is what linear drivers do), and driver is overheating and in turn, reducing it's current output so it does not fry itself (which is, again, what linears do).

There are several lasers out there which use 2x CR123 batteries and excplicitly mention NOT to use 3.7 V lithium ions.

This brings several conclusions: First, they are using a simple linear step down current regulator (alikes of which are we using as first learner's drivers), which is incredibly cheap, inefficient and unreliable - much like your laser! The type of regulator they should be using is a switching driver, preferably boost (step up) driver to use with one 18650 battery), if not then buck (step down) to use with two CR123 but much more efficiently.

Next, output power of near 700mW is way too much for any 405nm violet laser diode. Best diodes you can get are pulled from 12X bluray burner drives and are proven to degrade and die really fast if you feed them more than 425 mA of current, that is have an output power more than 500mW or close to it (which would match the laser's description).

My own opinion - I'd return the laser for refund.

For $100 you can have an expertly made 12x 500mW bluray laser by people here on this forum that will be better than this in all aspects, save maybe for the host aesthetics.
 
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Fenzir

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^hmm. I was thinking there was something wrong with the output because my PHR build stays at a constant 103-108mw for minutes, and that's it's peak.
 

X FLY

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Aug 18, 2009
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Say what, near 700mW output peak but 230mW stable power?

There is something VERY wrong here. This is 405nm direct diode laser. It shouldn't even *have* peak and average/stable power. Output is supposed to be constant and that's that.

Here's my best guess - The lithium pile batteries that are 3.0 V are actually the ones you should be using, but they are very weak and discharge in 30 seconds, resulting in full, although even too high power of 700mW (more on that later).

Batteries you are using which are lithium ion ones, with 3.7 V voltage (actually 4.2 V fully charged) are actually giving off too much voltage and regulator has to dissipate it as heat (which is what linear drivers do), and driver is overheating and in turn, reducing it's current output so it does not fry itself (which is, again, what linears do).

There are several lasers out there which use 2x CR123 batteries and excplicitly mention NOT to use 3.7 V lithium ions.

This brings several conclusions: First, they are using a simple linear step down current regulator (alikes of which are we using as first learner's drivers), which is incredibly cheap, inefficient and unreliable - much like your laser! The type of regulator they should be using is a switching driver, preferably boost (step up) driver to use with one 18650 battery), if not then buck (step down) to use with two CR123 but much more efficiently.

Next, output power of near 700mW is way too much for any 405nm violet laser diode. Best diodes you can get are pulled from 12X bluray burner drives and are proven to degrade and die really fast if you feed them more than 425 mA of current, that is have an output power more than 500mW or close to it (which would match the laser's description).

My own opinion - I'd return the laser for refund.

For $100 you can have an expertly made 12x 500mW bluray laser by people here on this forum that will be better than this in all aspects, save maybe for the host aesthetics.
Sorry if I didn't understand that message properly, but from what I know the Li-ion batteries (Blue Tenergy 3.0V) have an built in regulator that drops them to 3.0V (so it's not the lasers driver that regulates it). The cheap batteries, although crap, give the laser a lot more voltage (3.7V) which results in more power. We need a pair of good quality 3.7V batteries to confirm this.

EDIT: http://www.batteryjunction.com/rc390reliba.html "Despite the voltage regulation at it takes the voltage regulation ~12 milliseconds to activate."
 
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Eudaimonium

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No, that is wrong.

3.0 V batteries are simply made with such internal chemistry that they give 3.0 V.
Well if you want to get technical, they are 3.6-3.7 V fully charged and will discharge until 2.2 V.

ALSO - I see that I've made the mistake in my post. It's Lithium ions (4.2V full) that give you short 700mW peak - after which they are depleted, and Lithiums (3.0 Avg, 3.7V full) only give you 200mW.

In this case I need to reconstruct my opinion :p

However I am STILL going with driver overheating. Those that give you only 30 seconds power, try using the again after say, 2 minutes to let the laser cool down.

Do they still perform the same as before, even if you didn't recharge them?

EDIT - That voltage regulation seems to be refering to the protection circuit of the battery which shuts it off during overcharge and short circuit. I think :undecided:
 
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