TK's Emisar D4 review

I’ve only heard of one light doing the turbo-to-moon thing. I’m not sure if it’s a design issue or a fluke.

Please, measure the driver space.

More updates:

This is what the shelf looks like under the MCPCB. It’s covered in thermal goo:

The driver comes out with a bit of force from the inside, and it still works afterward when held in place only by pressure. Here’s what it looks like:


To get the driver out:

  • Unscrew and remove the bezel.
  • Pop the optics out. Hopefully it isn’t glued to the MCPCB, but if it is, this step could be tricky.
  • Unsolder the red and black wires.
  • Pull the MCPCB out.
  • Carefully push on the driver with a plastic rod like a spudger.

To get the driver back in, you may need to file down the edges of the driver a tiny bit. I did, because the glue around the edge made it slightly too wide.

The driver is 22.3 mm in diameter.

The shelf under the MCPCB is 4.5mm thick. :+1:

I think it may be giving me the finger, to protest being separated from its home.

Good news about the anodizing. I accidentally scraped part of my light with a bastard file while filing the edge of the driver, and after wiping the driver dust off I can’t even see where I scraped it. So the anodizing seems pretty tough.

Also, Narsil works on the D4 without any code changes. I flashed NarsilM.hex from the repository, and it just works. Moon appears to be significantly lower, too — about the same as my ZL SC52, or 0.1 lm. I haven’t actually measured it yet, but it looks pretty close.

However, runtime on moon isn’t dramatically longer. The driver seems to use about 4.5mA even without the LEDs on, so the absolute longest it could possibly run is about 28 days on a 3000 mAh cell.

I did a very low-tech runtime test to see what the curve looks like and make sure LVP works. To speed things up, I used an 18350 cell and did not recharge it first. I measured the output at 285 lm in my light box, then moved the light over to my runtime test setup. Note, the battery was not full; I had been using it since the previous evening and I think it was at about 3.9V or 4.0V. It didn’t really matter for this purpose. I also bumped the table a bit during the test, which made some small bumps in the graph.

What this shows is:

  • LVP works. It goes directly to moon in one step though, instead of doing a more progressive step-down.
  • Output on this mode, which was about 350mA on the 7135 chip and 350mA on the FET, has a gradual decline as expected.
  • I was too impatient to wait for the light to turn off completely, so I ended the test when I noticed it had stepped down to the lowest level.

My “test setup” was pretty ad-hoc. It looked like this:

Could you measure d and h of
the cavity in which the driver is located, please?

Thanks, TK for the detailed review !!

Fully agree !!
Figure, you’re using it during the day, meaning you need a fairly amount of light, but want to turn it off and on several times, you would always need to pay attention to release the switch at the desired level. :frowning:

Although I really prefer non-memory most of the time, I appreciate being able to optionally activate memory.

Of course, flashaholics probably will have (at least) one light with and another without memory. :wink:

Great review TK.
I must have a green one with 18350, it’s so cute.

Nice green. Shame it’s all glued. Looks nice though…

Cell ground goes to the driver trough battery tube end?

Does anyone know if this one will be available elsewhere? Shippingcost is making this less interesting for me.

Intl-outdoor will sell it was well (should be free shipping to NL), so don’t worry.

Thanks! Will wait for that. :+1:

Cheers! :beer:

In case you didn’t know, Hank Wang (member here as well) is the man behind Noctigon and Emisar, and Intl-outdoor is his business. The firmware for the D4 is most likely adapted now before he starts selling them on his site.

The output on this 18350 2 1/2” light is insane!

I know, right? I didn’t know one could get 2800 lm from an 18350 cell. At first I thought I did the measurement wrong.

… and I don’t even have those fancy new Aspire cells yet. I’ll have to get some, when they’re slightly easier to obtain. They make the shorty version of this light rather practical, even for pretty long nights.

On a related note, the springs are holding up unexpectedly well. Even after running at the maximum brightness with my highest-amp cell for thermal testing, the springs don’t appear to be sagging at all. Hank must have sourced some unusually good springs.

I’m surprised I haven’t damaged anything yet, testing this thing with thermal regulation disabled. It was so hot that I nearly burned myself just pressing the rubber button to turn it off.

I was under the impression that those springs are identical to that of the M43, see post #213: New 4XP Noctigon MCPCB for quad optic

The dark purple Efest 18350 will deliver the most current, the Aspire does ok and of course has longer run time, just doesn’t give maximum output.

Wondering what this little green meanie would be like with Nichia 319’s? :wink:

Next time I take it apart. It’s pretty shallow though; barely enough room for the tiny85 chip to fit. Something like this is way too big; even the capacitors may be too thick:

Yes. The only reason the driver needs any contact with the pill is for thermal measurement. The pill has no electrical contact.

I have the Aspire cells and switched to the Efest purples with the XPL Hi and crude burnt my stupid fingers in under a minute, just set it down and reached for something and turned around and picked up the light and that’s it burnt toasty fingers big time, the other two can run on turbo for a long time after you figure out how to keep it on Turbo, drops like a rock to moon in about 5 seconds but a single click will push it back to turbo and it will stay if you don’t ramp down even a 1/2 percent then try and go back up to turbo, it will just drop again.
Will need to tell R. about this and see if I can ship them back to be reflashed with Narsil like TK did…? Sort of annoying.

Edit: I tried to pull the spring and board out of the tail and it must be glued, but the springs are rock solid IMO, put in a protected and cranked on the tail cap and head as hard as possible to see if I could make a connection and couldn’t but the springs held up, put in a copper crush washer in the tail and a protected cell pany will work and not show threads. The tail end of the battery tube threading is not consistent, had they made the threading one more maybe two complete turns protected cells would work I think, but as they are now looking at the three tail caps they are all three at different angles with the branding, drives me nuts, anal something I guess, has to be dead on or it bugs me.

Aa you can see, slim one-side fet-based board contacts shelf from the one side and cell from the other. There is even no way to add extra 7135 over stock one.

Cheap and easy solution. Im not sure in pcb copper layer friction abilities, if they decided to exclude retaining ring, they could at least add thick (in comparation with 0.35mil cu layer) brass ring soldered to the driver.

That one light might be triggering LVP. The low-voltage behavior is to drop directly to the lowest level.

So it could just be a weak cell. Does the weird behavior move if you move the battery to a different D4?