[short review and modding] Emisar D4

LED Flashlights – General Info 18650 Flashlights
1

I received today a Emisar D4 to change its XPG2 S4-5D LEDs with Nichia sw405 D240 CRI92 and spring bypass it

So I can take a look inside it

finished light

Size comparism

Spring bypass


I also noticed there is very little solder paste on the springs but they seem to hold fine

Threads are cut square very nicely

The light is build like a Tank shelf and all walls are very thick even the tube

The driver is so designed that the MCU and AMC have contact with the shelf, so temperature reading of the MCU should be pretty precise, I do the same on my Klarus XT11GT Repairs with Narsil driver

It uses a Infineon Power-MOSFET, BSC009NE2LS5 in PG-TDSON-8 (also know as Power SO8 or LFPAK56)
This FET looks pretty good from datasheet comparable with beating the Vishay ones in low Resistance 1.2mOhms @3,5V

I wish the side switch would have LEDs like my Q8


The LEDs are reflowed with very much paste, it would be better to give em a tap to push solder out to get it as thin as possible or use less
the LEDs are reflowed with Leaded solder

Reflowed Nichia SW405 D2450 CRI9050 in it

Used my temperature regulated heat plate

Gave the LEDs a tap to remove too much solder, so also a lot solder blobs are all over the place
carefully aligned the LEDs to the markings if they were off
Used a little weight to push the LEDs down while cooling the heat plate with water filled pot

Light is now drawing 15.8A at 4.1V Sony VTC6 battery
Compare to the BLF Q8 with one battery with same charge level and type as in the D4

I also looked at intl outdoor website again and noticed the XPL Hi are now +18$

Conclusion:

Overall well build light and UI.
Great optics and MCPCB.
Pretty short for a 18650 light, possible EDC in pockets.
The only downside in my opinion is that the switch is not lighted.

2

I was told that bypassing the spring is meaningless in D4. DBCustom even replaced the FET (and gained lumens this way), but didn’t do a bypass. I guess you don’t have a direct comparison, do you?

3

These are Be-Cu springs that have 0.45 the electrical resistance of pure copper, this so good that you will not see any difference from a bypass, but I’m sure that the quite insignificant difference can be measured.

4

A very difficult mod but It can be done.

5

@CRX:
Beautiful!
Would like to know how you removed the switch bezel without scratches.

6

A thin tipped small flat screwdriver, slip it under the bezel and carefully twist/pry it off.
High risk of the switch boot being punctured at some point though.

7

Replacing a FET that has 1.2mOhms with anything else does make no difference
I compared the datasheet to others and did not find any better

its likely the case of the FET is the limiting factor how far resistance can go down not below 1mOhm

8

Do I understand right: you did this from the inside of the bezel, not at the outer edge between bezel and casing? I don’t mind the boot, I’ll probably go for a transparent boot anyway if I find one (I’m more capable of doing electrical mods than mechanical ones).

9

Yes mate, from the inside, placing the levering tool between the bottom of the steel bezel and the rubber.
The bezel has a lip on the top outside which you could prob get a blade under but would most likely scratch the ano going that way.
Just make sure you don’t press on the switch when prying as they are delicate.

10

Thanks for info, I’ll give it a try.