I have a bunch of zoom lights that I have a very specific use for (What did you use your flashlight for today?)
I have been using this host: http://dx.com/192004. I chose it because it is cheap, and to be honest I didn’t know better. I wouldn’t have a problem with it for short time usage but when climbing routes like the one in my photo, these lights can be on for over an hour at a time. One of the lights got too hot and had an issue with melting.
So I’m looking at replacing the host, but would prefer not to have to buy new LEDs and drivers. The drivers I am using are Nanjg 105c 2.8A 17mm drivers. So, is there a 1x18650 zoom host that can handle the heat from XML T6 emitters with the 17mm Nanjg driver running at 2.8A?
Or should I start from scratch? Perhaps get drivers with lower max current? For these lights I do not want to run on a middle mode just to have a bright mode for other usage, I have other lights when I want max brightness. What parts should I use?
Requirements:
Zoom is absolutely a must. Being able to adjust the width of the beam to light up the climb is essential. Sometimes the lights are very close to the climb, sometimes they aren’t. I have tried diffusers on throwers and it’s not an option.
Lights need to be able to run on brightest mode without overheating until low voltage protection kicks in. Host getting warm is ok, but I do not want meltdowns.
1 x 18650 host only. I own a lot of 18650 cells so changing type is out of the question, and I really do not like multiple cell hosts… at all.
Budget lights only. 50$ lights are out of the question. These lights get hit by falling ice, get dropped and lost in old abandoned mines, dragged through caves etc etc. I’d rather have several cheap lights over one expensive light.
Not important:
Max output. Of coarse I want these lights to be bright, but reliability is more important. I’m looking for max output without overheating issues.
Throw beam. When using these lights I will very rarely, if ever, have them on the most focused mode.
To push something like that you will need ALOT of heatsinking and a solid pill, or turn down your amps...I find the XM-L and XM-L2 run very good at 2100mA and don't overheat (even in a no meat at all Convoy S2 or S5), they get warm and throw very good light but when you start approaching the max current you get more heat increase than you do light increase
I also find taking a tiny bit of NOALOX and putting it on the threads of the pill when I screw them in, it helps ALOT in wicking that heat out of the pill into the body, then natural heatsinking
Does the 503b use a P60 dropin [I know my 502B does]? And if it does have you tried the aluminum foil wrap on the dropin to wick heat away...
If your LED emitter isn't bonded to the pill you can either put a thin layer of artic silver, or silicon (yes even that stuff you put on your kitchen sink, or even two part epoxy [remember a very thin layer]) under the aluminum star against the dropin pill (hollow pills you can't bond down like this because there is nothing to bond to), then wrap the pill in aluminum foil so it has a thermal path from the dropin to the body of the host
Per this image on the DX website
The pill is solid, yes, bond down the emitter MCPCB with whatever method you choose, then NOALOX the threads to help wick heat away from the pill to the body, but at 2800mA its going to overheat fast...2100mA might overheat but it will take longer, unless you are willing to tail clicky it to a lower power mode
I think the UniquiFire UF-T20 is pretty decent for a host (not sure if it takes a 17mm driver or 20mm). See this post for pics. I think it has a really wide flood.
If your led is on a copper board (Sinkpad or Noctigon), the light can run much hotter without melting anything near the led (the temperature difference between led and shell is less with a copper board). That way you can use the light you have.
What even already might help is a better/thinner layer of thermal adhesive (Arctic Alumina/Silver Adhesive) to glue the board to the pill. Factories usually use inferior Fujik and a much too thick layer, and even sometimes there are machining bits in between pill and board that prevent a thinner layer.
The pill in the 503B hosts I have are not copper and they are hollow (nothing to glue on to). I don’t know if there are copper replacement pills for the 503B host. If not, replacing the host looks like my best option.
That host looks very nice Daylighter, although I don't think that the lens works as well as the one in the Uniquefire UF-T20, that has very good heatsinking also.
About the hollow pil: I know that there are people who disagree, but I am sure (and have experienced in some lights) that a hollow pill combined with a Sinkpad/Noctigon board, with a good and thin thermal paste/adhesive layer on the edge where the board and pill meet, has excellent heatsinking, better than many solid pills that are not machined flat enough.
The heat is still there though. The copper star makes the system more efficient shedding heat from the emitter, but it’s still pulling that heat into the pill and flashlight body. Lowering the drive current would be the only way to decrease accumulated heat over a long run time, without buying a new light.
I’ve unsoldered two of the chips and now measure 2.1A at the tailcap. The pills are hollow but I had put a washer behind the LED plate to raise it up a little in order to give it a wider beam, so I added a little thermal paste between the LED plate and washer, between the washer and pill, and a little between the pill and host. I’ll have to run a test to see how hot it will get from a fully charged battery to low voltage kick in.
In the meantime I’m ordering a T20 to run with a 2800mAh driver. I’m curios to see how it handles the heat.
You have better thermal path now, you will notice the entire head of the flashlight then down the body getting warm rather than having a scorching hot head, the better it wicks the heat away the better and more efficient the light will operate
Well, the point I tried to make: with a copper board the heat is not there: the same amount of produced heat, compared to a aluminium board with dielectric layer, is spread to the shell much faster, so the same amount of heat leaves the led behind much cooler, with the shell getting just as hot.
