TK's Emisar D4 review

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.

totally, i LOVE the D4. it’s such an insane little pocket rocket. turbo is mostly for “shock and awe”. but yeah… from moonlight to like 300 lumens. it’s super useful. and the candle light and lightning settings are relaxing. LOL!

You are probably right. It definitely has the pads. Hopefully that means the later attiny chip too.

I’m guessing hank just put the V2 board in with anduril, rather than reflash an old board? If so, nice guy!

It still has that “notch” when the light switches from Regulated to FET. not sure if that means anything.

I kinda want a V2… But there’s nothing wrong with my D4.

About the thermal response, if it regulates down, that doesn’t necessarily mean it has already gotten too hot. It means that it thinks it will be too hot soon if it continues along its current trajectory, and it’s trying to “turn into the curve” to avoid overshooting.

So it can sometimes adjust down before it’s overheated… and conversely, it can sometimes adjust up while it’s still hot, if it thinks it’s cooling off too fast.

Usually this effect is only noticeable during the initial burst at a turbo level, because at that point it heats up very quickly and the estimated future temperature easily goes over the limit. It doesn’t know enough math to figure out that the temperature rise will slow down naturally on its own.

If you update the firmware though, it may behave a little better. The thermal code has been completely rewritten. It’s not perfect, but it seems to behave better and it’s a lot more stable now after it gets close to a sustainable level. Older versions could go too far, overcorrect, and bounce or oscillate sometimes… or even just randomly go on a wild tangent because of noise in the measurements.

It means it switched from regulated to FET. :slight_smile:

It’s like how, on a know to change the panning of a sound from left to right, there’s usually a notch at the center point. It indicates that the adjustment just hit a meaningful level. It could be totally smooth instead, but then it’d be harder to feel where that point is.

I don’t understand the organization of Launchpad very well, but I think this link can help you find what you’re looking for:
https://bazaar.launchpad.net/~toykeeper/flashlight-firmware/fsm/changes/

And I think that’s the development branch, not the trunk. I don’t know if that makes a difference with respect to what Emisar’s ship with.

Thank you TK!

That makes sense. When I double click back into turbo after it started stepping down the first time, it stayed brighter longer once it was already warmed up.

Not sure if I’m slick enough to update the firmware. It does have the pads though.

I might just quit while I’m ahead. Turbo for me is pretty much just for shock and awe for friends. I mainly use the light from about moonlight to 300 lumens. And I find the lightning storm and candle modes really relaxing. Haha!

The turbo level on hotrod lights like the D4 is mostly just intended for burst use anyway, not sustained use. So, ideally, it should only be used for short periods before the user manually sets it back to a sane level. It only takes a moment to see what’s off in the distance, or to make people nearby go “wow”.

Flashlights have reached an odd point in their development, where “brighter” is no longer synonymous with “more useful”. For general daily purposes, usually a couple hundred lumens is enough… and beyond that, the most important traits relate to the size and shape and interface and quality and stuff like that.

Has anyone measured how many lm does D4 make with 18350 tube and XP-L HI?

I’m looking for a stainless steel lanyard ring that fits the D4 Ti. I know I probably need to sand a bit of the tail cap to make it fit, but that’s no problem. Just need one that fits the diameter or one that I can sand down to fit.

I recently lost my Zebralight SC600 Mk II XM-L2 and just discovered the Emisar lights.

Silly high turbo modes aside, does anyone know offhand if the Emisar D4 has reasonably similar run times at equivalent outputs to the Zebralight?

I believe Zebralight claims: High: H1 1100 Lm (PID, approx 2 hr) or H2 670 Lm (PID, approx 2.5 hrs) / 356 Lm (3.9 hrs) / 162 Lm (11 hrs) Medium: M1 70 Lm (30 hrs) or M2 32 Lm (66 hrs) / 12 Lm (172 hrs) Low: L1 3.8 Lm (16 days) or L2 0.43 Lm (2.5 months) / 0.06 Lm (4.6 months) / 0.01 Lm (5.5 months)

Mostly interested in the high / medium (so runtimes at around 1,000 lumens and say ~400 lumens). I may invest in the D4SV2 for the higher capacity.

The runtimes will be shorter for a given output because ZL drivers are more efficient. The D4 driver is simply burning off (ie wasting) excess voltage.

This is not a criticism of Emisar. ZL drivers are more efficient than most flashlights.

The beam profile of the D4 is very floody so you might also need a lot more lumens in a given scenario than you did with the Zebralight. Or not, it depends what you are doing.

The D4 has a slight advantage in terms of LED efficiency: it drives more leds at lower amps in a more efficient range to get to 1000 lumen. And the Zebralight will not run for 2 hours on high (H1). Your battery will be drained after 1.3 hours :slight_smile:

That is certainly the theory but I don’t recall seeing any quad or triple whose luminous efficacy stood out as being impressive. Maukka has tested a few.

In general, ZebraLights are the most efficient on the market. Nothing else produces as many lumen-hours per charge. So the question really should be how much difference will there be.

The D4 is a FET+1 design, which has okay efficiency on the “+1” part and lower efficiency on the FET part. So it’s okay up to about 140 lm, and then efficiency drops above that.

The KR4 is more efficient since it’s regulated up to 5A… but it’s still not as efficient as a ZebraLight.

The biggest differences, though, are other traits. SC600 vs D4 have very different beam profiles, with one being throwy and one being floody. They have very different color temperatures and tints available. They have differently-shaped hosts. And they have very different interfaces and feature sets.

If you want something similar to a ZL, you might find the YLP Unicorn interesting. It’s not a SC600, but it’s similar to a SC64.

Or if you want something with a lot of throw, perhaps try a Noctigon KR1. It’s quite a bit more throwy than a SC600 XM-L2 though. So it’s not great for seeing things up-close, but if you’re mostly looking into the distance it’ll be significantly more efficient than a SC600 since it doesn’t need as much power to reach the same amount of candelas.

Thank you!

I think in practice you’ll only obviously notice the runtime difference much in two situations:
-Not changing/charging the battery in your light for literally weeks/months at a time and using lower modes most of the time (or leaving the light on in firefly while on your nightstand, etc. every night)
-If you’re frequently using output at ~1000lm or above, but that’s as much due to sheer current draw as it is lower driver efficiency

Yeah. A single 18650 cell, especially a 3500 mAh one, generally runs more than long enough unless you’re a night guard walking around for 40 hours a week with the light set to a pretty high mode.

But I’m not. So I only need to charge the battery once every few months. And at that point, it doesn’t really matter if one light gets 1.3X as much runtime as another; either one is plenty. I don’t even charge or discharge my cells completely, because I don’t need the extra runtime and it’s healthier for the cell if I don’t. I usually just charge it when it gets down to 3.3V or 3.4V, and stop charging at 4.0V or 4.1V. By doing this, even decade-old batteries still work fine.

I loved this light, but unfortunately misplaced it somewhere and cannot seem to find it again.
Now i need to buy a replacement for it…