Source for high-cri high-density led strips?

Do you already have this profile?
If I had to make hi-cri hi-density strip, I would buy 219b nichias in 3S config from KD, then solder them to the copper busline, connect each star in parrallel with extra resistor (similar to 12v strips) and choose suitable size aluminium heatsink.

No, I can pick one to adjust to the needs. 219b / KD would be a great option if:

  • I wanted a very wide profile. In some cases it’s good, in some not (I don’t need a single solution for all places though)
  • I had the budget for it. That’s over $200/m, way more than I can afford.

Actually I’ve been thinking that maybe I can find some nice PCBs and solder the LEDs / resistors / regulators of my choice. Though I think I’d need a reflow oven for that, my puny Yihua may not work.

Right now I’m searching for linear COBs on Aliexpress. Some are really nice, with up to 1170x6 mm sizes I could usually do with just 1 COB per section. And profile selection would be way easier, even a frosted lens would do for a nice efficacy improvement. Also, I could make very thin lines.
But these come in CRI “60-80”
Overall, I have troubles searching for “COB CRI” on Ali. The results that I’m getting are “COB Crystal”. :person_facepalming:

Your requirments are impossible.
First of all, you need to choose illuminance you need. And calculate how much lm/m you have to use.
When you have lm/m, you can calculate W/m. Dont forget than you won t have more than 100lm/w with small leds (not hi CRI!) and 60lm/w with COBs. (Most COBs from ali are UNDER 60CRI, never use them in living place!).
After you need to remember most simple formula than I have posted several times on BLF - at least 20sq. sm per each led Watt. Surfaces that dont have direct air flow are not included, so actually profiles that are insertes into walls/ceiling etc. should be calculated as 30-40sq. sm. per Watt.

I have used regular 36 leds/0.5m strips on aluminium pcb, power consumption near 15W/m. Most people use them “as is” (without heatsink), I have bought most cheap alu profile that I don’t like (I didn’t feel it enough for strips, in my opinion they get too hot) so I added extra aluminium heatsink with ribs cutted into strips from the backside. In real life this construction gets hot but safety hot (45 degrees progile~55 degrees pcb~75 degrees leds, don’t forget that this pcbs have big thermal R). Only after this improvements Im sure in LEDs lifetime.
As you can suppose, wide alu profile is much cheaper and faster assemble (just imagine extra several kgs of extra heatsink, its cutting, glueing etc.) than my solution.
To make it budget friendly, you have to exclude buying hardware parts from china. If you will find local supplier, you will get much lower prices for profiles and heatsinks in comparation with aliexpress.
You can find bare pcbs, but most of them are made for smaller leds (2828 2835 etc.) that are not available in 90+ cri and lm/$ wont be better than nichias from KD.

I would call this high density
https://de.aliexpress.com/item/Flexible-Led-Strip-3528-240leds-m-10mm-PCB-DC24V/32585941596.html
but they are 3528, so not more output than a lower count 2835 or 5630

https://de.aliexpress.com/item/CRI-80Ra-Natural-White-4000K-Superbright-2835SMD-LED-22-24lm-led-120leds-m-10MM-PCB-5m/32686276834.html

I bet theyll never pass maukka’s cri test :smiley: .
Also, Im sceptical about flexible pcbs.

Thanks, that’s mostly what I’ve been doing except that I didn’t know how to chose a heatsink.
When you write sm you mean cm, right?
The only light that I’ve done so far sits comfortably within the limit (35 cm^2/W enclosed, but I will PWM it to way lower output, probably at most half). The next one which I intend to do soon would be much worse at about 12 cm^2/W mounted under cabinet (counting exposed surfaces). PWMed too, but not much. I’ll look into other profile options, so I’m safe…though I may have to increase height more than I’d like. I’ll think about heatsink.

And yes, I buy profiles locally, much cheaper. :slight_smile:

That’s interesting, thanks. :slight_smile: I tried reverse image search for the spectrometer results, found nothing. The date seems OK. Use of different fonts? Weird….especially as it doesn’t look like the information that they would edit.
As to dense, I’ve seen some 300 led/m strips. The leds were smaller than 3528 though.

I like the idea of having large number of small LEDs to avoid spots in the light beam.

But the supplier of the 3528 above offers all color temperatures from 2700K to 6500K plus red, green, blue, yellow with the same lumens/LED and Ra>95. :person_facepalming:
Anyway I am tempted to try the first one…

One other thing to mention today is the overall wattage of such a strip. If you are using several meters long strips the printed PCB may have problems handling the overall current. You will need additional power feed-in cables on the way. And a big power supply.

You have to use frosted transparent plactic anyway.
Yep, leds are not modern low Vf so with 12v power supply there is no much room for voltage drop. Same time traces on pcb are not thick. I wouldnt use more than 1m strip connected from the one side, or more than 3m strip connected from both sides. So you cant only connect all strips, you have to use extra thicker wires between ps and strips.
Having power supply with adjustable output voltage is usefull option, but please check resistors wattage limit before voltage regulation.

I don’t think a frosted cover will do, you need milky for that.
But you don’t need anywhere near this dense, take a profile that has 8 mm distance between the strip and the cover, 120 LED/m and you’re done.
Do note that there are milky covers that are <30% transparent and ones that are 80%, depending on how much they scatter the light and on quality. It’s worth to pay some more.

I tend to use 24V strips. Cutting sections are twice as large and PSU selection is somewhat lower, but there’s more uniform light distribution and slightly higher efficiency. Also, so far I targetted mid-end strips; resistor based, but with good PCBs.
24V is also somewhat better when it comes to controller selection; I’ve been limited by current in my next light and that’s just over 3m.
Here I have a 2m light connected from 2 side. Considering double voltage it would be your limit. I don’t see any brightness difference between the sides.

ADDED: BTW recently I’ve seen 24V strip with 7 LEDs per section (and not 6 like usual). Higher efficiency, but more vulnerable to voltage spikes. If you use good PSUs, that’s a good thing. I use medium level, so I’m not so sure. :wink:

Just that I have said it
I have ordered a ton of cheap 5m LED Stripes - mainly 5630
The ones from GREE are by far the best
https://www.aliexpress.com/item/High-Brightness-DC-12V-5630-LED-Strip-Light-Warm-White-Cold-White-And-White-5m-Roll/32647974408.html

The Cchips are really big inside and the LEDs don’t get a lot of current - so these stripes will last.
CRI at 3000 and 4000K is good and the color of the light as well.

Thanks, I have some uses for CRI80 strips too. And these are really cheap :slight_smile:

Hey, take a look at this post. There some measurements from the vendor, I wonder if it is true:

Thanks, I’ve seen this already. Sadly, they don’t offer a single strip that would be over 60 LED/m.
I consider mailing them, maybe they have it somewhere on the side…

Did you find a solution?

I installed these in my kitchen and very happy with them.

The only downside is that the driver is pwn based so taking pictures I have to be sure to use 1/60th of a second if I recall correctly.

I am very interested in this topic, as we are beginning a kitchen remodel in the near future.

Did you just use the adhesive to mount to the bottom of a cabinet, or did you mount on an aluminum strip?

456lm/ft seems like alot, do you use these at max output often, or generally dimmed?

Any idea how many W/ft for max lumens?

Can you provide any resources (links) where I can learn more about applying this product?

thanks!

Edit, I found this page which should help a bit

Hey sbslider.

My lights are about 8 ft long. I had Flexfire recommend me the correct Zurich driver for the lights given the length. I use it at full power almost all the time, especially during the day. At night, if I want ambient light, I will use the lowest setting. Not much use in between the two.

I purchased a long piece of aluminum, about 1/8” thick by 2” wide x 8’ long. I mounted the LED’s using the supplied adhesive directly onto this aluminum piece. This aluminum piece acts as a perfect heat sink so I am never worried about the LED’s overheating. I purchase the aluminum piece for super cheap from Home Depot and it even has a small lip that protects being blinded by the light if you are sitting by nearby at eye level.

The Driver is installed inside one of the cabinets that connects to the light switch. I had an electrician do this for me so I can’t comment much further.
Flexfire is very helpfull if you call them to figure out what you need. I do recommend the HIGH CRI option for sure. I went for warm white which was the closest match for Halogen/Incandescent lighting. Def a little yellow during the day when contrasting against blue cast light from clouds, but I use it more at night so my eyes adjust.

Hope this helps.

Hi Pavlo, thanks for the quick response, definitely helpful. :+1: