I have many EDC size lights, but looking to pick up a larger “search” light for my truck when out in the forest.
I want a good amount of throw with usable flood. I had originally decided on the SFT40 when Simon recommended the LHP531. I’ve been able to find some output and throw numbers for the SFT40 in the 3x21A and 3x21C (and confirmed those approximate numbers with Simon), but haven’t been able to find much on the LHP531. I’ve reviews calling it very floody, which isn’t what I’m after, but looking at the die size, it’s similar to an XML which is a decent thrower.
So the numbers I’ve found (or extrapolated from existing data and confirmed by Simon) for the SFT40 are:
3x21A: ~5500 lumens, ~265k candela
3x21C: ~12000 lumens, ~400k candela
Based off the datasheets, LHP531 would have ~50-60% increase in lumens over the SFT40 at same current. However, I haven’t been able to find any info on how much loss in throw/candela there will be. Considering the ~55% increase in total output, does that make up for some of the candela loss?
Anyone have an idea of what the throw/candela would be for the LHP531 in either the 3x21A or 3x21C?
Are you sure? 3x21A has 25A driver which means 8,3A per LED, SFT40 should make 2450lm each, we’re talking about ~7400lm. LHP531 - ~3850 per emitter, 11550 total.
Some? Yes. Is it going to outthrow the SFT40? Absolutely not, not even close, LHP is massive.
1lumen measured the SST40 version ~54xx lumens (OTF). I don’t know what bin of SFT40 Simon has, so I assumed a F9 bin, so not much higher than the SST40 version for OTF lumens.
That’s what I’m trying to understand, how much of a loss is there in throw considering the LHP531 produces ~55% more total output (lumens). I was hoping someone had some data or at least subjective info based on seeing the 2 LEDs in the same host.
i.e. Given the LHF is 3.3x larger LES than SFT40 and produces ~55% more lumens, candela is reduced by 30% (an example of what I’m trying to find out).
The LHP531 is 3.66x3.66 (LES). While a good bit larger than the SFT40 at 2x2m, it’s actually smaller than the XML.
I don’t want to get the LHP531 and be disappointed in throw, but I understand it’s a fairly new and not so common emitter so there isn’t much data out there.
Excellent analysis here, just wanted to let you know that the datasheet cites (3.72mm)^2=13.8mm^2 of LES for LHP531, so it’s a bit floodier than in your calculation, and 3.45x larger than SFT40. For reference, XHP70.3HI has 14.6mm^2.
Since 3x21C is already a floody light by configuration (7 emitters), I think it is sensible to get SFT40. The advantage is particularly apparent at low currents or sustainable drive levels: you need only less than 1/3 the power to attain the same throw.
It is quite surprising, as the 5050 footprint is generally not expected to support such a large LES! The LES actually extends way past the thermal pad. Datasheets suggest that the LHP531 may even outperform the 70.3HI at reasonable drive currents, despite having half the footprint. Crazy stuff.
If you don’t mind waiting, you could wait for the SFT42R to become available–Simon is testing a sample right now. It should both out-throw and out-flood an SFT40.
Oh, I don’t have a problem waiting. The only reason I was considering the LHP531 is because Simon said he’s releasing a 5000k version in a couple of weeks. I prefer neutral to warmer tints. If the SFT42R will have the same tint options as the SFT40 and outperform it in all aspects, I’ll gladly wait a little.
I have one 3x21C lhp531 6500k. It’s a beast of light, with about 900+m of throw and about 27k lumens.
It has a very good spill, so I consider a flood throw profile. I use the EVE 50pL and this battery is incredible for this light, not only for the output, but lasts forever…
I am quite excited for the LHP531 myself! The SFT42R does exist in 5000K, at least according to an unpublished datasheet. It could take a while, though, before it ends up in a light.
I’m looking forward to LHP531 4000K to swap into a Q8+, which is similar in beam profile to 3x21C, but has an OP reflector built for floody emitters.
It absolutely is. My concern for the OP is that the 900m of throw probably won’t last a minute due to thermal constraints, which is IMO not particularly helpful. SFT40 can triple the sustainable intensity. Of course, all this depends on how much throw exactly the OP needs.
Also, for a very floody light, one often needs more throw than specified because your eyes have to adjust to the high-brightness foreground, which makes them struggle to see dimly lit distant objects.
Yes, the 900+ m of throw is using the 54a FET turbo, and the light gets very hot really fast…
A technical assessment of both with graphs would be very helpful. @PiercingTheDarkness ?
Thanks Lumenizator Matheus for that data point!
I was targeting ~1km, so the LHP531 comes pretty close, but as QReciprocity42 mentioned, the foreground brightness impacts distant object rendering (especially with my not young eyes).
I’m very curious how the SFT42R will be. Looks ~18k lumens on Turbo and ~10k lumens on High. I understand Turbo likely wouldn’t last more than 1min, but I don’t expect to use that often. But it would be great to get 1km of throw even on High. Not quite the 27k lumens on LHP531, but I’ve noticed when I’m out in the forest, throw helps greatly to see what’s potentially coming toward basecamp.
I’m curious too about SFT42R, the datasheet specs look really good, but one needs to see some tests to be sure.
If you need 1km of ANSI throw, the LHP531 won’t do it at 900m, but comes close. If you need 1km of usable throw, then the LHP531 doesn’t come anywhere close–at longer distances one needs much more than 0.25lux specified by ANSI throw to make stuff out, as the reflected scattered light, i.e., the beam, blocks your view of the target. The SFT40 might have better sustainable throw than SFT42R, so if you don’t want to wait, it might be sensible to get SFT40 5000K.
I would like 1km usable throw. Sounds like 3x21C with SFT40 would meet that, and probably SFT42R also. I’m willing to wait to see how SFT42R looks, but it appears LHP531 may not be for me.
