TK's Emisar D4 review

I guess that I’m the only one that is concerned about a 6A current and 24W of heat produced in the head when the battery is reversed. Say I put in a 30Q in a D4 the wrong way, close up the tail and do not check if it works and put it away. The sustainable power for this size light is about 8W so it gets hot fast. Perhaps some part on the driver will go at some point, will it break the circuitry or will it create a dead short?

I think that it would be a good idea for Hank to address this problem.

This is already known. I didn’t know it was “just” 6A instead of short circuit. Yeah, the light protects itself, but a dangerous situation is created if you leave the light like that. I think Hank already knows as well…

You are not the only one. It was already concluded by someone here that the reverse polarity protection was a flaw, was it toykeeper??

You probably should stop doing this :smiley:

You’re not the only one. I just don’t have a resolution except to consider this one of the reasons casual users should not buy this light.

I’m actually a bit surprised 6A for 10 seconds didn’t kill the light. The driver PCB is fiberglass, right? So it’s not going to take much heat away from whatever component is soaking it up, nor get that heat to the head very quickly so a user can feel the warming, indicating that something is wrong.

An early post of TK answering (before it was know that it didn’t have protection)

Since then, it was discussed some time ago, from here onwards:

Also, TK’s post after that:

Glad I never managed to put the battery in reverse position :person_facepalming:

We’ve pretty much all known since we were toddlers not to stick screwdrivers in wall outlets. We survive those little holes in the wall, perhaps we can put a battery in a flashlight the right way…

Yeah, Neal posted that on facebook.

I don’t think he was supposed to reveal it yet… I think Hank wanted to be the one to announce his new product. But Neal can only keep a secret for about 5 seconds. :frowning:

I’m hoping to do a review soon, if a D4S shows up in the mail. I’m going on a trip soon though, so I’m not sure if there will be time before I go.

I gave Hank some emitter suggestions, but I don’t know if he’ll do what I suggested.

Specifically, I told him he could avoid the heat issues of the 90CRI 219c by using 90CRI LH351D instead. And I told him people would really like a 4500K version using two 4000K and two 5000K emitters.

I hope he’ll make that happen, but I have no confirmation about it either way.

The reverse polarity behavior was noticed fairly early on, and I notified Hank, but I don’t think he ever fixed it. It doesn’t seem damage the driver, but it can damage the battery.

It appears to be fixed in the D4S. I checked a moment ago, and my DMM measured zero on a prototype with the battery inserted backward. The same DMM measures about 4A to 6A on a D4 with the battery in backward.

First, I just want to note that iamlucky13 currently has exactly 13 posts. :slight_smile:

About the driver though, it does have some changes compared to the D4/D1/D1S. I don’t have a production model yet though, so I’m not sure what all the changes are.

It seems one change is fixing the reverse polarity protection.

Thanks for pointing out the previous discussion, I missed it at the time but this afternoon I did find a short discussion without much detail on reddit.

But is there someone with enough knowledge of the driver to point out in what component(s) that heat is generated?

The reason I’m concerned is that I have build D4 with 2700K 90 CRI 219C leds for a lighting enthousiast, but who is new to flashlights. His first question, by email, when he received the D4 that I sent him (with battery and charger) was : “what direction should the battery go?”. He luckily had some sense that he could damage something by inserting it backwards but what direction is automatic for us is clearly not automatic for the rest of the world (he is a pretty smart guy). At that point I told him the right direction and eased his mind that the D4 was reverse polarity protected so nothing would have happened anyway (so later I had to update this story for him).

Thing is that the D4 takes such good care of the battery and the heat by means of the firmware that I did not expect it to have some silly hardware flaw that instantly makes it a dangerous light for anyone not knowledgable about the background of this light (including me even so it turns out).

The guy is smart enough to after the update use his D4 now in a safe way and so am I.

I’m glad to hear that :slight_smile:

I can at least confirm that the D4S is throwier than the D4, and it has a nice beam with only minimal artifacts. It has a round hotspot, a reflector-like spill area, and then some mild extra junk outside the edge of the spill.

It also has cyan-colored aux LEDs under the optic, 16 of them, which work like tritium vials.

It’s a D4, but sized for a 26650 cell, throwier, and with some other misc improvements.

Edit: Oh, um, my prototype uses XP-L HI 3A. I’m not sure how the beam looks with other emitters.

I like that type of bling :+1:

I’m not a huge fan of trits under optics, but I like this. It can be enabled when it’s useful and turned off the rest of the time. :slight_smile:

Neat. I’ll have to never post again to preserve that match.

Oh wait. D’oh!

It will be interesting to hear about the changes once those can be shared.

Same problem as with the Haikelite SC26; now what 26650 cell should I get…?

noooice! looking forward to this. thanks for sharing

just ordered a Shockli 26650 fm Mtn Electronics for my Rofis MR70, almost ordered two anticipating the D4s.
Butt the D4 was picky about its battery fit, so I’ll wait a bit.

I have Shockli’s, black wrapped and blue wrapped LiitoKala’s and the black wrapped LiitoKala’s seem to perform best if absolutes matter. :wink:

The Black LiitoKala’s best Efests of dark and light purple, red too. As well as Gold King Kongs and orange MNKE’s and green Moli’s, KeepPower 5200’s and Basen’s…. I, uh, have a lot of cells. :blush: The discontinued orange Powerizer LiNiMnCo’s were probably the best, a short cell with high delivery. Been out of population for a while now.

I actually don’t know for sure if those will fit. I only have one 26650 cell and it didn’t fit in my prototype. But Hank tells me the battery tube has been changed to fit bigger cells. And not only is the Shockli the highest-capacity cell in RMM’s store, it’s also one of the smaller 26650 cells. So I think it’ll probably be okay.

Meanwhile, I’ve been testing with a 18650 wrapped in packing foam.

Soooo… A M44? Probably the only thing holding me back from the M43 is the firmware (and it’s not easily changed?). An M44 with D4 firmware, and with a new flash friendly driver, I wouldn’t hesitate buying another light I have no use for, lol.

I wonder if the same $40 price point will stick for the D4s?

Next up, the D1s! Well, not the D1s, but the D1s. Then the D1ss?

Received the D4 in white this day

It´s not really white, more a very light silver grey, depends a bit on the lighting conditions
and it has the grainy surface

The clip differs from the earlier version

and it fits so tight I can not move it after clipped on :open_mouth:

Black and white :sunglasses: