The There Are No Stupid Questions Thread

hey thanks Jason!! got it.

Is it possible to use SST20, LH351D and Nichia 219C together in a direct drive setup for tint mixing? Would they differ much in brightness or burn due to different forward voltages?

The LH351D and SST-20 would not be a problem in this setup, since the high CRI variants have very similar VFs.

The 219C would cause problem however. don’t know how much.

Yes, that is what I supposed. I wanted to try the SST20 and 219C 5000K together to increase rosiness and get a 4500K tint. They would get around 3 - 5A per led. Do you think the 219C would draw more current than is good for it?

So I might need to mix LH351D and SST20, throwy in the center and floody outside, not bad either.

You really need a wider CCT variance than 1000K to lower duv significantly. Most 5000K, 90+ CRI 219C bins are pretty green anyhow.

Why don’t some of the more expensive brands have lvp built in

Expensive does not mean better.

That aside, you might need to be more specific.

It just seem sensible feature to me extra safety but I understand you shouldn’t just rely on it. I was just thinking why they wouldn’t include it, i would not use one without lvp when using Li-ion Batteries even protected ones.

All the expensive lights I know of use it. What is an example that you know does not have LVP?

Recently tested a new zoomie by Wuben.

While it has both the throw, and the clarity, the convex lens doesn’t seem to have
The photon density of a comparable reflector.

Would appreciate knowing why a reflector casts a much more robust circle of light. :beer:

Most “zoomie” designs waste a lot of light when the LED is highly focused because there is no reflector or TIR optic to capture what is shone to the sides.

Both of the latter capture almost all of the light an emitter produces. I would say “photon density” sounds like intensity/candela though, and zoomies can actually still blow away reflector or TIR lights of the same bezel/head size.

Like BurningPlayd0h said, it’s about optical efficiency. Typical zoomie efficiency between wide angle and narrow angle can be a factor of 3. It might put out 900 lumen in wide mode, but only 300 lumen in narrow mode. It has terrible efficiency but it can still be pretty intense and throw a long distance.

Did we answer your question, because I’m not sure what you were asking about.

Thanks for your responses.

To my eyes, when focused on a distant object, the convex lens throws well, and the
Object can be seen clearly, but it seems like a flat projection while a reflector’s
Light seem more robust, and illuminates with what seems like a more intense beam.

Is it possible a deep reflector throws most of the photons into the projected beam, while the
Zoomie is less efficient in doing so. With losses. In arcs of artifacts :question:

Not unless the lens or focus is completely f*’ed

Reflectors tend to put about 50% of OTF light into the hot spot. The other 50% goes into the spill.

Zoomies put maybe 30% of the light into the narrow focused beam. Something like that. If it’s focused exactly, they basically project an image of the led die. There is no coma or corona around the edge like with a reflector hot spot.

Maybe the perfectly straight columns of light from the projector/convex lens gives that flat appearance. The reflectors columns of light are not perfectly straight. It tends to blend the beams of light together more for a smoother hot spot. IDK, just guessing.

Something to haha “reflect” on.
Guess the robust hot spot is spot on for me. :smiling_imp:

Again, thanks for your responses! :beer:

Adding a protection on batteries is not free ! It costs some money, some space and even adds to self discharge and internal resistance so it make sense to add it only when it is really required.

I don't know who you mean exactly with "more expensive brands" but imho the big names like Sony, Sanyo, LG or Samsung don't include it because most of the batteries they sell are used in packs (think electric vehicles, power tools, laptop PC, ...) witch use a battery management system that already take care of lvp and several other things.

The market for batteries with individual protection is a very small one compared to what they are used to deal with and they seem to prefer letting smaller companies taking care of that (and buying their unprotected batteries ;) )

That’s not what he is talking about.

He is only talking about LVP in lights, not cells.

None of the “Big 5” li-ion manufacturers produce any cells with protection circuits or button tops at all AFAIK.

But as for expensive lights without LVP, I can’t think of any except maybe Surefire, etc. that are made to run on only CR123s?

I would have a question. If my understanding of the Li Ion cells manufacturing is correct, there is only handful of original OEM manufacturers like Samsung, LG, etc. Most cells on the market are rewrapped OEMs from these companies. Could someone fill me in on who are the manufacturers behind various Chinese brands of 18650 and 21700 cells then? Brands like Golisi, Liitokala, Lishen, Shockli and so. Do they run their own OEM factories beside the well known big manufacturers?