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

Yes, the cell contributes a whole lot, but here I’m starting with the voltage under load of a 30T based on HKJs data and reported Vf values from djozz and other’s. It’s seems safe to me to estimate a 300mV drop is occurring at 20A elsewhere in the circuit. The FET doesn’t seem like a meaningful contributor according to the spec sheet.

Djozz and MRsDNF conducted switch resistance tests years ago and found between 1 and 10 mOhm values across different models and current levels. switchtesting , (june13th2015:additional test by MRsDNF in post#44)

If you can, check output of mechanical switch lights with your bypass and compare with tailcap installed. These could show a large difference at times. Those that do though don’t usually last that long.

Ok - looks like I didn't recall the tests I did correctly.

SBT90.2 mods from notes:

Brinyte B158: 25 amps on a 25S

UF 1504: 24.5 amps on a GOLISI 26650

Just measured:

K1: 24 amps on a T50

K1: 23.6 amps on a 40T @4.21V

The new Vapcell T50 5000 mAh 21700 is for real, at or close to a 40T.

T50 sounds great. VTC6 of the 21700 world.

And those amp draws look more in line with what I’d expect. 5-10 milliohm is typical for a good FET light.

I really think it might be a Samsung 50T, which I don’t know if it actually exists, but we historically were slow to learn of these new cells. One thing I’m hoping for is the ‘s’ line of Samsung 18650s (or even an ‘r’) to make it to the 30 series. I think by now there is room to improve power density and maintain 3Ah

Hhmm, 50T sure bout fits it's performance.

But how fast does the T50 drop off compared to a 40T

I'm not really set up for doing long term testing. I did get in another pair though of the T50's

I don’t understand how to read the chart. For example, to achieve 4000 Lumens the lamp will consume 59.4W of power, right

I know this ^ was a while ago, but I want to put one in a light that came with an xhp50, what did or do you use for “centering ring”, or more specifically so the reflector doesn’t short out in the mcpcb? I have been thinking about cutting a thin piece of plastic just so the reflector has something to sit on, would that work?

In what light? I had a few lights that had the Gen1’s 90/70’s in them that I salvaged from older lights/builds… In the FT03 I didn’t use a centering ring… I used Kapton Tape to cover the mcpcb from shorts…I was using the MTG2 26mm boards until Hank came out with the 32mm….

His tests were not done in a lamp/flashlight. They were done in a sphere measuring the raw led with a power supply.

In a battery powered flashlight with it’s added losses (let’s use a conservative 20% loss) you would need 5000 total lumen to get 4000 out the front of the lamp. That would be about 18 amps. Then you need to consider the voltage sag. A decent 21700 might sag to about 3.8 or so. 3.8 x 18 = 68.4. So I would estimate about 70 watt is what a flashlight would consume.

If your talking about a raw led powered from a power supply, you can see that 4000 lumen draws 12 amps at 3.15 volt. Thats only about 38 watts. These not very practical numbers for real world use.

Personally I’d estimate a 30% loss and say you need to push it to 20 amps and you might be lucky to get 4000 lumen out of a flashlight.

These are all my own estimates based on djozz’s test results, as I haven’t ever used or measured this led. Maybe someone who has tested it in a flashlight can give some more detail.

Information is wonderful. Thank you my friend.

Awesome thank you. The 32mm baord fits in the ft03? I was going to order that from hank but thought ft03 had a 28mm mcpcb/

No…You will have to run the 26 mm MTG2 board in the FT03… unless you bore the shelf out wider…

Has anyone been able to test this on a power supply that goes over 20A?

I have a 30A supply. Just don’t have a 90.2

I find over AE stores very cheap SBT90 LEDs like this
https://www.aliexpress.com/item/32845013580.html?spm=a2g0o.search0304.0.0.12b0754fWiOqy0&algo_pvid=220fc2f8-8ba4-496e-a9c8-289d828d22da&algo_exp_id=220fc2f8-8ba4-496e-a9c8-289d828d22da-1
Are they genuine or fake?

They look genuine, and I have seen that store before, so it is not an extremely obscure source. But do not blame me if they are fake after all.

Listing just says SBT-90, not SBT-90.2. Even the datasheet specs included are for the old SBT-90, looks like to me. I sure wouldn't trust a listing like that if it's a SBT-90.2 you are looking for. Can't imagine anyone interested in the old gen of this LED.

What does the 2nd generation sell for, $20 or $40?
That ad shows $17 which seems more like the older led.
Price alone seems to point to it being the older unit.

Yes, I missed that it may not be the .2 version, in that case you get a way less performing led not capable of 20A.