Luminus SBT-90 gen2 5700K tested (SBT-90-WDS-F72-SA600 SA-H4, from Neal)

Thanks, I am builiding a quad SBT90.2 light and wanted to know the limits. I am using 8cells so VTC6s maybe would be too much?

2 cells per emitter. Maybe better MJ1 or 35E…

No - I wouldn't use MJ1's or 35E's. All depends though on the resistance. If you have added resistance in thinner LED wires, carriers, springs, then you won't achieve 20 amps, but maybe that's what you want? MJ1/35E's will just further lower the amps, like using 24 AWG instead of 20 or 18 AWG LED wires.

Yes - over 20 amps. Hit 22A or 23A on a couple single cell lights. Probably could hit higher - think Dale or KB went higher than 23A.

I've seen a bump in the roughly 19A to 22A range, but hard to tell for sure, but figure about 5% bump.

I'd guess peak is about 24-25 amps, might be hard to achieve but possible with multiple 30Ts, 18+ AWG wires, etc.

I thought I saw that the GT94 was running at 30 amps?

Total? 4 LED's?

To really drive 4 of the 90.2’s will take around 80Amps total. The problem is cell capability and capacity, if capable then capacity is usually an issue.

In my scratch build DBC-07 I use 4 Sony VTC5 5D and a single 90.2 still only does 5390 lumens, even from the 124mm reflector. I don’t have amp draw on this one.

I have a SS/Cu X6 that will pull 23.1A for 5100 lumens, the 35mm reflector is probably the bottleneck there.

Most output I’m seeing is in my K1 that Tom inspired me to modify, with a 30T and 16ga leads it can make 6130 lumens at a draw of 18.2A.

My new Lumintop X9L does 4700 lumens on a 40T.

By comparison, my DBC-06 with a 96mm reflector around the CFT-90 draws 18.1A on a Trustfire 32650 and 22.8A on a 30T… 4240 lumens and 4610 lumens respectively.

Difficult to feed the hungry Luminus powerhouses…

Most of these are not new cells, all readings are at start, on fully charged cells, taken moments ago.

Not sure. Check this post out. Just before the sentence in bold.Official Group Buy Now Live! Lumintop BLF GT94 4x SBT90.2 20,000 lumen 2400m Throw monster! - #2 by Texas_Ace

Figure if the fV is up around 4.2 (or higher) to make 400 watts it will have to pull 95Amps. If it CAN do that it won’t do it long!

Ohh - this must be a 2S2P LED configuration, so it's 30 amps, but at double the voltage of a single LED. I forgot that the GT94 is wired up like that.

I can’t figure it Tom. These really pull up towards 4.5V when pushed to 25A. That is why a single cell can’t deliver what they need. Or am I thinking about the CFT-90?

Ah, yeah, my bad… spec sheet calls for a 3.4V at 22.5A so indeed I was stuck on the CFT.

Sorry for the confusion.

Looks like a single 30T then maybe max's at about 23 amps, but with multi-cell setups like in the GT90, could go higher I'd suspect. I've been modding GT carriers to 4P and getting good results in a converted GT->GT90. I should figure out a way to measure amps in one of these.

Weren’t there K75 measurements somewhere that showed turbo at like 28A?

edit

28A might be beyond the peak, maybe not. Dunno what kind of driver that is in the K75, or if the measured #'s were stock or not. Guess multiple batts helps a lot.

Did VOB measure the GT90 amps?

I think the cells are in series in the k75 and its a serious buck driver. Because of the effort it would take to design that driver, I’d be shocked if acebeam overdid the current.

The Vf was only 3.5v at that current level though, so there must be some series resistance we are missing in multi 21700 configurations. Parallel 30Ts are going to hold wayy more than 3.5V at 28A (14ea). Even a single 30T should overwhelm this emitter in a 0 ohm circuit.

But then again, it only takes 15mOhm @20A to drop 0.3V

That thread is sketchy - missing pics, missing details, so not sure what he's really measuring, or how for that matter.

djozz could not get that high in amps to test the SBT90.2, but even at 20 amps, it was starting to flatten out - I'd guess roughly 25 amps would be flat in his test. So maybe there's a little more life at 28A when the LED is cold, dunno. I got a few pretty serious low resistance SBT90.2 builds and I'm peaking at 23 amps on a 30T at best, so maybe doubling up 18 AWG wires, and maybe improving over a SIRA20DP FET, dunno, but seems like ther'es not much there for single cells.

I’m going crazy these days not being able to fit the light hobby into my budget. The only thing I bought in the last 6m months was a skilhunt e3a. But if I get a chance to buy the 4x18a 90.2 version this year that’ll be my Christmas gift to myself. I have a 5V 100A power supply I can test this led with. If anyone has an emitter they would send me I can set up perform a test, but with this emitter I doubt that’ll happen. I don’t yet have a calibrated lumen sphere/tube, but can easily get relative numbers.

Contact resistance, bypassing traces, and parallel FETs are the heavy hitters (i know you know this). I wonder how much can be gained by increasing contact area with the cells and higher pressure. What is RTSon for that FET? 20cm of 18awg is about 4mOhm. So 2mOhm is about all you could save there in practicality.

Wondering bout parallel FET's - thought that was a bust? I thought maybe TA tried it and got no advantage? I even thought it could do worse, maybe a timing issue? This is very fuzzy with me, can't recall where/when/who. The HK90 has places for 3 in parallel, populated 2, but I replaced the 2 with one SIRA20DP. Think they had older Infinions in there.

Don't assume too much with me - yeah, some things I know, but not everything for sure

Issues with parallel FETs can arise at low duty cycle and high frequency AFAIK. But at WOT in turbo, parallel FETs can only reduce resistance. But with the FET you are using has an RDSon of about 0.8 milliohms. This is 5x less than your wires.

So between the wires and FET you have about 5mohm. That accounts for about a third of what I’m spitballing to be your total. Don’t know how much the traces on the driver, mcpcb, and tailboard are contributing. Bypassed blue springs are about as low as you’ll practically get. That about it. Short of bypassing the driver and getting a comparative lumen value idk what to suggest that isn’t radical.