Official specs: Osram Oslon Square, nr LCW CQAR.EC-MRMT-5O8Q-1 , 3500K, 80CRI min., angle 120 degrees, output 210-259 lumen at 700mA
The last of the batch of Oslon leds that I tested recently is the Oslon Square, I believe it to be the latest high power led in the Oslon series, although according to flaslightwiki it was first announced in november 2011. Of course for the best output I should test a cool white low CRI one, but being me I chose a 3500K 80 CRI (min.) led. I assume that apart from the lower output all other parameters should be comparable to a cool white one. The set-up (no picture this time, see my other led-tests for a look at my improvised set-up) consisted of the led reflowed onto a copper xpg-Sinkpad (it fits, but the solder pads do not completely match, resulting in that the led does not 'suck' into place like a xpg or xpe, you have to push it down or just use the right amount of solder paste), screwed (Actic Silver in between) on a block of aluminium, with a reflector placed on the board facing the white ceiling. The led was directly connected to a power supply, the current reading through the led was provided by the power supply, the voltage was measured by a DMM clamped to the led-wires. My lux-meter measured ceiling bounce lux-numbers, flashlights with known outputs were used to calibrate the numbers so the lux-numbers could be converted to estimated lumens. I tried to be as precise as possible, but my method/equipment is humble and limited so take the numbers as an indication of what is going on with this led, not as the absolute truth.
In the graph I compared this led to a XP-G2 measurement i did a few months ago. There is two things to consider when comparing the two leds, 1) the XP-G2 led had a AR-coated lens on top of the reflector, while the Oslon Square did not have one (for fairness add 1 or 2% to the XP-G2 values), 2) a 3500K 80CRI led will not perform like a 6500K 65CRI one, see below for a discussion of how to compare those.
Three observations from the graph:
1) the Vf of the Oslon square is very comparable to the XP-G2, so (at least up to 4A) it can be used as a direct replacement to the XP-G2, it can even be reflowed to a xpg-board although the solder pads (of all Oslon leds) do not match fully (see above).
2) the maximum output of the Oslon Square is reached at about 4,5A, which is respectable, but the XP-G2 can be driven harder.
3) up to 4A the Oslon square 3500K 80CRI measured an output that is 79% of the output of the XP-G2 R5 (I compensated 2% for the AR-lens). Now for a reasoning that I think is about correct: in Cree xp-bins 79% of R5 would be between Q5 and R2. If you look at the Cree version of this led, the XP-G2 3500K 80CRI led, it has a maximum bin of R2. So if the phosfors of Osram and Cree behave roughly similar in output when going from cool low CRI to warm high CRI, a general conclusion might be: the Oslon Square performs as good as the XP-G2, at least up to 4A. (this debatable line of thoughts would not have been necessary if I just had tested a cool white led, sorry about that ;-) )
I thought the led was nice enough to swap the xpg2 R5-3D that was in my Maratac copperAA, that I found too cool for a copper light ;-). For this flashlight I was already waiting for a while for the xpg2 3500K 80CRI to become available through one of the for me accessable dealers, but nothing happened sofar, I'm glad this one came along. Some pictures:
There it is in the Maratac pill. To my joy the board size for this pill is 10mm, so I could use one of the brand new VoB 10mm Sinkpads :-) . The solderpads for the led-wires on the 10mm sinkpad were too close to the led to clear the reflector, I had to solder the wires to the outer edge of the pads and scrape excess solder away. The reflector was electrically insulated from the wires with two layers of Kapton tape.
There you go, looking good in that light.
Not dead-centered, but the led was not dedomed and the OP-reflector is very forgiving: a good beam! And a picture of the front end of the light (on high) through an audio-cd, to see the die in action (led was centered worse in this picture, I improved that later).
White wall shots at 2.5 meter, fixed camera settings with white balance on daylight, left before, right after, the Oslon seems to give a just a bit tighter hotspot:
Performance results:
output on xpg2-3C: 330lumen, on Oslon Square 3500K 80CRI: 250 lumen
current draw was (as expected, the VF is virtually the same) 1,22A on both leds
throw on the xpg2-3C: 2.75klux at 1 meter, on Oslon Square 3500K 80CRI: 2.2 klux at 1 meter
This all compares well to the results from the graph.
Finally a few lights on high setting together, pictured through a audio-cd, to compare the die-sizes and shapes.
The leds from left-under to top-right: Oslon SSL80 4000K 95CRI, Nichia219 4500K 92CRI, XP-G2 cool white, Oslon Square 3500K 80 CRI
The Osram Oslon Square appeared to be a nice surprise to me! I tried to find these kind of test results on the internet, but apart from official spec's I did not find much, which is a shame really because in this case the led is on the market for two years and hardly ever considered for flashlight use (but there was a Surefire rumour..).
Thanks for reading!
