Emisar D4S review

Will XP-L HI and Nichia 219c be the only options?

I don’t have another idea to throw into the mix, but you mentioned only those two in your review.

Do you think that the extra size will be a better match, heat-wise for Nichia?

Might just have to carve out a replacement battery tube for it so I can make use of the iJoy 21700’s I have here…

I DO have a birthday coming up soon! :smiley:

This looks like it will be much more practical then the D4. What size are the aux leds and do you think it would be possible to reflow new ones of different colors? Also, is there any chance you could add the ability to turn off mode-memory on the firmware?

From the review: “on the low output mode, they’re close to the brightness of tritium vials”
I wouldn’t worry too much about cancer or affecting your sleep if you use the low setting.
Very handy for camping or if you’re sleeping someplace other than home and you don’t keep your light on a lanyard hanging from your wrist.
Also, current science says coffee is good for you, check back in a month, who knows?
If the Cyan isn’t a favorite maybe he’ll offer other colors or maybe have them match/coordinate with the anodizing colors?

It does seem very silly not to make the 26650 tube a few mm longer, so it could take a 21700 with a sleeve.

I’m not convinced the 21700 is going to become mainstream any time soon, but if making a 26650 torch today, it’s the obvious thing to do. Maybe it has already been done ?

But maybe Hank’s springs aren’t good enough to take up the slack. If so a small spacer or magnet would fix that. Such as the ones that Jaxman makes to interconnect flat-top 26650s.

This sort of thing: Page Not Found - Aliexpress.com

I still prefer 26650, for too many reasons to mention.

But a torch that could take 18650, 26650 or 21700 interchangeably would be perfect.

Hank, please take note before finalising the design.

Very, very nice work Thank you. I would add my voice to the suggestion to use other than cyan aux LEDs, and eventually to add a 21700 option. Meanwhile, when and how much?

I like red and warm leds for this better too but…

… as a guard of common sense: looking at popular articles without proper references only, this carcinogenic story is repeated everywhere, it has gained a huge following and that of course has its effect on phone companies who want to sell rather than follow the truth. But if you look for an actual scientific background there is some backup for blue light affecting melatonin levels (not a huge effect) but no proven relation whatsoever between blue(ish) light and cancer.

This kind of bogus blue light scare is why I’m not on here much anymore. Ridiculous.

Seriously doubt any ill effect from those wee cyan LED’s. Great idea.

What a great light. The auxiliary LED’s are a fantastic idea. I don’t have any 26650 cells, and I’d worry about the magnet near automatic watches, but other than that, everything about it makes it a must have.

Yes…that purple!

There have been some excellent lights recently released in the 26650 format - Thrunite, Lumintop, and now Emisar. I’m glad because I have lots of these cells, and it is a comfortable size for a hand grip. Too bad none of the big four battery cell companies are making these. 21700 may become the standard eventually, but probably still a few years off.

Sure I want one!
Hope Hank will sell the aux led pcb separately. I possibly buy 3-4 and make different led colors or multicolor boards to swap them as I want.

What are the benefit of using 21700 on the emisar d4s??

what a cool light, thanks for the review. can’t wait for it to show up in the store.

Yeah… the D4S’s blue light isn’t going to give anyone cancer.

Light, in general, tends to make people feel more awake. Particularly blue shades, but blue is also a component of white. The D4S’s 4000+ lumens of white light (of which probably 1000 is blue) are going to have a much bigger effect than half a lumen of glowy blue from the aux LEDs. Or on the low mode, it’s like 0.001 lumens. It’s completely negligible. The brightness is more important than the color. Even a 2700K incandescent bulb emits more blue light than these little aux LEDs.

Most people have at least some wakefulness response to light, but not all. Out of every 20,000 people, about 3 don’t have this response. Of those 3, statistically, 2 are actually blind. And I’m the other one. Because I see just fine, but my iPRGCs don’t work.

If you want a D4S to cause cancer, you’ll have to eat the battery or shine it at your skin point-blank on turbo, every month, repeatedly causing burns on the same place… and I’m not sure if even those would do the trick. But a tiny trickle of blue light is harmless.

The magnet is optional.

Well, the power you can push in the case of the D4S.

The highest current 21700 can push 35-40A. So, for people like Dale, you can put something like SST40s/Luxeon Vs/XPL2s and push even more power through for like 15 seconds.

Tesla designed the 21-70 to be optimal for their very specific requirements.

Which may or may not align with what’s optimal for torches or other consumer applications.

Too fat to be applicable to e.g. laptop cells or other stuff. Laptops in particular are going slim and light, with pouch cells.

As is every other EV manufacturer AFAIK. In the next two years the mainstream manufacturers will be launching real world affordable EVs, and no, they won’t be using a big pile of steel cased 71-20s, but big bespoke bagged cells, which pack far better. And can be thermally managed far better.

I sense some bandwagon jumping by those who blindly follow Tesla’s direction. They have built their Gigafactory(ies) based on a certain (bought in) manufacturing process which bought them fast time to market, and are pretty much committed down that path, but history will decide whether that is the best direction for the future. Or whether Tesla make it.

No other mainstream auto manufacturer seems to think so.

Watch this space.

What are you meaning about better thermal management?

It is always easier to cool off smaller cells rather than bigger cells, and battery packs using smaller cells are more reliable.