Polished S41s, H17F+, High Current, High CRI
H17F+ Driver:
Hello Friends! Wow, look at me!!! I've got a treasure that has yet to be announced! It's the first of its kind and I have it in my possession. It's advanced, it's efficient, it's powerful and it's genuinely "cool". It's a Dr. Jones designed driver with thermal regulation, efficient low modes and Direct drive fet. It's the H17F+. Yes, the "+" is not a typo, it's new. It's the successor to the coveted H17F driver that some have reviewed already. Dr jones released the h17f and it has been well received by the members of the Blf community. For a while, Dr Jones was somewhat of a legend here. He is known to develop advanced user programable firmware, but for a year or so his voice was quiet around here at Blf. So when he started posting again, he showed his face in good fashion living up to his praised history at Blf. He's been gone for a while again now, but maybe when he stops by again he will show up with another announcement?
H17F+ driver. Notice the size of the upgraded FET.
I've been wanting to build a unique light that would be desireable by those that appreciate flashlights. In other words, all of you and none of those around me. :-) Yes, i know that the s41s is anything but unique, but i plan to pay attention to detail and make the light special. I plan to use the best of all my supplies and even ordered NoOxiT Red and Gold to lubricate and protect every contact point in the light. The battery contacts, driver/retaining ring contacts and the copper threads will get the Gold treatment and the stainless threads get the Red. The orings will be treated with a gun care lube that I really like. It dries to a light film and lasts a while.
The most unique and exciting feature is the use of this high powered H17F+ talked about above. As far as i know, this is the only H17F+ driver that Dr. Jones shipped out. It was a gift in response to some trouble i had with his rgbw drivers. He sent it along with an rgbw replacement to compensate for my troubles. It really was no trouble at all. It was just part of the experience as i was just getting into modding and was enjoying the problem solving.
Stock light as seen on freedailydeals.com
S41s Polished to a Shine:
I received this light and as I pulled it from the package I know it was a special light. I mean, stainless and copper together on the same light. How could this go wrong? Well, aside from the light dropping down and shutting itself off after just 20sec on turbo. I wasn't bothered as I knew the driver was not going to stay.
It's a beautiful light to see and a solid light to hold. However, I noticed right off that I was not going to be satisfied with the finish of the copper and stainless. Don't get me wrong, the light is nice as but I saw potential for something special and inspired by the builds of CRX I began to polish the light.
This was the tailcap before filing and an image stolen from freedailydeals.com to show what the machine marks looked like before polishing.
I started by filing down the very aggressive knurling. I did this by rigging up one of my old drills. I clamped it in a vice and connected it to my dps5015 power supply. (Thanks TA) I then gutted out a mini trim paint roller and the roller plugs pushed perfectly into the battery tube. I put the end of the rod in the chuck, set the dps to 10v and let it spin.
Well my old dewalt only lasted about a minute. I'm sure it's the brushes. It had been making some good sparks on startup so I knew they were bad. Good thing I like junk as I dug up another rigid drill. The rigid did fine and spun as much as I needed without problems.
This is my crude setup using the drill, a hobby vice, and the DPS power supply.
It didn't take too much filing but my file was nice and sharp. Using a dull file on knurling will cause the points to fold over and you'll have a heck of a time trying to clean out the groves in the knurling. In fact, you're going to have a heck of a time filing and polishing the knurling anyway so maybe it doesn't matter. I used a file, sandpaper and a dremel to polish these groves. It was a pain but it turned out ok.
I filed the included short tube as well as long tube purchased separately.
I did a lot of polishing by hand as I love the look of it. It's a different look than machine polishing and I think it adds a look of luxury. Those of you who polish knives and handguns will know what I'm talking about. I took off all machine marks and spent some good time on the tailcap. I really liked how the edges turned out smooth and rounded yet still clearly defined.
The hand polished tailcap with machine marks removed.
The copper was the most exciting thing to polish. I love the look of polished copper! The copper did not take nearly as much time, but it's also much easier to mess up. Fortunately it went well. I first used a number of sandpaper grits on a stick cut to fit the groves. Then using a rope with compound I was able to get them to shine. The rest of the copper was sanded, polished with compound and a microfiber cloth, then rubbed with nevrdull polish. This stuff brings out the deep colors and creates the mirror like finish. It should also protect the copper from dulling for some time.
Beautiful deep-glowing copper!
In the Tail:
I planned ahead and figured if this thing is going to be pulling 10+ amps, I don't want that little omten switch to melt down on me. So I opted for a bigger omten switch with 1/3 the resistance. It was a very tight fit and required some milling with the dremel to create slots for the switch contacts on both ends. I left the contact lead that is to connect to the body unshielded from the wall of the cap. This gave a direct connection as well as the connection through the switch board for as little resistance as possible.
The new switch was a tight fit!
I installed a lighted tailcap using piolotdogs switch board and 6x led ring. The leds are pink because I like pink lights. However, they glow a bit towards the purple side. I chose to use about 7k resistance to keep the current very low. I hate coming to a light just to find a dead battery! And this light doesn't have tailcap lockout because of the nature of stainless steel. I did install a small switch underneath the tailcap spring. It will turn the lights off if they are not wanted. Though the drain on the battery is only 21-34uA of current. Depending on when the tailcap was last removed. This gives a glow that is very faint but enough to see where the light is in the dark.
Six pcs pink leds on pd's led ring. A small bypass switch is installed under the spring.
I used some insulating material that i salvaged from my wife's burned out curling iron to insulate one of the switch contacts from the flashlight body. After cutting the groves in the tailcap, the contact could not touch the body but it was too close to put all worries to rest. So i potted the switch assembly with epoxy and wrapped it with the curling iron insulation. This way all wires and resistors are set in place with minimal possibilities of problems.
Thermal and electrical insulating material, potted switch, completed switch assembly, and led test.
In the Head:
To stick to the theme of keeping resistance low, 18awg wire was used to the leds and both springs bypassed with 20awg silicone wire. It was difficult to work with the larger wire. The LED leads barely fit below the opitcs but i somehow managed to get them to lay just right.
Short heavy 18awg silicone wire to the leds.
You probably noticed that there are two different kinds of emitters. There are two cree xp-g3 5700 90+ CRI and two Nichia 219C 4500k 90+ CRI emitters that combine to make a stunningly bright and vibrant beam of light. These are the latest and greatest generation of LEDs. The XP-G3 and 219C have a very similar volts forward profile and thus they can be used in parallel. They are very efficient with a very low Vf. This will allow for a lot of power to be pulled from a single lithium ion cell. Actually, I have already measured the current draw from a rested Samsung 30Q at 4.17v. The result, 21.5amps measured at the tailcap!!! That's over 70watts! Its quite amazing actually. After measuring this, i was sure glad i dedcided to swap out the tail switch for a better one.
Since the leds were reflowed onto the origional MCPCB, the origional optics were used. I polished it and did some filing to fine tune its fit. I found the shelves inside of the updated s41s head didn't allow the optic to reach all the way to the leds. This gave a tight beam pattern, but was significantly reducing the output of the light. So i filed down the underside of the optics edge to allow the optic to sit lower and the leds to fully enter the optic openings. The result was nice but a small variation in beam color could be seen when shining on a white wall. I used a piece of luminix 5deg diffusion film and the beam is now perfectly smooth with no color variation. This luminix film is up to 97% effitient at transmitting light so hardly any output was sacrificed to achieve this result. Using TA's output graphs, and accounting for efficiencies, I calculate the output to be between 3500 and 4000 lumens of 5000k high cri light out the front!!!
Heat Handling:
When I started building this light I assumed from the start that it would be a hotroded dragster. After testing and having it for a few days has shown that I was only half right. It's DEFINITELY a dragster but it's also a light that you can put out on the road with good efficiency and excellent thermal control. The PID temperature control works flawlessly. This has taken me by surprise. In fact, I assumed the temperature control wasn't working at all. INate ad the stepdowns were so subtle I couldn't tell that it was stepping down. The only way I confirmed that it was working was to put it to high, wait a couple minutes and switch it back to the highest level and observe the difference. I double checked myself a number of times because I didn't think it could work that well.
I did move the thermistor from the driver to the mcpcb. Two extra small wires needed to be squeezed up with the two 18awg leads as well. The wires were connected to the pads where the thermistor once lay. I was nervous working that close to these precious leds so i made a dam with kapton tape when i soldered each connection. It was tedious work but no leds were harmed during this exercise.
The red and blue wires in the place where the thermistor was previously soldered and the thermistor moved to the mcpcb attached with thermal adhesive. Note: here you can see the fet that was used. I have not been able to find the data sheet. I don't know if I'm reading the label correctly from this image and forgot to look it up before covering and installing into the light.
I think moving the thermistor helps much, especially over the mid modes. It eliminates the premature dimming that some experience from the the 7135s heating up. I also heatsinked these regulators as well as the fet and mcu. I annealed a piece of 12awg solid core romex wire and gave it some pounding till it was flat. I cut two pieces and glued them to the chips using AS ceramic thermal adheasive. I went ahead and potted the driver using sensor safe RVT Copper mixed with alumina oxide 2000grt. Most of the time I use silicon carbide powder or a mix of the two but this time I just used the AO. Why? IDK... I also squirted in a small bit of thermal paste to help mix it all together. The 7135s on the bottom side will be heatsink by a good connection with the retaining ring.
The driver fully heatsinked and potted.
So the heat handling is pretty good considering. You can really tell when the copper is finally saturated though. Oh boy! It works out well that the heat transfer to the stainless steel body is relatively slow. So with thermal control enabled at one of the three lowest thresholds you can turn the light in turbo and let it run. The output will slowly be reduced to a very useable output. But don't touch the copper! At first I mean, while it's reducing output the copper is too hot to touch. Just glancing the back of my finger on the copper make me cringe. It started reducing output at around a munuite, I think, it's hard to tell. Then it takes a good 3-4 mins or so for the copper to be holdable again. The stainless tube can be held all the while though. This is the behavior of the highest level with a thermal control enabled to a low setting. Of course, you could increase the threshold if you like to live dangerously.
User Interface:
I have to say the UI is smooth and easy. I really like this double tap to turbo feature. I have the light set to four modes with hidden turbo by means of the double click. It works pretty slick and can be actived directly from off as well. And of course, there is battery check and strobe modes available as well. All this can be reconfigured by tapping 8 times to enter config mode. The brightness of each mode can be selected from a ramp of moon to turbo and saved to the mode group. Modes can be added and deleted as desired. Two separate mode groups can be programmed this way and the user can switch back and forth between the two groups. This is great for indoor vs outdoor applications or it can be used for quick access to a "Muggle" mode group with reduced max output. The H17F thread will have a link to the manual and more details about the UI.
Well, i hope you enjoined this build. It was an exciting process! This light will be listed for sale shortly. Its a hard light to put a value on. Its really kind of a "market value" light. So for now, if you are interested, send a PM with an offer. This will give me an idea of the value and if i receive an offer i think is fair, the light will go to that lucky person :-)
Note: These pictures were taken and i had forgotten to polish the front of the bezel. I was going to leave the inner part matte to reduce beam reflections but i instead decided to polish it. So it is now well polish, not as shown in these photos. Enjoy!