There are essentially 4 XM-L2 dies on the substrate. They’re on there in a 2S2P layout, such that if you mount it on the star with positive on one side and negative on the other with the center pad as thermal path it’s a 6V configuration. But if you use the 12V SinkPAD you can keep the 4 dies divided, so that they are in the 2Series 2 Parallel form, making it work as 12V. This is pretty convoluted and seems odd to me, using the center thermal pad for ground for the two opposing emitters to tie them in. This would seem to be an on/off type set-up, unless the star is isolated from ground.
6V configuration on the left, a 6V/12V star on the right. Depending on how you set it up it can run 12V at half the amperage with this second hybrid star.
I actually did the Freebee from SinkPad, but didn’t examine them, duh. But, most members will really appreciate the effort, and so do I, thanks — good explanation
If anyone is planning to go to high amps with these emitters, I’d avoid the hybrid 6v/12v stars.
Here’s why:
I don’t like the tiny traces they used to accommodate the 6v/12v configuration on these stars. They’re really wimpy and even in the 6v config much longer than they should be.
As we’ll likely never need to run these LEDs at anything other than the 6v config in a flashlight, that makes these traces an unnecessary complication.
Shorting the LED pads out with copper strips soldered across and running 10Amps through in the 6v Config I measured a 0.124v drop across the traces!
That works out to a resistance of 0.0124Ohm, really not great. We wouldn’t touch a DD mosfet with that high of a resistance for example.
at 15A it’s 194mv
at 20A it’s 285mv (you know someone will run 20amps through one of these suckers soon enough! )
Based on this, I’d say stick with the MKR variant sinkpads (only 6v compatible) or wait for a 6v optimized noctigon with beefy traces.
When I started out on my trek to find the Ledil Seanna I was thinking I would use it with the XHP70. BUT, I think it would really magnify the artifacts in the beam. So I got a Luminus SBT-70 for the Seanna and will embark on something else with the XHP70’s I received today.
But to clarify, have a look at the Seanna sitting on top of the Courui D01 (formerly known as the Big Head)
Nice reflector Dale. l was checking one out yesterday thinking of the possibilities. The lack of weight was a real attraction. Whens the beam shots with both leds being posted?
May I ask how you got that sinkpad on the left without the extra 12V traces? I got the free samples in the mail and all mine have those crappy 6/12V traces.
Should be only a voltage drop and reduced maximum possible drive current + increased maximum dropout voltage (drops outs slightly earlier). Not the end of the world I think.
Plus a good chunk of extra heat generated right at the pcb. Those traces got quite hot even at 10amps. It’s only an extra watt or two of heat needing to be dissipated by the mcpcb, nothing tragic in a 60watt setup but still it’s another downside.
It also bugs me because it would have been so easy to make the trace length/width MUCH better for 6v, changing very little on the actual PCB.
Hmm, those traces are rather ultra thin and 1Oz copper trace weight ( 1Oz, I assume that is since that is the default in electronics, unless of course stated differently)
I don’t like it either. You won’t catch me dead using one of those 12v SinkPADs for a 6v setup, but OL is stuck and the losses are not critical, they are simply unfortunate.
As I stated elsewhere, SinkPAD is dodging a bullet here: there is no other way to achieve 12v operation on an XHP emitter with an isolated thermal pad. You can’t run 10A through the XHP70 in 12v config, you’d run maybe 5A. Losses are not as serious that way.
Personally I’m not anxious to run these XHP emitters in 12v config, it’s just not ideal for our purposes due to the wiring issue. The MK-R was better in that respect.
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