Single LED 21700

Hey guys.
Rather new here, came across this forum thanks to Adventure Sport on Youtube and thanks to the rabbit hole that I’m gleefully tumbling down, I’ve gotten an itch to construct my own light(s).
Already have picked up a few Sofirn SP31v2 and C8Fs, the latter I’ve become very unhappy with, likely because of the fat head that it has, but am happy with the body tube size, which lead me to the Convoy S21A Host kit and that can handle 20mm Drivers and MCPCBs no problem…

Which leads me to my predicament: I’d like a single LED which can max out to 1800 to 2000 Lumens and a Driver board that can push it.
Been debating between the Cree XHP35.Hi, the XHP50.2 (3V,6V, and 12V) and the SST40. Cannot seem to decide between them, and like to have a clean white light throughout the powerband.
Also thinking about at one point LED4Power’s LD-4 series drivers, MTNElectronics seems to be out of everything…

If I have to construct and flow my own boards, not a problem, I have access to all the SMT equipment thanks to where I work, even Loneoceans GXP172 Driver doesn’t make me blink but I don’t think that would be advisable for a first build right now…

Before I ramble on any further, asking for some help at this impasse :slight_smile:

I’d worry about beam profile before setting an arbitrary number for how much total ouput you need. Those emitters all have VERY different beams and tints.

LED4Power’s drivers have a very limited range of current, not a variety of low, medium, turbo, etc. modes.

If I were building the light Id use a 4000K LH351D and a FET driver from MTN Electronics like the MTN-20DDm. Still easily past 1000lm, great tint, balanced beam and manageable heat with a driver that has tons of options (with Bistro or guppy3drv for the firmware).

XHP35 are great but both that and drivers for them are expensive and options are limited. Some of the boost drivers available right now have been tested to be kind of lacking lately too.

Yeah. I guess I’m looking for something with a decent mix of throw and flood, since I usually use my lights fairly close and focused, sometimes have to light a good sized area at maybe a dozen or so yards away.
Haven’t really given much thought about optics TBH at this point.
Also yeap, I’m leaning away from boost drivers for the same reasons: lack of testing, availability and sometimes cost.

That’s one of the innate problems with picking A Light, that it’d likely be a compromise. I don’t believe there’s any such thing as “good balance between flood and throw”, because cranking it up to get good throw in the hotspot will make the foreground right in front of you annoyingly bright and wash out what you’re throwing at. Unless you’ve got a deep reflector like the HS-801, which pushes out the spill way out in front.

Close-in, you will want a flooder, else it’ll be like lighting up things with a laser-pointer. But throw will absolutely suck even at 2k lemons.

Farther-out, you’ll want a throwier light, but then close-in, laser-pointer again.

I have issues choosing between my MH20 and MH20GT for precisely this difference, yet they’re almost identical other than the beam profile.

So, I often carry more’n 1 light, ’20 in my pocket, others in my bag. Right tool for the job…

Might be worth looking at the JKK21700 (Kaidomain, AliExpress, Banggood, etc) or Astrolux EC01 (Banggood).

Oh, and welcome aboard!

Edit: I read too fast… just noticed that you want to construct your own light. That’s awesome, and kinda invalidates my recommendations. My apologies! Carry on…

heat is always the enemy

I went with the XHP50.2 3 volt. At 4.56 amps (12-7138 chips) I get 1790 lumen with no fear of cooking the LED. This driver was built for the host you picked. At 6 amps probable just over your target brightness at 2300 lumens with a J4 bin. Not exceeding Cree’s current recommended max. which happens to be 6 amps.

Oh yes! That’s why I’m thinking of a 21700 host. Got more meat and surface area to dissipate heat.

Thanks! I looked at that awhile ago, spec wise, almost exactly the same as my Sofirn SP31v2 but with a bigger battery, and a bigger head on it.

Well I’ll be…
I was just eyeballing that exact driver earlier, but for the SST40, not the XHP50.2-3V. There’s an idea.
Hell… I won’t be going turbo often enough to truly worry about it, certainly good for the occasional giggle :wink:

Ya make good points there. I’ll be looking more into flooder type reflectors and all that.

My second pocket-light is a Xeno E03 in WW. A little floodier, but some diffusion film on the front glass would make it a hella nice flooder. How diffusey the film would determine the ultimate beam profile.

Some DFs are plain, and you’d have to open up the light and sandwich it between glass and reflector, while others have adhesive and can be stuck on (and peeled off, even repeatedly), so you can swap different types of DF, or none at all.

The question will be if you want a specific CCT/CRI.

At 3V, any of the larger die emitters (SST-40, XHP 50.2 3V) are going to have limited CCT options, namely +5000K and poor CRI. The largest selection of emitters and drivers will be a 3V, smaller die (XP size, or 3535), paired with an appropriate driver.

At 6V your options are much better, but you’ll need to find a boost driver. H1-A is a cheap, readily available option, the two drawbacks are limited modes (simple 4-mode) and recently it looks like they’ve downgraded some of the components for it to be less efficient.

12V (XHP-35 HI) is really more of a pain than it’s worth IMO.

Pre-made SST-40 S21-A’s are available at the Convoy store, just plug in a battery and go

Not in my experience, the drivers can have up to 5 modes + moonlight (with a choice of 3 moonlight levels), max can be switched between constant current and direct drive, max constant current mode is adjustable and the modes will alter as percentage of the max current chosen, and you can choose between 4 drivers which deliver max current between 2-3A, 4-8A, 7-9A and 8-12A.
Sooo, what did you mean by a very limited range of current?

In response to your clean, white light requirement, i’ve not seen one in action myself but the Luxeon V is meant to have minimal tint shift across the beam, the XHP50.2 will be a bit multi-coloured as it transitions from hot-spot to spill. The SST-40’s not too bad though.

I guess I should have clarified a little better :slight_smile:
Meant from Low Power to Medium to High to Turbo Mode power levels. So long as I get a decent sized, wide hot spot, or none at all if a dedicated flooder, I’ll be happy with it.
My steadfast requirement is that this thing needs to be pocketable without it being overly huge.

Was very tempted with the Convoy SST40 prebuilt light, but the review on it said that it heats up so fast that as soon as ya flip on turbo, it starts stepping down.
So right now, thinking about the LED4Power 6A board with the remote FET and XHP50.2-3V.

Convoy L21a with XHP35 hi

Coolness :slight_smile: The output would put me on the lower end of my target, but this would be more ideal.
But the problem is the driver, aside from the GXB172, what would you suggest for this particular LED?

I don’t know what you mean, it’s stock 12V 2,3A which is the sweet spot for XHP35

See TA’s test here

Here’s a link to the light

Wellp, that’s normally what you get when the light’s small enough to be pocketable. Not much thermal mass to soak up heat before everything else gets hot, few if any cooling fins to help dissipate heat, etc.

Yeeeeeap. Nature of the Beast.
But the SST40 is known to not be the most thermally friendly if memory serves.


And don’t be tooooo disappointed if your first 20 or 30 don’t give you “exactly”,
what you wanting .

There’s LOTSA blokes on here been looking and experimenting for yrs.
And still looking. Chuckle.

Enjoy the life mate. it’s very diverse. and often frustrating.