TK's Emisar D4 review

Ordered my second D4 with XP-G2.

219c with 20700? Sounds hot.

219c with 20700 sure sounds cool, i dont know how you guys get on with 18350 or 18500’s………….I can run an 18650 down in minutes, few lasts/step downs and the cell V is 3.6v. In fact, i tested a vtc5 2600mah cell, from cold 100% stepping down/ramping till it settled . Left it for a few mins and checked the V at 3.98v. So roughly a normal use from max output.

I have 2 spare 18650’s with me now lol

Well, the Sanyo “B” cell has some 4200mAh and does around 10A, the “A” cell is around 3000mAh and does much more current. So I was thinking the high capacity B cell might be appropro

Dale I had zero doubts that this light would finally suck you right in. It’s hard to resist an awesome light, sold by Richard, tinkered on by TK, and created by Hank and Tom. That mix of ingredients leads to an awesome light any day of the year. It doesn’t matter how many of these hot rods you have cranked out over the last several years, just hard to resist when a new one with high quality and minimal price like the D4 comes within arms reach. It’s instinct really, we can’t be blamed for what nature makes us do.

10a would help control the crazy heat a little(may get another 5 seconds!) but seriously 4200mah in the tank is super useful……………i like the idea!

Now we just need to convince International Outdoors to sell us some 20700 tubes. With knurling. :stuck_out_tongue:

Happy belated DB

Uh, well…. I got the D4 bored for the 20700. (first time to work on the lathe after surgery, it’s 104º in the shade, no air movement at the lathe at all)

Even using the Sanyo “B” cell it’s drawing 19.54A at the tail! :open_mouth:

In case anyone’s interested in more theory here, here’s a rough comparison of FET + 1 vs a FET + 8 + 1 driver (numbers from a quad 219C D240):

At 1000 lm:
1000lm / (300 lm / W) = 3.3W

FET + 1: Efficiency of 64 lm / W > 1000 lm / (64 lm / W) = 15.6W - 3.3W = 12.3W of waste heat
FET + 8 + 1: Efficiency of 113 lm / W > 1000 lm / (130 lm / W) = 8.8W - 3.3W = 5.5W of waste heat

That’s LESS THAN HALF as much heat using a FET + 8 + 1 driver.

At 1400 lm:
1400 lm / (300 lm / W) = 4.7W

FET + 8 + 1: Efficiency of 82 lm / W ==> 1400 lm / (82 lm / W) = 17.1W - 4.7W = 12.4W of waste heat

If a FET + 1 driver was thermodynamically was stable at 1000 lm, then a FET + 8 + 1 driver should be stable at 1400 lm.

Any pictures of your setup on boring it? I recently got a lathe and need all the ideas I can get!

Might need to customize the firmware. All excessive current problems could be easily solved if you could limit the maximum output to, say 70% max FET.

Even better would be if the user could manually set the max turbo setting, like can be done with the H17F.

I hadn’t used my lathe for months, slipped 2 discs in March and pinched the radial nerve in my left arm, had surgery June 22 and am still under Dr.s orders …. I asked about operating the lathe and he cautioned me to watch for issue and stop short. That said, my lathe is in a 44 year old shop that’s attached to a barn, it’s filthy in there! As a photographer, my gear don’t go where the lathe is! lol Sorry.

Just used a boring bar and made small passes, kept it to what would just allow the Sanyo B cell to fit, Efest high discharge cells won’t go in it. I wasn’t thinking or I wouldn’t have started it. The longer cell needed a spacer between the tube and head. This removed tube contact from the driver, so I had to put solder blobs on the driver ground ring then file them to clear the fat cell. Also had to remove the spring from the driver. And then I had to address the tail cap, solder blobs around the ground ring so the tube would contact. The spring is pressed flat, it’s a very snug fit without going to greater measures. I made a copper spacer ring on the lathe so I have a shiny copper ring between the head and tube on a green D4. :slight_smile:

And as it so happens, the B cell I put in it for the 19.54A reading was at 78% charge level, so … charging it and will get a new reading, try to get a lumens reading, but am heading out to a rehearsal tonight for an event tomorrow… might be a couple of days before I can get back to readings…

Once again I’m in a position of not understanding.
I charged the B cell up and tested with my bigger clamp meter, 12.92A at the tail. Tested again with my smaller Uni-T and got 12.32 (falling, hit on the cell) Then I stuck it in the light box for a reading of 3657 lumens at start, falling.

I have no idea where or why the previous 19.54A reading. Not sure how I could stuff that up, but there it is.

Sorry about that. I find it kind of nice sometimes and kind of annoying at other times. With no clear right answer, I left it as-is. It’s easy to change in the firmware though, if you want.

I wasn’t really expecting this thread to hit four digits. It’s not a big long group project like the Q8; it’s just a review and a few days worth of development. Was planning for most of the discussion to happen in Hank’s D4 thread, but he was having difficulties with the Great Firewall of China and couldn’t post for a while.

I really appreciate the feedback everyone has given though. At least half the things I changed were because people made requests. Like, I hadn’t really considered adding a channel-switch blink, but it was a good idea that I find useful.

As it turns out, I’m in the middle of building a color quad light… but not with a FET. It’s using a dozen 7135 chips instead. It’s only 1A per emitter, but that should be plenty for my purposes.

I expect a FET might make magic smoke.

I’ve been meaning to measure that for, like, years. Thanks!

That’s kind of what the FW3A is about. The D4 might not have quite enough room (depth) for 7135 chips on the back side of the driver. It would be nice to have FET+N+1 instead of FET+1, but I find most of my use is on just the +1… so it’s mostly a theoretical upgrade for me.

I’m definitely not the type who goes through multiple 18650 cells in a single night. Usually it takes me at least a month per charge, even on 1xAA or 1x16340 lights.

I require higher illumination levels TK. I, unfortunately, don’t have the extra acute night vision of a not-so-minor deity. :wink: