1st build started today Quin SST-50

[Curdog92]

I see. Thanks again. I think I will start a Mag mod to have something to work on while I'm waiting on parts for this project. (I'm getting alot of spare parts to work with as you can see in the pics.)

I do have a question regarding batteries. With a H6Flex, what battery setup would be recommended assuming the following: 1) batteries used will be protected 18650s (such as AW 3100), 2) size of battery holder is not an issue, 3) configuration (whether S/P) is not an issue (ie, I'll figure out how to make it happen both physically/mechanically), 4) the light will be primarily ran at 1.4A, 2.8A, with a 5A turbo mode when necessary, and 5) looking for a run time of at least 2 hours at 2.8A, hopefully more.

I am thinking 10 batteries (5S2P) would give me 2 hrs, or 15 batteries (5S3P) would give me 3 hrs.

Bad idea? (I take criticism well, so if this is crazy/dumb/stupid, feel free to laugh and let me know.)

Thanks!

[Microa]

The configuration in 5S may not be possible to keep the drive current regulated in the whole run time. You should consider 6S2P.

[Microa]

Sorry, I have just checked that the input operating voltage range of H6flex is 7-21V. 5S is the upper limit.

[moderator007]

I am thinking 10 batteries (5S2P) would give me 2 hrs, or 15 batteries (5S3P) would give me 3 hrs.

This seems to be a pretty close estimate to me. I agree with what Microa said in his first post above. The driver may not stay in full regulation at 2.8 amps. This maybe fine for you. It depends alot on the forward voltage of the led at 2.8 amps. Battery sag may also play a big part in staying in regulation. There's a better chance of it staying in regulation with the 5S3P pack as the more batteries in parallel the less voltage sag you will have. The current would divide out between the paralleled batteries. I have never used the driver so I can't be sure. Just reading the specs of led and driver and making a calculated guess.

[Epsilon]

When you are thinking of 5s3p, then you might want to look into dedicated Lipo packs, used in the RC world. It will be cheaper option, but also much easier. You have to buy a hobby charger obviously

[Curdog92]

Thanks for the advice. I will certainly look into that as an option. I have a 10A/30V variable power supply that has over-current and over-voltate settings that I regularly use to charge batteries.

I don't have any beamshots, but I'm still not where I want to be with throw on this project (even with the Carclo's that seem to do very well as far as ceiling bounce.) I doubt I'll be able to top the Carclo optics, but I have one more set of reflectors enroute from DX that should arrive in a week or 10 days to try.

[cmacclel]

Thanks for the advice. I will certainly look into that as an option. I have a 10A/30V variable power supply that has over-current and over-voltate settings that I regularly use to charge batteries.

I don't have any beamshots, but I'm still not where I want to be with throw on this project (even with the Carclo's that seem to do very well as far as ceiling bounce.) I doubt I'll be able to top the Carclo optics, but I have one more set of reflectors enroute from DX that should arrive in a week or 10 days to try.

If you wanted throw you should of went with a single LED and large reflector. SST-50's where never throwers due to their large die.

Mac

[Curdog92]

Yeah, I'm kinda figuring that out the hard way I thought with the much more defined ceiling hotspot, I would have better throw once outdoors, but I don't think it worked out that way...although it's hard to tell in the back yard. I need to get it out where I can really see how far it throws. Now, I'm limited to how far my extension cord/power supply will reach.

Can you guys explain what it means to lose "full regulation"? For example, if my theoretical output is 2.8A at 17.2V, and my batteries sag below 18.2V (H6Flex must have 1V of headroom for regulation), what happens? If current regulation is lost, would it then become direct drive...with as many amps as can be delivered from batteries at that point?

Another question, why does the voltage drop when the heat sink heats up? At room temperature, with current limited to 5A, the power supply delivers 17.8V. This drops to 17.2V when the head heats up to about 50C. With the current limited to 2.8A, the Voltage starts at 17.2, and drops to 16.8 at 50C. I am using very short leads (about 18 inches) and I think it's 10 or 12 ga stranded copper wire. Either case should be minimal loss in the leads.

[Epsilon]

Thats with all semiconductors: The resistance drops when the temperature increases. If you look at datasheets of the leds, you can see a graph that sets out Vf vs temperature. So that's normal operation .

About the direct drive bit, you should check the datasheet of the driver. It might be direct drive, but that's not certain .

That is what causes "thermal runaway": How hotter it get, how more current it will take from the batteries. If you use batteries with low voltage sag, they will deliver far more current than the LED can handle, thus killing the LED.

[Walterk]

Love that heatsink, very nice job

[thijsco19]

Very nice build!!
How is your flashlight? Is it done yet?
Cant wait for the beamshots.

[SikaStag]

Have enjoyed following this thread. Now looking forward to seeing it through to completion.
Congrats on an awesome first build.

[Curdog92]

Thanks for your interest. After going through several rounds of ordering, waiting, waiting, waiting on DX shipments to arrive, I now have enough reflector samples to start a flashlight farm. I became disgusted with numerous configurations that created "floody" outputs. I have an Olight SR90...I know I can't match that throw, but my standard is high when it comes to throw. I finally found a reflector that created what I felt was the best throw I could get out of this with my size limitation. The problem then became that they were about 4 mm to large to fit my placement of LEDs on the heatsink. After ruining several trying to trim 2mm from each side on an exact angle of 72 degrees, I finally figured out how to accomplish this on a mill. This photo depicts my dilemma...you can see how terrible the reflectors look trying to create this trim by hand using a disc sander. I am currently awaiting another order of reflectors from DX. Hopefully I can get this right, then offer up some beam shots.

[Curdog92]

In the meantime, I have continued to lurk here, while completing a couple of mag mods that I ended up giving away to friends. My only other creation from scratch that worked quite well is an IR thrower that I now use frequently with 1st Gen night vision. Although difficult to hold (night vision in one hand, IR light in the other), it works great out to about 200 yards with clear visibility. Will light up eyes at 300+ yds. The built in IR is only good out to about 50 yds, so this is a remarkable improvement. Build is quite simple, DX reflector, LED Engin LZ4-R400 10 Watt IR LED, 2 18650 batteries, direct drive. I haven't seen much interest in IR here, but would be glad to post more details if someone is interested. Here's a photo with SR90, RRT 3XML, and TK35 in comparison.

[Hoop]

This build is always fresh in my mind Curdog. Keep up the good work. Also, you could use Ahorton aspherics in place of reflectors, as an alternative. I imagine you would handily beat the sr-90's throw with those. I have an sr-90 also by the way.

[Gunner12]

Amazing work. Looks really clean and all that copper should take heat away quickly.

[bshanahan14rulz]

Best "noob" thread ever! Awesome work, can't wait to see the final piece!