could there be negative impact from having chips which aren’t voltage matched on a board? or having boards in parallel which aren’t voltage matched? i know HLG voltage matches boards when you buy multiple but i’m not sure how big of a deal it would be if they aren’t
The b+ has the black dot
Voltage match? Do you really buy into all that have you ever worked in manufacturing? I make ar15’s upper receivers for the biggest names and not every single part is checked. That’s people’s lives on the line lol
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i’m not sure i don’t know electronics, i’m not sure how serious an issue thermal runaway is.
How would a board being 0.1v volt off cause that? I think u worry a lit to much bud
i think you misunderstood, i never said i was worried. i said HLG voltage matches boards and i’m wondering if there’s really a reason or it’s necessary
If they are voltage matched, they will all draw the same current and all the leds will shine at the same intensity. Boards that are not matched will very slightly in current draw and light intensity. I doubt it will be enough to see without using a meter, but a rough napkin guestimate says it could be as much a 5%-8% difference in lumins with a .1 volt difference in voltage.
Thats for solstrips with 8 LED’s in series, 24 volts total. I dont know how the quantum boards are wired.
oh so voltage matching is to achieve maximum efficiency, and has nothing to do with thermal runaway i guess?
my boards are 304 diodes, 2 sets of 2 in series at 120v (1400ma)
I should have put a “probably” or “Im guessing” before my statements above - Im not an LED expert or engineer, but I do have some experience with electronics, LED’s and CCCV supplies.
I cant imagine small voltage differences between the boards would make any significant difference - and it gets less serious the more LED’s you have in series. Plus, the .1 volts mentioned above was just a guess right? We dont actually know what the voltage spread is on the boards?
Looking at the LM561C spec sheet, it looks like the max forward voltage varies from 2.6 to 2.9 depending on the bin. Within a given bin, the variation is only .1 volts. They also say the tolerance for the measurements is .1 volts - which seems hi to me for such a low total voltage. Thats around 3%. In any case, for some of these measurements, the tolerance is essentially the same as the variation within the bin - which Im not sure how to interpret except to think that the voltage specs can vary up to 3% - or would it be 6% by the time you allow for the tolerance?
I would assume they (all the mfg’s - Quantum, solstrip, etc) are using all the same bin, so that tightens up the spread a good bit.
BUT - what exactly do they mean when they say “voltage matched”? Are they actually measuring the forward voltage of the board at a given current or are they just talking about using all the same bin as being “matched”?
In any case, I dont think thermal runaway due to the normal variation is a concern. The small differences “I think” would be present would not present a threat of thermal runaway, and it gets less of a threat the more led’s you have in series.
IF you had a .1 volt difference between boards, that would be divided by the number of led’s in series.
So for quantum boards, 120 volt board works out to 40 in series. .1/40 = .0025 volts per led = not enough to worry about.
For solstrips, .1/8 = .0125 volts per led. That might make a few % difference in light output from one board to the next, but still not enough to worry about as far as thermal runaway.
For both boards, unless you are pushing them to beyond the very edge power wise, I doubt its anything to worry about.
it’s my understanding they check the forward voltage or whatever and find boards which are similar when you’re ordering multiple. i know they use all S6 but i believe there’s a combination of AZ and A1 or maybe those plus everything between? not sure how the binning works
I wonder how big the variance is? That really the key bit of missing info. If its a lot larger than the .1 we are guessing, I suppose it could matter. On the other hand, if there were huge differences in series wired LED board voltages on a regular basis, I would expect mfg’s to have more problems than they do making large fixtures.
I suspect its a bit of “going the extra mile” mixed in with at least some marketing hype 
Yeah, a .1 volt change on a single LED is significant, but across a series string, the difference gets reduced y the number of leds.
Where that would come into play is if you are driving them near the max voltage.
For example, if one board had all LED’s rated for 200ma at 2.9 volts and your driver was set to deliver 2.9 volts, then if you had a second board that was rated to deliver 200 ma at 2.6 volts, that second board would be over driven. That assumes parallel boards.
I have no idea how much difference in current that would produce - they dont list specs of over driving them, but it would put you in risky territory.
BUT - that should only happen if you are mixing the lowest bin with the highest - I think.
New batch of SolStrips arrived today. Looks like the drought in 3500K LM561C chips is over…
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