What is the difference between the two?
Thanks, Jerry
Hi Jerry,
This is a question that Hank from this forum has been trying to explain to Banggood for a while now.
I don’t think I can explain it any better than him, and it is covered elsewhere in this forum.
Your best bet for a full understanding is to read through the few posts on this thread from Post #334:
Pictures to explain are located here:
My understanding is basically as follows:
The ‘Pill’ is the internal head section of the light that contains the driver board (usually +’ve battery terminal) with wires going up through the top of the pill to the PCB and LED.
- Therefore a ’Solid Pill’ is when the shelf that the LED/PCB sits on is a solid piece of metal. This allows a greater surface area to maintain direct contact with the LED/PCB (sometimes using a thermal-compound to assist), thereby allowing greater conductivity of heat for dissipation away from the head and out of the host body.
- Conversely a ’Hollow Pill’ (or “Hollow Pillow” if you’re DealMetic!) is when the shelf on which the LED and/or PCB sits, has a hole in the centre. In this case the PCB sits just on a narrow small lip/ledge around the outside edge only. If the PCB (to which the LED is soldered) is lifted slightly you can see through the hole and onto the rear of the driver board (back-side of the +’ve terminal).
- To further add complexity, sometimes the depth of the Solid metal ‘shelf’ is of different thicknesses. A 1mm thick solid section cannot disperse as much heat to the outside as say a 5mm thick shelf. This comes at the expense of weight.
- Similarly, the pills can be of different materials which are most commonly Aluminium, Copper, or Brass; each with different heat conductivity efficiencies. Apparently the Chinese language often confuses the words for Copper and Brass (G-d knows how they make their cables then?!!), leading to misrepresentation of Copper pills (better than Aluminium), with Brass.
I hope this is correct and helps explain; all my knowledge has come second hand from the much greater experts on this forum.
All the best,
Hirsh
P.S. If you understand this, perhaps you can also help explain it to Banggood!
Picture worth a thousand words. 2 C8’s from our favorite China vendors.
First up a solid pill from a c8
Next a hollow pill from a c8
i will admit to privately? being “somewhat suspicious” of the “language barrier”.
the language barrier always comes up in “accounts payable”, customer complaint departments, shipping fiascoes… curiously? it never seems to get in the way of accounts receiveable (sales)
i went thru this when i was hitting “computer shows” constantly because i was feeding myself at one time by fixing computers and upgrading them… the company has no problem at the shows… only on the rare occasion i might have to call them back for a problem.
not “understanding” hollow pill vs solid pill? i grasp that… being unable to take a picture? ehhhhhh….
Hollow pill probably transfers enough heat away from a stock poor quality LED that people making them can’t understand the need for anything better
and it’s cheaper to make them that way because um er ah.
Either because drunk guy on drill press can carve all the way through without setting a depth of cut, and drilling 2 wire holes, and cleaning up, or
someone’s walking out of the shop with fifty cents worth of aluminum scrap every day building a retirement nest egg.
And of course it’s cheaper to put the driver, pill, and LED together on a hollow pill.
No need to hire a precision worker with good vision to thread the wires through those two little holes
and, again, no need to have cleaned up the sharp edges of drilled holes that might cut through the wires.
Obviously hollow pill superior from business/beancounter standpoint.
Only use of a solid pill is — for customers like us who improve lights: put in better, hotter, brighter, different LEDs and need that solid surface instead of a hole.
Henry Ford said, “If you find you need a tool, you have already paid for it.”
Thanks very much. I understand now. I had read it so often that I wondered at the difference, and why one was superior to the other.
Many thanks,
Jerry
Because in sales if you ask is it a Cree XM-L2 or XML, they might simply say yes, or just pick one as the translation seems the same to them. But it could be XP-G, or even the wrong XM type. In sales its easier to pretend you understood/breeze past confusion and not be picked up on it.
But complaints are generally subjective. the wording follows less uniformity and may or may not use key words in the best manner. I dont doubt that some play on it, and/or maybe the better English speakers/readers find themselves moved to sales instead of CS too.
The people you request pictures from very likely have no access to any items the business sells, let alone internal components. They could be 1000 miles away across China, youre not contacting a Home Depot. They are also unlikely to dismantle a unit for pictures anyway.
My point is often problems in life are less conspiratorial than a quick glance MIGHT infer.
Sure, it never hurts to ask, and occasionally, sometimes, you get a ZeusRay.
Hollow in this case means the center is bored clear through to the emitter pcb so there is only a shelf left for the emitter to rest on and conduct heat away. Since the led is in the center of it’s mcpcb the closest and largest area of contact is exactly where the material in the hollow pill was removed, almost as bad as a p60 where the pill is only connected to the host by the reflector and a spring, neither of which has very much surface to surface contact.
Hollow seems to be cheaper because the producers can use tubular aluminum to start with instead of machining solid material to form a pill with a shelf.
A hollow pill is also easier to assemble.
Lack of thermal compound between the star and pill is another common problem. It doesn’t usually bother modders because it is easy to fix, but it reduces the output and life of production flashlights. Hollow pills can be fixed by plugging the hole, but it requires equipment and/or time and skill, because the plug must fit the pill walls well and also fit against the star well.
It is a lonely crusade, but I like hollow pills:
-a solid pill may not be flat, if the center is raised compared to the outside, or a raised edge along a wire hole causes the ledboard to be lifted a bit, the heat transfer is worse than a hollow pill.
-at moderate currents, the heat path sideways through a common thin aluminium ledboard is sufficient. I have measured the light output of a cheap sk68-clone (hollow pill, thin alu board, no thermal paste) during the full drainage of a IMR 14500 battery (initial current 1.5A), the decrease of output was fully caused by battery drainage, and while the whole body got bleeding hot, no significant heating up effect was seen in the light output.
-at high currents, you will use a copper board, like Noctigon or Sinkpad. These boards are twice as thick, and copper conducts heat twice as well, so 4 times as much heat may be produced (6A) and that does not even account for the advantages of the direct thermal path of those board (may be run hotter even).
I think that chinese manufacturers know much better with what limited heat path you can get away with no performance problems than the average BLF-member.
It looks like you are right about copper being that much better than aluminum. (But I don’t think brass is better than aluminum.)
The cooler the better, though. If the center is high, that is better than a hollow pill. If the edge is high, that is not much better than a hollow pill. I just yesterday saw heat conducting compound do a lot of good. Unless the surfaces are lapped, I think it is always needed.
No argument, I’m sure that’s correct; they know most people never modify these flashlights, and throw them away when they quit working.
The last few SK58s and #3 zoomies I got don’t even have round LED boards —- they’re modified with straight sides so the emitter and driver can be soldered together elsewhere, and someone can just pick up the emitter, rotate it so it slides through the hole in the pill, and press it down onto the ledge, press the driver in from the other side, and it’s done.
Hey, at least half or so — well, a third — of the board is in contact with the ledge. At least partially. At least the horizontal part if not the circumference. Mostly. Except where the board isn’t flat enough to contact the ledge.
Probably enough, almost certainly enough. Who’s pushing these things, anyhow? They’re for alkaline batteries, mostly.
Here’s where it’s a problem for me: 10mm square board
You guys are missing/not reading my point:
-'the cooler the better' is not true for me. If good enough heatsinking for high performance means less work, less parts and less weight, it is better than the best possible heatsinking that does not add performance.
-as you can read in my post above, my argument was not that a hollow pill is good enough for alkaline use , no, it is good enough for any hotrod mod you can think of (except when square boards are used like that obviously ;-) )
(I always like seeing a Rebel being used in a flashlight :-) )
No, if the center of a solid (but thin) pill is raised, and you are using a copper board that makes contact in the middle but is going nowhere at the side, you force the heat to use the thin aluminium route while there's a thick copper highway to the side going unused.
from trying to consolidate all ZeusRay posts
(this is the DealMetic guy who knows nothing about flashlights, but who got us a solid pill —- 8mm thick (more than a quarter inch of solid aluminum) behind the emitter.
Discussion continued toward further improvements, but somehow instead they really screwed the next several revisions up, cutting more metal out of the pill, sticking in a metal shim with the result that lights were flashing once when turned on then dead, presumably overheating but possibly the much cheaper driver they’d swapped in.
Replying in the conversation about that, the DealMetic userid (whoever that is) posted this:
It’s almost literature, along the lines of
Better cooling always helps the light output and the LED life. It may not be noticeable except with direct drive, but LEDs always work better at lower temperature.
For Flashlights or Women?
LOL
> good enough heatsinking for high performance
I want “room to move” on the worst case side rather than stopping at “good enough” — because age and experience have convinced me that “good enough” isn’t.
Ordinary use doesn’t really stress the limits, but each time I’ve had to hang a light up somewhere to illuminate an urgent or emergency situation, it’s gotten hotter than expected.
That’s things like jumping off a bus on a rainy night to stop traffic on seeing someone lying in an intersection after a hit-and -run.
Or setting up tents after arriving at a distant mountain site with a storm coming.
And those are wet breezy situations, not the extreme case.
Now think of conditions after an earthquake during hot weather ….
It’s these little lights I want most capable of being pushed to extremes, because I’ve always got one or two of them with me, to use and hand out, when I might not have a better built light.
Seriously — taking the small cheap lights by the handful and improving them for emergency handouts is what I’m thinking. I can’t afford to carry a bunch of expensive lights just in case.