I’m hoping it’s a case of GT90 getting to market faster with the GT4 following on when it’s ready.
I’m just wondering if the price difference between the xhp70.2 and the sbt90.2 will be worth it. From my understanding the sbt90.2 is around $50 per led. Both LED’s produce around 5k lumens. Will the sbt90.2 be that much better than a dedomed xhp70.2?
You pay for throw, which, if expressed in candela of the hotspot, is directly proportional to the die surface area. The SBT90.2 has a die size of 9mm2 and produces no darker center in the beam and XHP70.2 has a die size of 16mm2 (1.8 times bigger so at the same output 1.8 times less candela in your spot) and has a slightly darker center in the hotspot. The XHP70.2 can probably be driven to a bit higher lumens than the SBT90.2 but it will never get its throw.
Also, XHP70.2 has a dome which pretty much halves surface luminosity by doubling apparent die size. And it’s a flip chip.
These are really a different league….
Forgot the effect of the dome, thanks for the addition Agro. So roughly three times the throw?
Yeah, very roughly 3 times throw intensity.
wont 4 sbt90.2 emitters make this a very expensive light vs the xhp70.2 ?’
they should offer both options imo.
Amen brother. 
Is there an official sign-up/interest list?
I’d be up for an XHP70.2 variant myself, but interested in whatever comes out.
Not yet since it has not even been confirmed that they are making it.
Given that the 90.2 takes some 20A plus to really make the difference, how are they going to pump more than 80A through the carriers?
Hey, it’s only 40A per carrier and 10A per 18650. It’s probably the spring loaded button on each carrier end that is the weak link.
If Lumintop is making the mcpcb they could also go 4S. So kinda like the 4S die of the 70.2, but instead of 9A they would need double, so about 18-20A.
It seems a bit extreme.
They would be run in series, so it would only need the 20-30A to power them all at 4S voltages.
I should have bought the damn prototype lol
Crazy, since M4D M4X announced it nearly 11 months ago and said it would be finished after the Chinese New Year. Ah, well, it happens.
bought ? lol isnt thats gonna be sent to vestureofblood ??
Jason, when two carriers are stacked the carrier in contact with the driver has to move the full current load. Even in series there would need to be 20A running through that contact carrier, one spring under the positive plunger with 240 watts flowing through it. I have yet to see a carrier that can handle it. I have seen carriers fry the traces trying. Which is why I asked…
If there is a pack?
2 carriers that each carry 4 18650 cells. The carriers are in parallel while the cells are in series. So technically the second carrier is all about run time.
I have no horse in this race, just trying to help out. IDK if they will even make a 4 x SBT-90.2. Anyway…
I think it was Kawiboy who modded his Lumintop SD75 with a FET driver and 70.2 and drew over 20A @ 6v. It basically uses the same carrier design as seen below.
Pic from Roadlesstraveled
I don’t know if 20A@6v will do the same type of current damage to the carrier as 20A@12v. Maybe? I’m a little fuzzy on this.
I know he had to add bypass wires, or maybe braided copper, to the spring loaded buttons to keep from melting the springs. After that the carrier worked fine.
IF, the carrier damage is the same for both voltages, maybe Lumintop can reinforce the carrier buttons and get good reliability.
Just a thought. This is what prototypes are about, test it, see what needs improvement, etc… :partying_face: