SST20 vs XP-L HI

Let’s see if I understand this and maybe somebody can show me fact vs rumor on the comparisons between these emitters.

Assuming Cool White Tint and forget for now CRI (I know the tint snobs will say YUCK!)

SST20 has a slight CD advantage over the XP-L HI, yes or no?

SST20 uses more current than the XP-L HI (lumens: watt)?

XP-L HI generates less heat?

XP-L HI has a small lumen output advantage over the SST

Annnnddddd, Fire away members!

Bump, I would like to know this aswell.

1. The SST-20 is a throwier emitter than the XP-L HI.

2. The XP-L HI is more efficient than the SST-20 in general. That means:

- Same power than SST-20, more lumens.

  • Less power than SST-20, same lumens.

The difference in efficiency isn’t that large though. Either choice is good, but the XP-L HI has should be chose if price isn’t an issue in terms of brightness.

3. The SST-20 has a lower forward voltage than the XP-L HI. That means it can stay at a constant brightness for longer periods of time.

0. People who don’t care about tint and CRI are wrong.

  1. The SST-20 has more cd/lm such that a low-CRI SST-20 will have more intensity than any XP-L HI in most reasonable optics, and a high-CRI SST-20 will at least equal a high flux bin XP-L HI.
  2. Whether the SST-20 uses more current depends on the driver. Having lower forward voltage, it pulls more current with a FET driver (e.g. in my Astrolux SS with a VTC6, the XP-L HI was 4.0A and the SST-20 is 5.2A). With a regulated driver, there’s no change in current and output will be stable longer.
  3. Luminous efficacy (efficiency) is lower for the SST-20. That means a little more heat at the same current. With a FET driver where the SST-20 pulls more current, it’s substantially more heat.
  4. With a regulated driver, a high flux bin XP-L HI will have a little more output than any SST-20. With a FET driver, that’s uncertain and may depend on details like the number of emitters, total resistance of the circuit, and battery used. The high-CRI SST-20 in my SS is a little behind the original XP-L HI in output, but I suspect the low-CRI version would exceed it.

Certainly not Earth shattering info, but some recent tests I’ve run like up with what has been said thus far:

No one is suggesting buying a 70 CRI SST-20. Maybe for tint over an XP-L HD, but almost no one is buying 6500k who cares about tint.
The Cree has the raw lumen numbers and good marketing. The XP-L HI is a much nicer emitter to look at then the XP-L HD and certainly an SST-20 at low currents (green).

When we start talking about higher CRI and lower temps its not black and white.
I have some 80 CRI XP-L i love more than some of my SST-20, but generally the SST-20 is going to give you amazing colour rendition and the ones with good tint are more readily available than a Cree.

If you think the throw is great on the SST-20, wait until you cut the dome off it, its something else all together! More throw, less green.
Lets just say my carpet has a lot of SST-20 domes in it if you looked :stuck_out_tongue:

Hahaha, thanks for that, Jack!

I didn’t clock this thread was necroed and didn’t register the relevance of Jack’s post until i read gchart’s reply, would have replied to the OP if it wasn’t for you guys, thanks!

Eh, this forum doesn’t really have any rules against thread necromancy.

I don’t mind it either, it’s a good way to reference past information while adding new.

NO rules, great leds :smiley:

BTW, I vote XP-L HI :smiling_imp:

I agree, but I couldn’t pass up the chance at a bit of ribbing :smiley: :beer:

:+1: my post was for Marc E anyway :stuck_out_tongue:

Wow, i got something mixed up and thought this came from the new posts.
I opened a bunch of tabs and came back to it later and i thought i checked the date, must be been something else.

I need more sleep, dam kids.

Usually, when I bump an old thread, I start with:


and no one has complained so far.


(So while necrobumping is not against the rules, it helps if you point out that you know that you're doing it.)

What’s your de-dome method if you don’t mind sharing? Slice it close with a razor blade? Do you use any washer or spacer to keep from hitting the bond wires? or do you leave the phosphor “hump” over the wires intact? Thanks a ton, I wish all leds could be de-domed as easily as old Xm-L2s with heat and a scalpel to just pop it off

I was reading this thread hoping that Danthemanz was going to chime in with his technique. Someone who’s a pro want to give some tips before I screw it up?

I can’t find the thread super-easily, but tips have been given before. For SSTs and LH351Ds, the trick is an MCPCB without solder on it (besides attaching the LED of course) and a good reflow. Then, carefully selected washer thicknesses allowing you to shave the LED down. I’m not sure where the debate stands on multiple slices vs. one cut. Also, as a disclaimer, I haven’t done this myself - I’ve just been using TIRs with tint-shifty LEDs.

Thanks for the reply. I saw a couple youtube video where people de-domed the SST-40 and a XP-L Hi. The process was similar, shim up a razor blade and the. Cut across.

I am opting to not do it based on some specs I red on skylumen’s website where de-domed versions of flashlights were something like 2% more candela. Doesn’t seem worth the risk for me.

Wasn’t judging the resurrection of the thread, just the relevancy of me answering a 2 year old question as if it had just been asked :slight_smile:

As for slicing, i’m not an expert but i done a few with washers and a razor blade that has one side covered with insulation tape for (my) safety.
I’ve done both bare LEDs and LEDs mounted on boards that have clean, flat pads so the washers sit flat on the board. For a couple of LEDs i have a couple of washers with different heights so i take the bulk of the dome off in a first slice and then refine it with a slightly lower second slice, for other LEDs i only have one washer but it seems harder to get a clean slice this way.
The size of the hole in the centre of the washer is important, too large and there’s very little stability for getting a single, clean slice, if the LED moves with the razor and the slice stops it tends to leave a bit of a ridge. In fact that hardest part for me is being able to do one clean motion without encroaching on my fingers that are holding the washer.

I have done a couple of freehand slices as well where i’ve been too lazy to prepare the LED and board, the first one i did was a beautiful slice, the next two were messy… but got the job done i think, haven’t measured anything to know how effective they were.

Next time i will try heating up the dome somehow to soften it, will hopefully make the slicing smoother.