I’m starting to see more people put these LEDs (LHP531, LHP73B) in their flashlights and calling them “hand warmers” or “can light stuff on fire with ease”.
How bright do these LEDs even get and what are the specs?
Specs are available under the listings on the Convoy website.
No official tests yet (but some are on the way, courtesy of koef3), but the LHP73B claims 8500lm, while the LHP531 claims 4500lm; to me these numbers seem reasonable, and that a lot more output can be achieved by overcurrent–the output/current curve on the datasheet barely slows down. I would not be surprised if the LHP73B achieves a maximum well over 10,000lm.
The LHP531 has a LES approaching that of XHP70.3HI at ~14mm^2, while the LHP73B is even bigger at ~25mm^2.
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Is there a size difference between the two LEDs?
Also what’s the input current and voltage for each?
531 is a max. 9A 5050 LED, 73 is a max 16A 7070 LED.
3V for both.
Simon pairs the 531 with a 10A driver and the 73 with a 20A driver. I have a 73 with a 25A driver with no problems except the produced heat obviously.
All of them have very neutral light colours, the 531 6500K is my favourite light color of all LEDs at the moment.
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Where did you get the 20A and 25A drivers?
FYI: I got the LEDs.
Will test LHP73B 5000 K next week
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22mm 20A: 22mm 3V 20A buck driver for SFT-90 SBT90.2 LHP73B - Convoy flashlight
25A: 32mm 25A FET driver for L8 SBT90.2 ,input 3-4.2V - Convoy flashlight
I put the 25A driver that I made smaller in diameter in a Convoy L2 with a single-cell-mod.
the 22mm 20A driver is the “classic” maximum driver for the LHP73B, but this LED also works very fine with 8A or 10A drivers. 20A gives not a lot of more light, but a lot of more heat…
can’t wait for koef3’s test!
tested the LHP73B 5000 K
I am not impressed. 30 Amps max, at around 8900 lumens. Above 25 A the increase in light flux is very low, I would not exceed 20 A
More later in the test.
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Man i am REALLY excited.
But that doesn’t sound too bad. Nearly 100Lm/W at 30Amps ist better than the 78,3Lm/W (~8050 Lumens) a XHP70.3 achieves at 6,85V/15A according to your test.
For a LED that costs 1/4 of the XHP and delivers a much nicer tint that is not bad at all.
Just if you want to overcurrent this thing it might not be the best horse in the race, but again, the price…
I only buy a XHP70.x when I really need it, but I buy the LMP LEDs just because I want and because I want to have a certain stock of good LEDs on hand.
I just counted, I have 22 LHP531 and 15 LHP73B in stock, most on MCPCB in various sizes.
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In the current batch the tint is nice, but no one can say for sure this will be the same in the future. XHP70 can also have nice tints. Just some sort of gambling or getting good chromaticity bins. Especially the chinese manufacturers seems to like greenish tints, from my experience 
The price is the real advantage here. Considering the price it is a solid LED, but not in terms of sheer performance. More like a good allrounder. Since I am always want to see new milestones or developments (better efficacy, better performance, new materials/chips, new phosphor etc) in new LEDs I am not impressed, which does not mean that this particular LED is bad.
Edit: another advantage over the XHP70.3 HI is the higher luminance (15-20 % higher), since there is almost no sideways emitted light. This gives also a cleaner beam.
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Hoping that the tint will be consistently good, since that’s part of the selling point in the description.
From preliminary tests it does seem that this emitter does not offer any technological innovation–what it achieves it does through sheer brute force, by cramming as many chips onto the footprint as possible. But its good performance and extremely cheap price point makes it a very appealing option for flooders with good efficacy and tint.
There might be something to be learned from the spectrogram, once a test comes out–many people report incredibly good tints despite the low CRI, and it would be interesting to see how this is achieved.
For my sample I measured 0.0021 duv and 69 CRI.
The tint is ok, but definitely not rosy.
I can’t see anything unusual about the spectrum, it corresponds to that of many other neutral white LEDs. It has a big cyan gap.
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Du you also have the LHP531 for testing?
yes
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I just realized that the Changda SFN40 (warm white variant test here) is more or less identical to the LHP531; the LED chip size and footprint as well as the 3x3 arrangement are virtually identical. I thin 4800-5100 lm should be possible with the cool white LHP531.
I need to measure the SFN40 in cool white and an XHP50.3 HI also in cool white, both 70 CRI, as these are the real competitors to the LHP531.
By the way, I know why the LHP531 / LHP73B is probably so cheap. They use the same chip, just in different numbers/arrangements. Due to the extremely high order volume, they can probably push the price per emitter down significantly. I wouldn’t be surprised if LMP and Changda use the same identical LED chips from the same manufacturer.
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Changdas Emitters seem to be less efficient than LMP’s
In your test, the SFN40 has ~70lm/W at 10A while the LHP73B at 18A (10A / 9 chips * 16 chips) achieves 113lm/W
That difference is too big to be just because of the cct, I think.
Don’t forget that SFN40 in my test is 90 CRI, and warm white. The difference can be really huge.
Also the phosphor mixture alone can make a really huge difference in terms of efficacy.
Edit: Since the LHP73B is supposedly equipped with Sanan chips (I can’t verify this, I have to rely on Simon’s information in the shop), the same should apply to the LHP531. However, this should not change my statement about the extremely low costs, as the purchase quantities from LMP are likely to be enormous: per reel of LHP73B with 1000 LEDs, that’s “just” 16,000 chips, and they certainly produce much more than a few dozen reels per month…
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34 % to be exact. The SFN40 6500 K barely makes the 5000 lm, the 3000 K 90 CRI variant only got around 3300 lm.
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