Head2Head! LCK26K/NichiaCS/MJLED/LCK65K/LoV35K

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This thread contains testing data on various LEDs. It included lumen maintenance, spot output of various types of LEDs, a plot of forward voltage (Vf) versus forward current (If) as well as some beamshots.

One of the main thrusts of this post is to display the effects of overdriving 5mm LEDs. Some LEDs do not have very good lumen maintenance (how well a LED retains its brightness over time) when overdriven or even when driven at their rated current.

This first post will be updated with summarized testing data.
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"BEAM SHOTS - LCK26K vs NichiaCS"
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The Nichia (NSPW500CS - Color B Intensity U) LEDs were purchased from Grumpy's group buy. I had a chance to compare them to Smitty244's 26K LED (ebay 26K) group buy. The beamshot comparison setup was three CR2016 button cells in series with the two LEDs connected in series to ensure they got the same current. The output level was quite similar (perhaps a slight edge to the Nichias in center spot brightness) but I preferred the color of the 26Ks. The 26Ks seemed a more uniform white color and the Nichias had a blue center with a yellow ring.

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Pre Burn-in comparisons
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The first set of pictures are some pre burn-in comparisons against some known lights.


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Before and After Burn-in
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This next one is a side-by-side comparison of the LCK and Nichia LEDs before and after burn-in for 147hrs at 57mA. Note that at 57mA the LCK was run at almost 3x rated current compared to 2x for the Nichia. The reason I selected this current is that it is close to ArcAAA current.




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LUMEN MAINTENANCE: </font><font color="red">LCK 26K</font><font color="blue"> at 30/41 mA
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Because I pushed the LCK 26K LED so hard in the previous test, I ran another couple of tests on a fresh LEDs to determine what a "safe" operating current would be. The LCK 26Ks look fairly stable at 30mA. Some of the variances/measuring error could be due to ambient light in the room, searching for the "hot spot", and changes in ambient temperature. Output drop is 8.8% after 48hrs continuous running. Good drive level for a flashlight but not great for a lantern or nightlight. It appears that 2x rated drive current is a little too much for the LCKs as well. There's a 35.5% drop in output after 48hrs at 41mA.



Here is the advertized spec of LCK 26K LED


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LUMEN MAINTENANCE: </font><font color="red">MJLED</font><font color="blue"> at 75/105mA
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An uncut MJLED was tested at 105 and 75 mA. The results started out looking very promising but went downhill fast at 105mA. The data looks good for 75mA - there has been no noticeable degradation. Here's the graph:




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LUMEN MAINTENANCE: </font><font color="red">LCK 10mm 65K</font><font color="blue"> at 20/30/40mA
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Here are the results of the 20, 30 and 40 mA burn-ins of the LCK 10mm 65Kmcd LEDs provided by rdshores. These LEDs have a published If spec of 30mA, so I started them with a "relatively safe" overdrive of 40mA. After seeing the results I did another run at 30mA. After seeing those results, I tried 20mA.

The top curves are Lux at 1m and the bottom curves (which all start out at 100) can be read as percent of starting brightness.



Here is the advertized specs for the LCK 10mm LEDs



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LUMEN MAINTENANCE: </font><font color="red">Ebay LoV 5mm 35K</font><font color="blue"> at xx mA
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Hookoo sent me some of these Light of Victory (LoV) 5mm 20mA 35Kmcd LEDs for testing. I have started at 30mA (because if it's good at 30 there's no need to go to 20mA /ubbthreads/images/graemlins/smile.gif). These are starting out much better than the 10mm ones at 30mA. The epoxy lens on these LEDs are not tapered like the Nichias.



Beamshot: Left - LoV 35K, Right - Nichia CS


Here are the Published Specs of the LoV 35K LEDs



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Spot Output Comparisons - various currents
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This is an output test (Lux at 1 meter) of various LEDs. (the legend is stacked according to the plot lines - top to bottom). I ran the three LEDs from about 12 to 70 mA and continued up to 105 mA for the MJLED.

These numbers are for spot intensity at 1 meter and do not represent total output. The beam width is narrower for the LCK and Nichia LEDs (and much narrower for the 10mm LED) so they give higher spot readings, however, my impression was that the MJLED gave more overall output at the same current. I base this observation on being able to read labels much better from the bounced light off the ceiling. I may have to make one of those light boxes.



This has been presented before, but here is my version.

Here is an interesting chart on LED efficiency vs current. The chart reads as percentage of rated current output vs percentage of rated current. Confused yet? The 100% mark is at the "rated" current for each LED. I placed a linear diagonal line to show what a linear relationship would look like. Brightness is not directly proportional to the current.

For example:

When the Nichia LED is run at 12mA (40% of rated current) its 48% as bright as when run at rated current. In other words, when the current dropped 60%, brightness only dropped 52%.

Also, when the Nichia current was double the rated current(200%) the brightness only 163% of the rated current brightness.




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Voltage vs Current (Vf vs If) - Various LEDs
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Here are the Voltage vs Current plots. This illustrates how careful you must be when driving the MJLEDs with a voltage source (just look at the driving voltage and project the current - imagine what current a Li-ion would produce).



Thanks for looking,

Paul

Re: Head to Head! 26K vs Nichia

I saw some insinuation that the 26k's get dim rather quickly. I'd be interested in seeing an actual metered test, measuring the output before and after running the leds for 1 week at 50 mA.

Re: Head to Head! 26K vs Nichia

paulr, I hadn't heard of that. Looks like we need a burn-in test. /ubbthreads/images/graemlins/mad.gif (I'm not mad - I just liked the burning (burn-in?) graemlin /ubbthreads/images/graemlins/wink.gif). I will try to set one up this week - 50mA sounds good. BTW, the ArcAAA w/ the 26K (the third photo down) has had a couple of run-time tests on it (perhaps a dozen hours or so).

Paul

Re: Head to Head! 26K vs Nichia

Thanks for the pics, chimo! I'm debating these two sources as well for a few mods. I like the color of the 26ks, but I would go with the nichias for durability if that ends up being a major issue. /ubbthreads/images/graemlins/cool.gif

Re: Head to Head! 26K vs Nichia

Can you be more specific about the insinuations (current levels, observed time to deteriorate visibly)?

According to tests, good quality white 5 mm LEDs should deteriorate to 50% brightness in about 2000 hours at 50 mA and 300 hours at 100 mA. Was it faster than that?

Re: Head to Head! 26K vs Nichia

As a side note, I've had 2 (out of five) 26Ks go permanently into strobing output after driving at 6V. (2 fresh 2016). /ubbthreads/images/graemlins/frown.gif

They obviously don't like 6 volts! (or more accurately, the current from the new 2016s).

Re: Head to Head! 26K vs Nichia

My experience with the 26k is they are very intolerant of high current - I had a Dorcy AAA with the 26k, a Lion aaa killed it fast, while the stock dorcy aaa LED lived to tell the tale.....

Re: Head to Head! 26K vs Nichia

As far As I Know, The GB's Nichia are NOT the ones which Photon Freedom MAX is using. Similar.. but not Same!

If you have Freedom MAX, Please have that beam shot added too. That will be real comparison.

The GB Nichia's are just an Upgraded version of Old Nichia (Notice the Beam Patern is similar, but brighter)

The New Nichia's (photon Freedom MAX) are U/V Grade, i.e. RGB Phosper over UV Die

Re: Head to Head! 26K vs Nichia

[ QUOTE ]
ViReN said:

As far As I Know, The GB's Nichia are NOT the ones which Photon Freedom MAX is using. Similar.. but not Same!

If you have Freedom MAX, Please have that beam shot added too. That will be real comparison.

The GB Nichia's are just an Upgraded version of Old Nichia (Notice the Beam Patern is similar, but brighter)

The New Nichia's (photon Freedom MAX) are U/V Grade, i.e. RGB Phosper over UV Die

[/ QUOTE ]

Viren, I don't see any reference to Photon in my post above. None was made and none was inferred. Why isn't this a real comparison? I am comparing two different LEDs from a couple of recent group buys. I even threw in some other well known lights for additional reference. People had expressed interest in how they compared against each other. I don't have a Freedom Max to compare it to (or I would). I wouldn't mind seeing that comparison as well.

Paul

Re: Head to Head! 26K vs Nichia

no the GB on nichia are the same of the Freedom/Proton like the guy of LRI just say in this forum: U rank

for me the nichia U rank is the best 5mm available, not only for the spot that isn't so better than other but for the total output and for the beam pattern.

nichia's leds are also designed for run continuosly at 30ma without any accelerated degradation and at 100ma without blow.

the wide range of operating temperature (-30 +85 C) allow to overdrive it without problems

Re: Head to Head! 26K vs Nichia

Chimo, First, I am sorry if I have offended you in any way. I didnt mean to do that at all.

There is still some confusion.... (atleast to me) ... after looking at your Beam Shots.... the AAA Arc (having Nichia) & the NextGen Nicha (that you have tested) dont have 2 times the output.... this let me think that FreedomMAX has different kind of Nichia LED, (especially after seeing Reviewer's Beamshots) on a web site... they didnt have that "pink" Corona kinda thing... rather there was a Slightest of Yellow....

David, Are you sure ? do you have both... the LED's, I would love to see such a comparison.

The reason that I would like to see such a comparison (between GB Nichia's) & the Freedom MAX Nichia's is because ... I too want to Upgrade my Photon Freedom's (which are dimmer than Photon III that i have) with the New Nex Gen Nichia (that freedom MAX) is using. If they are same, I am considering buying the from the GB /ubbthreads/images/graemlins/wink.gif

It's True, Nichia's are great... no doubt there at all... and most importantly I like Nichia LED's too...

For Me, I wont even consider 26K at all (even after looking at your pictures)...

My Personal Experiance has been that Old Nichia's (Photon Freedom ones) can very well survive up to 100 ma for atleast 2 minutes (tested in my 19 LED Nichia Cluster Lamp) ... and Others (all of which i have tested) didnt even go up to 70 mA .. they were DIM soon!

Chimo (Paul) ... Please do not take me wrong pal... i am once again sorry for any of the un-intended offence. Please forgive me... I hope we are cool...

Re: Head to Head! 26K vs Nichia

Viren, no problem. I plan on doing an accelerated "burn in" on each. It'll be another month or so until I get a light meter so I can't test the actual intensities. I will pick a couple of sacrificial LEDs from each batch and run them through some current ranges (say ~50mA, ~75mA, ~100mA) to see if intensity drop is detectable by the eye. I will post the results. Cheers,

Paul

Re: Head to Head! 26K vs Nichia

I haven't much experience with 5mm LED's. I do know I have been running a 26K i got from kevinL in a solitaire easymod with 12V's. and have had none die on me.

And looking at my oldest modded soli, the LED is still
about the same as it was brightness wise when compared to a new one, and my other LED's including a photon X2 LED I got to put in my freedom. To my eye, the 26K, nichia 2X (don't know the real name) and what ever i got in the peak ultra power 1xAAA are all real close, with the 26K soli with 12V and the nichia being a bit brighter, esp the nichia.

BTW, who makes the 26K, anyone know? I also here there is gonna be a 30K soon. Also ANY idea what LED peak uses in the snow ultra power? VDG

PS, a kind CPF brethren sent me an email to learn to post
pic's so maybe i will try to do so! peace

Re: Head to Head! 26K vs Nichia

Thanks Paul. /ubbthreads/images/graemlins/smile.gif

VDG:
Peak as far as i know have Cree LED's .. they are good ones too... (price/output) ratio is best for Cree

Nichia 2X are the NSPW500-CS Variant ... often said to be U/V Grade LED's

The U Rank LED's Have Max of 22000 MCD @ 20 mA (min is 15500)
The V Rank LED's Have Max of 31000 MCD @ 20 mA (min is 22000)

There are 2 Ranks in B Color Tint .... One is B1 & Other is B2

The Peak Materhorn High Power & Photon Freedom's Beamshot is here....
.. Yes they are Very White... as compared with Nichia's (especially when compared with Photon Freedom being overdriving the LED's @ 40 - 60 mA that too by 6 Volts... notice the Angry Blue)

Re: Head to Head! 26K vs Nichia

Thanks bro! The peak look's like mine, but I imagine that's the "standard" freedom not the X2? I do love my peak materhorn lug 1xAAA ultra power! small bright and for a 1xAAA it produces real throw, something I have not seen in a 5mm led, except for the soli mods w/26K LED i do with a modified reflector and 12V's so i am digging about all of these LED's.

I wonder how the photon 2X would look against the
26K, and the jupiter i got coming.

Really with all these option's on 5mm LED's, it's a shame that more light maker's don't offer them as option's.
Well I am gonna try some beam shot's and see if i can learn to post them! VDG

Re: Head to Head! 26K vs Nichia

For those looking for the Nichia group buy info regarding model number, bin, etc... here is the link.

I could not find the real spec sheet on the 26K ones. They were purchased by Smitty244 on ebay. (Search for LCK World Trade Center on eBay 26000 LED it had a partial data sheet but did not have manufacturer info.)

Paul

Re: Head to Head! 26K vs Nichia

vdg: Yep ... Its a Standard Photon Freedom. and this is why i was also looking to upgrade to the New Nichia LED.... Chimo's post has been very helpful in explaining the 26K & the GB Nichias.... but I still have this confusion ... because from the Beamshots... the CS Nichia is looking just a tad bit more bright... /ubbthreads/images/graemlins/frown.gif

we really need some shots with Freedom MAX ... and with the Grumpy's GB Side by Side

This will really help me decide on wether to go for the GB LED or not...

Re: Head to Head! 26K vs Nichia

viren i haven't a photon but here what chanik of LRI say "It's over 300Cd now with the 6 U grade Nichias on a NiMH."


this mean:

1) they use U grade nichias

2) U grade nichias output 50cd at 65ma /ubbthreads/images/graemlins/mad.gif

Re: Head to Head! 26K vs Nichia

The burn-in has started.


As you can see, the LEDs are running at 57mA.
The measured Vf's (@ If=57mA) are as follows:

Starting Vf's
Nichia: 3.66V
26K: 3.45V
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@12hrs in
Nichia: 3.66V
26K: 3.43V</font>
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@22hrs in
Nichia: 3.65V
26K: 3.42V </font>
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@26hrs in
Nichia: 3.65V
26K: 3.41V </font>
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@29hrs in
Nichia: 3.65V
26K: 3.41V </font>
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@39hrs in
Nichia: 3.65V
26K: 3.41V </font>

Paul

Re: Head to Head! 26K vs Nichia

[ QUOTE ]
nerdgineer said:
Can you be more specific about the insinuations (current levels, observed time to deteriorate visibly)?

According to tests, good quality white 5 mm LEDs should deteriorate to 50% brightness in about 2000 hours at 50 mA and 300 hours at 100 mA. Was it faster than that?

[/ QUOTE ]

Nerdgineer, thanks for posting these numbers. The rest of this post is just food for thought of the readers of this thread. /ubbthreads/images/graemlins/smile.gif

People often put down the 5W Luxeon for the 500hr figure especially compared to the 100,000 hour figure that keeps popping up for LEDs.

Lets do some math for the 100 mA, 300 hour figure of the 5mm LEDs.

First of all, an assumption. Let's assume that someone uses a light with one of the 5mm LEDs driven at 100mA for 10 minutes a day, every day. (My average may be one to two minutes per day).

300 hours x 60 minutes/hour = 18,000 minutes.
18,000 minutes / 10 minutes/day = 1800 days (to 50%)
1800 days / 365.25 days/year = 4.928 years

Now the 300hrs may also be a little on the harsh side as the LED is not being used on continuous duty.

That's almost 5 years! Assuming you are like most people who frequent this site, you may purchase lights at a more frequent rate than that. /ubbthreads/images/graemlins/wink.gif If the light output is not acceptable by that time it's a good excuse to buy a new light! ("Honey, my LED's getting dim, I need a new light....") /ubbthreads/images/graemlins/wink.gif.