TK's Emisar D4 review

I also tried sticking my blue-colored D4 Ti bezel on my D4v2 Ti’s copper head. it fit fine.

Note however, that some of the titanium pieces… the bezel and the tailcap… will not fit on the aluminum head and body tube. But that is not unique to the D4v2. The original D4 and its Titanium version had the same problem.

i tried this one. does not fit. the threads are slightly different. all Ti’s. was gomna swap the heads since the v2 is only available in raw color.

This video shows that the SS bezel and D4V2 magnet cover is suitable for D4V1 https://www.youtube.com/watch?v=3bG-JNVL0Nw

Not all V1s fit ss bezel. Only for those from later batches. For example, my black D4V1, which I bought at the end of the V1 sale, has a different thread than the white D4. Ss bezel matches black, but not white. It’s a lottery. If you bought D4V1 late then it will rather match. For some reason, after putting ss bezel on the white, the gap is much larger.


I received a secondhand D4 today, how does one go about updating the firmware on this light?

Also, is it recommended?

You can if you want to, but it doesnt really matter unless it was avery early D4 with the first gen thermal management. Personally if it hasnt been done already id just switch it to Anduril and call it a day.

Check out the first post of this thread. You need to pop out the driver in order to flash the Attiny with a SOIC8 clip.

I’m not looking to take anything apart, but what does switching it to Anduril mean?

Changing the Firmware from one user interface to another. The D4 originally came with a firmware called RampingOS, later batches of the D4 came with an updated RampingOS or optionally Anduril.

If you dont want to take the light apart, you cant update or change anything.

What are the differences in the ramping OS’s, how would I know which I have?

Also, what changes does the Anduril have?

i have the original Emisar D4 that Hank kindly flashed Anduril before shipping it to me in June of 2019. not sure which version. i think the OS is technically for the D4S?

anyway, i want to increase the thermal regulation cutoff. i think it steps down too fast on turbo. but even with watching YouTube videos, i still don’t get it.

anybody have straight forward instructions? i think i have to use my infrared handheld thermometer? i don’t think it’s the OS where you just hold the light and click a button when you think it’s too hot to hold. i’m american, so i only understand Fahrenheit :wink:

i love this light!

If it is Anduril, the code installed on yours is more likely for the D4v2 not the D4S. In any case, just follow the Anduril instructions in the post immediately before yours.

I believe the late production D4 has the D4v2 driver board with pads for flashing. So you basically have a D4v2 engine but without the fancy bits (secondary leds, knurled battery tube, etc.).

I’m guessing the new K1, D4v2 Ti blue swirl and D4Sv2 will have the above version?

They should just do 15+ clicks and it will blink out the firmware date in YYYY MM DD format blinks.

Good tip, is there somewhere that gives date brackets with firmware versions?

i figured it out. i have an infrared thermometer. calibrated the temp to 25C… i did 40 clicks above 30C… so 158 degrees. a little nutty, but i’d turn the thing off way before that. it still steps down… but sucks the battery dry a lot faster. is 40 clicks possible or is there a limit to the thermal cutoff?

70C is the limit. You can click more than that, but that will set it to the max of 70C anyway. If you want to fake it out to get the max set to 85C for example, calibrate room temp to 7C or so. That should help even more. 22C is ~72F (22 * 1.8 + 32).

thanks Tom! yeah, i was wondering about cheating the room temp calibration… but other than experimenting with the”limits”, i realize it’s kinda pointless to make the thing melt in your hand. LOL!

it still dims even in my hand… given it’s RIDICULOUSLY hot when it does it… i assume the light hits an internal temp of 158 degrees on turbo fairly quickly anyway?

Well, probably, but I'm not sure I trust that internal MCU temp sensor much. Can't do much with 4 LED's maxed out in such a small mass with such a small surface - not much of a thermal path, or, the thermal path is so good getting to the outside, that's why it heats up so quick. Gotta take a light like this for what it is - super power in a small package for short uses, or any lower power level you'd like for practical longer term use. For example, a few mins ago I used my EDC18 on a low setting to trouble-shoot my gas furnace. The mag tail meant I could place it perfectly above the area I was working in, and at 100-200 lumens or so, it can run comfortable at room temp.

Better heat sinking of the driver would help - most of these kind of lights don't take the driver heat sinking seriously. More metal to metal contact between the driver and shell would help, as well as potting the driver. Now that we got external pin re-programming capability, potting should be considered.