TK's Emisar D4 review

[battery]

@menufunc

@djozz

@menufunc

I just got the D4. I am using Sony’s Lifepo4 batteries = SE US18650FT. Sometimes the D4 flashes three times after a few seconds when I use the turbo / 100% output, and then it SUDDENLY drops to around 1xx lumens after the flashing. But sometimes it is normal when I use turbo, it steps down gradually, not a sudden drop of output. However when I use some cheap Chinese made Lifepo4 batteries, it is 100% flashing three times after a few seconds in the turbo mode and then suddenly drop to 1xx lumens.

Does anyone know why?

I know the light should have low voltage protection but it should not activate at around 3.2V? And very strange sometimes it works but sometimes it does not when I use the Sony Lifepo 4.

Welcome to BLF

I’m not sure why you use a LiFePo battery in the D4, the D4 is designed for li-ion batteries that have a higher voltage. It is not surprising that you run in low voltage problems.

Thank you Djozz

It is because I have many of the Sony Lifepo4, I like these cells and I am still waiting for the VTC6…. :money_mouth_face: I just do not understand why sometimes it works but sometimes it doesn’t. I guess there is something to do with the temperature of the battery. Maybe when the battery is at lower temperature the voltage should be lower when the light is driven at more than 10 amps….

The driver expects IMR type cells and 3.2 volts resting (and likely lower on load) as far as its concerned is a nearly empty cell.

[noboneshotdog]

@Persechini

I too am tempted, but my spending with flashlights over the last few months has gone way over budget. Well, maybe for Christmas

PS: Green lantern is a cool nickname for this flashlight

I like Green Lantern. And HULK too!

[vwpieces]

My Black 219C arrived the other day.
Thanks to all that participated in the making of this light.
The 219C I got is pretty White, good clean white.
Wasn’t long till I swapped the optic for a Frosty 10623 Carclo Lens - 4-UP Quad Frosted Medium Spot Optic from Richard.

Also have a bad habit of holding lights in my mouth…. added an adhesive lined heatshrink to the tailcap.

[DB_Custom (Dale)]

Um, unless my Lee Filters sample is not actually the optional HT (high heat) version, I’m not going to be able to filter the light. It kinda starts smoking and melts within mere seconds. Oops! So if I want high output green, it’s gotta be the Luminus $87 emitter. :confounded:

(Edit: This was on my Titanium/Cu Quad run by an 18500)

[Wennn]

Thinking of getting one of these as a EDC + showoff light, was wondering which emitter would appear the brightest on a fully charged Aspire 18350?

I personally prefer the 6500k to 5000k tint, but at $18 more, if the Nichias are brighter (due to a lower VF and higher sag of the 18350s), that might be enough to sway me towards the 5k tint.

[ToyKeeper]

The XP-L HI should appear brightest in almost any circumstances. It has significantly higher lux than any of the other flavors.

[ToyKeeper]

@DB Custom

I’ve always dreamed of being a superhero, nows my chance to become…

The Green Lantern!

(yeah, ok, so y’all know which color I got. Maybe I’ll put a 2,000 lumen green SBT-70 in it…. )

FWIW, I had nothing to do with this light being green. I do appreciate it though.

Is BuWave still around? He was always into the Green Lantern…

[djozz]

Since his Fasttech thread was parallelled he was here less and less.

[tocirahl]

Is there any way for me to decrease the current drawn by the light when the FET is engaged? I’d like to maybe limit the light to 1500 lumens on turbo and increase the efficiency of the medium modes.

[fischju]

If you carry this light in the high pepper configurations, LOCK IT OUT. A friend of mine I bought one for lit his pocket on fire yesterday. Burned a hole through it. He’s not injured, just an idiot for leaving the memory on turbo and not using the pocket clip or lockout.

[RMM]

@ledalex

Yeah, I think something else is going on. Unscrewing the lens and moving the board with the leds results in some weird stuff going on. Maybe the driver is bad. I haven’t heard back from Mountain yet. Hopefully they respond. You would think he’d check them before sending them out. Hank, I don’t see why it would matter how good of a conductor that wire is. If the switch is working, it’s allowing enough current through.

We check all of the lights we sell; individually, not one out a batch. With something like this, however, it is possible that the light worked when we had it, but then over time the wire pinched more and started to give the fault.

We did respond with a return shipping label and offer to fix/replace the light.

[maukka]

My output numbers for the 219c version. Taken at a couple of seconds, not absolute max at turn on.

Aspire 18350: 2670 lm (1455 lm at 30 sec)
VTC6: 3100 lm (445 lm at 30 sec)
18650GA: 2760 lm (830 lm at 30 sec)

[joechina]

@fischju

If you carry this light in the high pepper configurations, LOCK IT OUT. A friend of mine I bought one for lit his pocket on fire yesterday. Burned a hole through it. He’s not injured, just an idiot for leaving the memory on turbo and not using the pocket clip or lockout.

Pictures please! :smiling_imp:

[joechina]

Green Lantern?

I thought the nickname is nutburner.

Has somebody laid corn on the lens? Will it pop?

[RollerBoySE]

@maukka

My output numbers for the 219c version. Taken at a couple of seconds, not absolute max at turn on.

Aspire 18350: 2670 lm (1455 lm at 30 sec)
VTC6: 3100 lm (445 lm at 30 sec)
18650GA: 2760 lm (830 lm at 30 sec)

Impressive, considering the size.

Have you had time to check the CRI value?

[maukka]

Nothing surprising in CRI.

Tint (a bit on the green side, but nothing distracting) stays consistent on the lower modes due to PWM.

Turbo at 5 seconds

Between 7135 100% and turbo

7135 100%

A bit above moon

[RollerBoySE]

Thanks for the measurements maukka!

Not too bad, but obviously R9080 spec. would have been even nicer.

(Yes, I would gladly pay extra for it and don’t mind losing a few lumens.)

[patmurris]

Thanks maukka, i’m expecting the exact same light.

I’m always impressed with your measurements and graphics… Is there a thread where you explain how you achieve them? - what equipment and software?

[tocirahl]

Made some interesting graphs for FET+1 efficiency (based on numbers from the Emisar D4 w/ 219C D240 LEDs). Thought you guys might enjoy them. All these are based on calculations and not empirical data, so please take everything with a grain of salt, but this should give you a rough idea of how the light behaves and how the efficiency differs between an 18350 (with a lower max output) and an 18650 cell.

Some interesting (albeit, expected) results. Efficiency is constant in the lower modes because it’s just PWM on the 7135. Efficiency is greater on the 18350 light since it draws less current when using the FET. This applies to any given brightness. What this means is that using a battery with less current handling capabilities will result in more efficient medium modes (as long as the battery is still able to handle turbo).

[Firelight2]

@maukka

My output numbers for the 219c version. Taken at a couple of seconds, not absolute max at turn on.

Aspire 18350: 2670 lm (1455 lm at 30 sec)
VTC6: 3100 lm (445 lm at 30 sec)
18650GA: 2760 lm (830 lm at 30 sec)

Nice results.

Notice how the Aspire had much greater output after 30 seconds. You can see how the temp sensor circuit kicked in a lot quicker on the 18650 cells to reduce output and might have overdone it.

I don’t think the D4 has it, but one nice feature might be to have the temp sensor step the light back up in output once temp goes down.