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Review of the new 15W LPM from LPS....

lasersbee

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I did a bit of testing on this LPM yesterday....
Here are some results...

It looks like a cute little LPM at first sight.

The first thing I did was look for a USB Charging
cable that was not included with the LPM.
It was drawing just over 500ma... I find that quite
high for the small Li-Po. I could be wrong.

First I need to mention that about a month ago I
re-calibrated our NewPort LPMs that we use for
calibrating our LaserBee LPM products as we do
every 6 months or so to kake sure they are still
accurate.

LiPo Charger

The LiPo charger used an off-the-shelf Li-Po Charger
Booster PCB to supply 5Vdc from a 3.7Vdc LiPo
battery. Unfortunately I damaged the Label indicating
the battery capacity when I unstuck it from the White
Silicone.
The PCB is held in place with Hot Snot as Dave Jones
would say.

I drilled a small hole just to the right of the USB
connector which now allows the light from the Charging
and Fully Charged LEDs to be seen while charging.
Unfortunately with the 2nd charge today the Charger
PCB gave up the ghost... I'l need to replace it.
Hope that is not a common problem.

Broadband Coating

I initially tested the LPM using a couple of close-by
Lasers and found that my specific LPM was reading
a little off.

808nm 500mW measured 556mW on 15W LPM... (+11.2%)
650nm 11mW measured 7mW on 15W LPM........ (-57%)
450nm 455mW measured 465mW on 15W LPM... (+2.1%)

By these quick non-in-depth measurements it looks
like the 15W LPM was calibrated at 450nm...
The problem is that the coating does not seem to
be Broadband as shown by the quick test above...

Max Power Test

We use a specific setup when we test our different
LaserBee Thermopile sensor coatings for Max Power.
We use a High Powered water cooled 808nm 40Watt
FAP Laser powered by an adjustable OPC-PS4005 Laser
Power supply.
I used the same Laser Beam Diameter and distance
from the 15W LPM Sensor and proceeded to increase
from 0mW upward.
The Sensor started to smoke at ~4 watts.... The
sensor is definitely not a 15 Watt sensor.

Sensor

Looking closely at the sensor I found it to be a TEC
that measures 10mm X 6mm X 1.5mm with ~50 P/N
junctions outputting ~159mV/W.
The 100% response time was ~21 seconds.

The actual Sensor Plate is a thin copper sheet that
is larger than the Tec and measures ~12.6mm X 11.6mm.
That plate is Paint Brush coated with some type of
black semi-shiny paint.

If a Laser is shone on the Plate over the TEC the readings
will be fine since the TEC will bleed off the heat produced.
If a Laser is shone on the Plate not over the TEC the
heat will build up quickly and reduce the Max power of
the sensor.

It seems that the copper plate is attached to the TEC
by the same white silicone that is liberally used inside the
enclosure. The TEC is mounted to the copper heatsink
again with white silicone.
The finned copper heatsink measures 26.9mm X 16.2mm
X 11.2mm and is also attached to the alluminium enclosure
by again... white silicone.
I can't see this small Heatsink capable of dissipating 15W
even if the Coating could handle it.

Circuitry

I decided to see what kind of circuit was used to
design the 15W LPM. Before receiving it..I was sure it
used the old simple $50 LPM circuit by MM that is freely
available on LPF.
It is however even more simple than that....
Schematic attached below...

There is no Manual or Digital Zeroing control on the circuit
but there is a voltage divider/Calibration pot that directly
feeds into an off-the-shelf Voltmeter that has the Decipal
Point disabled.

One thing to note.... If you touch the Alluminium case
the heat from your hand will lower the resdings..

Final Thoughts

If you want rough Laser Power measurements in a small
portable enclosure with a re-chargeable Li-Po battery then
this LPM is a fair choice. (Or you could build one since the
circuitry is so simple)


Jerry
 

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Lifetime17

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Jerry,
Great review now we all know the limitations down to the nub. Thank you for all the time you spent gathering all the info, Its priceless by far. Now Tommy can evaluate his manufacturing techniques and just maybe we will have a more dependable mini unit in the future.

Rich:)
 

GSS

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Thanks Jerry:) even with QC revision's on further builds of these, I see nothing but constant issue's:(
To good to be true:can:
 

lasersbee

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Thanks guys...
The main problem I see is the exaggerated Power
Claims... and the non broadband Coating.

I'm not sure if Tommy Builds these or is selling
them for someone.

@Lifetime17..
It might be helpful to the review of this 15W LPM
if you let the members know about a 405nm test
you did...;)

Jerry
 
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Lifetime17

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Jerry,
Very well Ok i did a test at 18 inches from the thermopile surface coating . I used a BDR 209/405nm Output at 900 + mW's and the coating still smoked and burned, This is a big issue .
The coating will determine the life of the LPM integrity to the consumers and all of us at LPF . So between Jerry accumulating all the info of his testing and mine combined well all in a nutshell save your money till this unit is revamped . Sorry to say expectations were high here at LPF maybe next time around.

Rich:)
 

lasersbee

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Crap... smoking at 900mW....:eek:
I'm waiting to see what Tommy has to add...:thinking:

There is no way this LPM design was ever
tested properly before selling it... IMO..

Jerry
 
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Lifetime17

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Jerry,
Look at it this way we saved the members here some cash as we were the sacrificial lambs so between us about 160.00 shot in the you know what. Hey you know something it was a fun ride and the best is yet come in responses .

Rich:)
 

GSS

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57% off from a 650nm just doesn't cut it..and sensor smoking at 900mw's??
Have you guy's tested a lower powered 532nm yet? Still trying to make an excuse for this meter:whistle:
 

Lifetime17

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Hi GSS,
i will do a test on the 532's i have from you. they might be ok with this mini. Like i said this LPM might be only good for the double digit outputs.

Rich:)
 

astralist

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And here I thought you'll do these Jerry :D :whistle:

I'll test it alongside my Astalist LPM for wavelength
bandwidth and Max Powers and accuracy.

BTW, it would be great to provide your standard LPM specs and (more importantly) the sensor type as well
Even with my recently calibrated Ophir sensor, because of the difference in original calibrating wavelength, they give a different reading to one wavelength.
 

GSS

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Jerry,
Look at it this way we saved the members here some cash as we were the sacrificial lambs so between us about 160.00 shot in the you know what. Hey you know something it was a fun ride and the best is yet come in responses .

Rich:)
And yes this post went over my head when I first read it..
$80 each out of your own pocket for a "review also" on a product that didn't seem to cut it with more than a few issue's right from the start doesn't sound right:(
Yes Jerry, i'm wondering now if it was ever tested, or was it;)
Tommy has to make good and i'm sorry for saying it but the LPF isn't here to review products for ebay or is it:(
 
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Lifetime17

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Hi GSS ,
You are correct about paying for an item to review and have it flunk testing in so many areas. Well we gave it a shot and were bitten. I doubt if Tommy will make good but if he does all is well.
So far we didn't see a response pertaining to all the tests so only time will tell for now and waiting to see what he has to add.

Hey a sales thread might be in order." Title Free Mini LPM that doesn't work as stated"

Rich:)
 

Encap

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And yes this post went over my head when I first read it..
$80 each out of your own pocket for a "review also" on a product that didn't seem to cut it with more than a few issue's right from the start doesn't sound right:(
Yes Jerry, i'm wondering now if it was ever tested, or was it;)
Tommy has to make good and i'm sorry for saying it but the LPF isn't here to review products for ebay or is it:(
Exactly, I have to agree with GSS.

LPF is not part of the private vendors internet web site business nor a part of the garage sale mentality for the most part site, ebay.
Tommy has received a lot more from LPF members on other products he offeres than he has compensated them for already for whatever reasons but this LPM situation is just playing members for fools whether knowingly or unknowingly, the real world situation is the same.

Tommy should refund the price paid to both Lasersbee, Lifetime, and SOSDD--what's fair is fair--the unit as delivered are not as described unusable junk.
The unit was put up for sale on his web site as a finished product, announced and offered for sale in the LPF BST sub-forum, and purchased in good faith but the product is not even close to what it should/is supposed to be.
The business situation is the same regardless if done knowingly or unknowingly--serious misrepresentation, garbage level construction, inaccurate, and faulty in several ways, not functionally as described--in short defective from the get go has been clearly shown.

Whomever designed and built the unit clearly had little, if any idea, of what they were doing or why and if they did it is an even worse situation where they knew and didn't care.
 
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BowtieGuy

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You guys are all correct, LPS/Tommy should make good on on these obviously defective LPM's, and he hopefully will.
These should never have been for sale in the BST, but maybe offered for testing at no charge, then there would be no harm done, if the LPM sucks, it gets a poor review and nobody buys one.

I guess the old saying holds true in this case ...."If the deal is too good to be true, it probably is"!
 




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