Bad idea, or not?
I bought a 6*SST-20 board from led4power, the idea is to drop it in a C8 or M21A, powered by a Fet +1 and either a 30Q ot 40T Samsung battery. Now I remembered the SST-20s have a low forward voltage. Am I likely to pop a few SST-20?
Will kill the LED
you can’t run a single sst-20 in DD from those batteries without getting significant resistance within the circuit
is it the board with the fet on it?
The fet isn’t on the board, but there is a place for one. I’ve a few BLF A6 style drivers I was going to use, so didn’t need the fet on the board. There are 6 SST-20 in parallel. On SST-20 tests they seam to blow at 7amps. All things being even, I’m sure I wouldn’t get 42A at the LEDs, or would I?
I have a couple of unpopulated boards, which I was going to try with XPG3 and LH351B, but not finished (well not even started) my hotplate.
In the XPG3 and SST-20 data sheets, it looks like at 3v XPG3 draws ~1.6A and SST-20 draws ~1.4A. I’ve 4 XPG3 in a S41, which uses a fet+1, with no issue. So perhaps I’m worrying too much.
The FW3A uses 3 sst-20s with FET.
I’ve built several S2+ based triples with sst-20s and had no issue.
I don’t see why running 6 in parallel with a single cell could be a problem.
Thats a job for tomorrow then. Just need to decide if I’ll use the C8 or M21A.
He’s probably talking about the 6x 3030 board with 6x SST-20 for the Ledil ANNA optic.
https://led4power.com/product/6x-luminus-sst-20-4000k-95cri-led-sst-20-w40h-a120-on-34-0mm-6xv-anna-mosx-pcb/
It so happens i bought one too, since i already have the optic (and it’s on clearance sale now).
But this is 6 LED’s in parallel, so you’ll need a really powerful 18650 battery and optimized electrical path to push more than 20 Amperes.
Is the Vf of the SST-20 low enough to make that possible?
But here’s an idea for the topic starter:
Put a warm white LED in the middle to run on the single 7135 of the FET+1 driver.
Low modes will be warm white. :+1:
You could even stack an extra 7145 on top of the other one.
It’s perhaps a bit of a challenge to get an extra LED board in the middle and get the wires to the driver, though.
Oh, did you get the board with the FET on it?
(i should have read further than Lexel’s post…)
I have a triple SST-20 S2+ with a MTN FET+7135 and a 30Q battery. I haven’t blown the LEDs yet, but it sure will get hot fast in turbo. It has temperature step down, so I’m not worried about it getting too hot. A single SST-20 would not be good, same with a single Nichia 219 LED, but with a triple or more, they seem fine.
The 6xSST-20 was from LED4Power, without the fet. I do have another PCB for 7x3535, compatible with the 7x Ledil ANNA optic, with series, parallel or addressable options. I haven’t tried it, because it looked like a wiring nightmare, but could be an option for a dual temperature low/high set up. The XPG3s I have are 5000K and I know I have a 2700K XPG3 somewhere.
That didn’t go to plan. After assembly I checked everything was OK, but found a short. After dismantling I found the wires had shorted on the retaining nut for the spacer. During assembly I must have twisted the spacer and nut as I tightened the bezel, stripping the insulation on the wires against the nut.
Thats a job for another day. Its too cold in the garage for me to be grinding my nut down.
You’re using extremely fat wires there. Looks like AWG 14 or something.
AWG 18 or 20 should be enough.
But you should chamfer that hole where the leads go through the heat sink adapter to the LED board either way, so it won’t cut through the insulation.
It’s also a good idea to lead the red wire through the driver board and solder it to the tip of the spring.
You’ll have to drill a hole through the driver board, of course.
But you’ll bypass the spring and the tiny traces for the + to the LED that way, and iirc there is room for a hole near the middle somewhere, which makes it easier to feed that wire through that heat sink adapter thing too.
Where did you find that 7 LED board?
Is it DTP?
Cutter, and yes DTP and copper (TPAD).
I bought some others from RS as well, for Polymer Optics 282 7-Way (same spacing), but the LEDs are in series, so need a boost driver.