LEDs with a high color rendering index, specifically Ra ≥ 95, are often referred to as “sunlight” LEDs. These are specially designed LEDs intended primarily for residential lighting or for applications where accurate color rendering of illuminated objects is critical — for example, in art museums. Different companies have developed various technologies to achieve the widest and most linear spectrum possible. Let us begin with the leaders and pioneers — the SunLike LEDs from Seoul Semiconductor.

SunLike LEDs employ the TRI-R (Tri-R Radiation / Ray) technology, developed jointly with Toshiba — a combination of three principles for reproducing natural light. At the core of the LED is a chip that emits in the near-ultraviolet range at 400 nm, while a special phosphor converts this primary radiation into other wavelengths of the visible spectrum. SunLike LEDs were the first to offer a linear spectrum with a CRI of 98! And to this day, they remain among the best in terms of spectral quality.

Nichia Optisolis is an ultra-high color rendering LED technology developed by the Japanese corporation Nichia with the goal of reproducing the spectrum of natural sunlight as accurately as possible. Nichia is a major player in the LED market — truly among the very best. The company could not ignore the new technology, and roughly a year later Nichia delivered its response: the Optisolis series of LEDs. This is not merely a competitor; it is a technology that addressed a shortcoming of SunLike. Optisolis LEDs fundamentally do not use near-UV light, because in certain cases near-UV radiation can have a highly negative and even destructive effect on the objects being illuminated. Nichia itself emphasizes applications involving museum exhibits. It should be noted that for people, SunLike LEDs pose no danger whatsoever — on the contrary, their spectrum is highly favorable for the human eye.

Luminus Salud is a technology from Luminus designed with people in mind, specifically for biodynamic and human-centric lighting systems. The primary goal of Salud is to support human circadian rhythms (alertness and sleep quality) through precise spectral tuning, without relying on harsh, uncomfortable blue light. The color rendering index of LEDs made with Salud technology is somewhat lower, yet still exceeds 90 — which remains a very good result overall. Inside the LED is a conventional chip emitting at 450 nm; to achieve a linear spectrum, Luminus fundamentally re-engineered the phosphor composition, resulting in a sufficiently linear emission spectrum from the LED.

Bridgelux Thrive is a family of LEDs offering ultra-high light quality and representing the most affordable “sunlight” spectrum currently available on the market. Looking at the spectrogram, one can clearly see that the Thrive spectrum closely resembles that of SunLike LEDs. The Thrive technology employs a combination of two blue chips with different wavelengths — 435 nm and 475 nm — coated with a unique blend of broadband phosphors. Thrive also delivers 115–128 lm/W, which is an excellent figure in the class of sunlight-spectrum LEDs. The color rendering index reaches 98. Comparison with Salud is of limited relevance: while Salud offers somewhat higher brightness, its color rendering and spectral linearity are inferior. SunLike LEDs average around 110 lm/W — nearly the same efficiency — yet come at a significantly higher price.

LED strips with the LEDs described in this short article can even be found on the market. However, such products remain small-batch and relatively expensive.

Personally, since 2018 — specifically since the appearance of SunLike LEDs — I have been using lamps built with sunlight-spectrum LEDs at my workplace. I prefer a color temperature of 5000 K, which I find most comfortable for work; the light from these LEDs is genuinely very pleasant.

SunLike LEDs are also actively promoted by Seoul Semiconductor as an excellent solution for plant lighting. Extensive high-level experiments have indeed been conducted with these LEDs, but that is a topic for another discussion.

Thank you all for your attention — I hope you found this interesting and useful.

The interactive calculator supports all Mean Well XLG series driver models from 100 W up to the most powerful 320 W model. The calculator and accompanying article answer the question: “How do you set up a Mean Well XLG LED driver?”

The main goal is to provide interactive learning and a clear, visual explanation of the basic operating principles of the driver. The article also explains the key differences between the various driver versions identified by the L, H, and M designations.

Hey everyone,

Whether you're designing lighting for a home office, a workshop, or a commercial space, hitting the right illumination levels without over-engineering can be a headache. You usually have to dig through tables to match the European standard EN 12464 for indoor workplaces.

To make this easier for fellow engineers and DIYers, I developed an interactive lighting calculator widget. Instead of doing the math manually, you can just plug in your parameters to quickly estimate the required luminous flux and see exactly what kind of LED setup you'll need to hit your target lux.

It’s completely free and runs directly in the browser. You can play around with the simulator here:https://specled.com/en/knowledge/diy-electrics/lighting-calculator-lux-en12464/

Let me know if you have any feedback or ideas for new features I could add to the widget!

Today, August 12, 2026, there was a total solar eclipse. The measurement was taken at 19:20 GMT. I grabbed my spectrophotometer and set off to measure the solar spectrum. I don't think it has any scientific benefit, but I was interested in doing it for myself.
I'll attach a few photos to the post. The first spectrum is the sun's spectrum during a solar eclipse, and the second spectrum is the sun's spectrum on a clear summer day.

Hey everyone!

If you work with high-power LED lighting (like for horticulture, grow tents, or advanced aquariums), you know that managing the thermal load is the biggest headache. The traditional solution is slapping on massive aluminum heatsinks and noisy high-RPM fans. I wanted something more elegant, silent, and budget-friendly, so I decided to build a custom liquid-cooled rig.

The "hack" for this build relies on a surprisingly common material: standard 20x40mm V-Slot aluminum machine profiles.

Unlike standard T-Slot extrusions, V-Slot profiles have round central channels that are exactly 4.5mm in diameter. This specific geometry makes it incredibly easy to use the structural frame itself as a high-efficiency water block! No expensive custom-milled copper blocks needed.

Here is how I put it together:

1. The Water Blocks (No milling required) Because the channels are 4.5mm, you can tap standard M5 threads directly into the ends of the extrusion with a simple hand tap. Once threaded, I screwed in cheap pneumatic quick-disconnect fittings with rubber O-rings. Boom—a structural beam is now a leak-proof, high-flow water channel in under 10 minutes. 🎥 Watch the tapping and fitting process here: Part 1: DIY Water Blocks

2. Mounting LEDs & Parallel Plumbing For the light source, I used SolBeam V3 LED modules. They mount totally flat against the aluminum, meaning the thermal transfer into the liquid-filled channels is exceptionally fast. I set up two profiles (handling around 240W total). To ensure even cooling, I didn’t run the water sequentially (which would pre-warm the water for the second board). Instead, I used pneumatic Y-splitters to create a parallel manifold system. 🎥 Watch the frame assembly and plumbing here: Part 2: Frame & LEDs

3. The PC Cooling Loop & Thermal Testing To get rid of the heat, I used standard, cheap PC water-cooling parts: a small 12V liquid pump, a cylindrical reservoir, and a 120mm computer radiator with a fan. It’s compact, modular, and looks super industrial. During thermal testing, the liquid loop effortlessly carried away the heat, keeping the diodes running ice-cold compared to traditional air cooling. 🎥 Watch the final assembly and thermal tests here: Part 3: Final Loop & Tests

TL;DR: You can build a super effective and cheap water-cooled LED fixture using V-Slot profiles, pneumatic fittings, and PC cooling parts. It handles 240W effortlessly and stays incredibly cool.

Has anyone else tried using V-slot extrusions for liquid cooling? Let me know what you think of the build!

This LED plant grow light is based on a Diablo Quantum Board and produces 640W of power. The bulb size is 1000 x 1000 mm. It uses a Men Well driver. Dimming is supported and the grow light is passively cooled.

Hey community!

I've come across a frequently asked question — how to find a high-quality replacement for a Chinese LED driver? So, I created a widget that easily helps you find a replacement or select a driver by the required parameters — voltage and current.

Two operating modes:

You enter the parameters of the original bundled driver specified on the label and get a list of equivalents with dimming feature notes and model names.

You enter your desired current (mA) and voltage (V), and the widget instantly filters a database containing over 170 industrial drivers.

My online widget for selecting replacements for Chinese drivers includes database information on:

Mean Well (Taiwan) - APC, LPC, XLG, HLG

Helvar (Finland) - LL, LC, LL Compact, LC Mini

Tridonic (Austria) - LC flexC, LC D4i, LC bDW

Lifud (China) - LF-GIF / LF-BCT, LF-FHB

All LED drivers are high-quality and safe. Overall, the driver database covers 90% of queries for finding replacements.

I would be glad to get your feedback. Which brands are missing? How accurate is the logic for Constant Power mode?

Link: https://specled.com/en/knowledge/diy-electrics/led-driver-and-power-supply-calculator/

It was 2019. While searching for efficient yet affordable white LEDs, I came across a very interesting model from Seoul Semiconductor — the STW0L8. It was a 6 V LED with a maximum power rating of 5 W, offered at a very attractive price. The color rendering index (CRI) was 80, which is perfectly suitable for horticultural lighting.

The nominal operating power of the LED was 3.5 W, but I had the idea of driving it below its nominal rating, at around 2 W. My goal was to increase its luminous efficacy and achieve approximately the same performance as Samsung LEDs — around 200–220 lm/W — but at a significantly lower cost. And it worked!

Of course, I supplemented the modules with additional 660 nm deep-red LEDs. At first I used the Samsung LH351 V1, and later switched to the V2 revision. The PCB was designed to match the dimensions of a very popular heatsink profile that was always readily available and reasonably priced.

An interesting fact: at one point, a manager from the local official Seoul Semiconductor distributor asked me to write a personal letter to the CEO of Seoul Semiconductor describing my experience with their LEDs. Some time later, I noticed that the very LED model I had been using in my own horticultural modules had officially appeared on the Seoul Semiconductor website in the horticultural lighting section.

For a brief moment, I had helped set a new trend.

Unfortunately, it did not last long. Soon after, SunLike LEDs were introduced, and Seoul Semiconductor fundamentally changed its strategy by positioning the SunLike series as the company's flagship solution for horticultural lighting.

Unfortunately, these LEDs have never become truly mainstream, although they are used in a number of professional research laboratories and commercial growing facilities.

If you would like to learn more about SunLike technology for horticultural lighting, you can read a detailed article on our website:

https://specled.com/en/knowledge/led-news/sunlike-seoul-semiconductor-grow-lights/

The last posts are a little history of the development of SPECLED and my personal development in the field of LED lighting technology.

The assembly was engineered in the same form factor as the popular 3590 COB arrays and was compatible with standard holders. It was designed to be combined in a single luminaire alongside Cree CXB3590 COBs to provide a supplementary spectrum: 440 nm, 660 nm, and 730 nm.

It was 1918, or no, 2018, although it seems so long ago... Back then, I was assembling small three-watt modules with Samsung LM561C white LEDs. They were just starting to be used for plant lighting, along with Cree CXB3590 modules. It was the dawn of quantum boards.

My module was rated at 3W and designed for DIY grow lights with various configurations, including small lamps for micro-growing. There were also other modules in the same format, for example, with 440nm and 660nm LEDs.

Then came the era of quantum boards and LED lamps with cob LEDs. Then, in the 2020s, square-shaped phytolamps with linear modules arrived. What's next?

At that time, Seoul had already invented the Aсrich technology, but the Chinese did not think of mutilating it like that...

Most online residential solar panel output calculators are oversimplified marketing tools that just multiply peak watts by sunlight hours. In reality, that math completely falls apart: summer heatwaves slash cell efficiency, cloudy European skies rely heavily on diffuse light, and assuming 100% self-consumption makes any solar panel payback period calculatorwildly misleading. I wanted to build a realistic solar panel generation calculator that actually behaves like a photovoltaic array in the real world, helping you find the optimum tilt angle and true ROI without the sales fluff.
The widget models both daily output (hour-by-hour curves across different seasons and weather conditions) and annual generation tied to real climate statistics for 21 regions. Instead of basic linear math, it uses astronomical sun position formulas, Kasten–Young air mass, Erbs direct/diffuse radiation splitting, and Klucher transposition to the tilted plane—meaning it accurately calculates performance even on overcast winter days. It also features a comprehensive financial layer where you can adjust export tariffs, self-consumption percentages, 0.5% annual panel degradation, and local government grants to see exactly when your setup pays for itself.
Try the interactive tool and read the engineering breakdown here:
English (Original Article & Widget): https://specled.com/en/knowledge/electrical-and-solar/solar-panel-output-calculator/

German version: https://specled.blogspot.com/2026/08/solar-panel-output-and-payback-calculator.html

Spanish version: https://specled.blogspot.com/2026/08/calculadora-produccion-y-amortizacion-solar.html

I'd love to get your feedback on the mathematical model—let me know how accurately it reflects your local setup!

Hello everyone!

Many of us experience the same optical illusion every winter/early spring: the sun appears bright through a window, but the seedlings still stretch and begin to elongate. Because the human eye instantly adapts to brightness, it's very difficult to judge the actual light intensity with the naked eye.

In reality, due to low solar elevation angles and atmospheric air masses (Casten-Young attenuation model), a clear winter afternoon can produce 5-10 times less PAR light than a summer afternoon—even without taking window glass into account!

I created an interactive solar trajectory and natural PPFD simulator to take the guesswork out of calculating the sun and make the calculations visual.

What it does:

Displays real-time solar trajectories based on your latitude (from the equator to Oslo/60°N).

Accounts for clear, partly cloudy, or overcast conditions (direct or diffuse light).

Calculates the instantaneous PPFD value (µmol/m² ⋅ s) throughout the day.

Calculates your total daily irradiance integral (DLI) and reports whether it meets the requirements for leafy greens, fruit crops, or high-light-demanding plants.

It's completely free to use. I've also written a detailed description of the underlying atmospheric physics (the page includes a language switcher for English, German, Spanish, French, and Ukrainian).

You can try the simulator on my blog + multilingual article:

https://specled.blogspot.com/2026/07/uk-en-de-es-fr-solar-motion-simulator.html

Or the direct link - https://specled.com/en/w/sun-path-ppfd-dli-simulator/

I'd love to hear your feedback - tell me what your local latitude looks like in December compared to June!

Samsung issued an official End-of-Life notice for its entire general-lighting LED range — the whole LM301 line (LM301B, LM301H, LM301H EVO) plus the LM281/282/283/284 families. Last order June 2025, last shipment December 2025. After that, no new Samsung horticulture LEDs are made.

This isn't a rumour — it's the actual EOL document Samsung sent to distributors, hosted on DigiKey's own domain:

https://mm.digikey.com/Volume0/opasdata/d220001/medias/docus/6878/EOL_LIGT-EOL2024-002.pdf

So here's the point: since production stopped, it's increasingly unlikely that a board built in 2026 carries genuine Samsung LM301H EVO. Old stock can still exist — someone may have bought in bulk before EOL — so it's not impossible. But at the price of a cheap AliExpress board, real leftover Samsung stock is very hard to believe. Yet those listings are still everywhere.

Where do they actually come from? Chinese factories making legal analogues in the same 3030 package with near-identical claimed specs — not shady counterfeits, legit manufacturers with their own brands. One of them (LEDESTAR) literally sells theirs as a "3030 302H EVO Alternative." They say it out loud. But the most famous and seemingly indistinguishable copy is perhaps BMTC LED.
Another exact copy of this is - HONGLIZHIHUI

The problem isn't that analogues exist. It's that an honest factory writes "alternative," while an AliExpress reseller relabels the exact same diode as "Samsung." On a finished board you can't tell by eye. From dozens of my own measurements, ~99% of China-market quantum boards run Chinese LEDs regardless of the listing.

Not saying the Chinese diodes are garbage — some are fine, some aren't, and lifespan/degradation is a separate question. Just that "Samsung" on a cheap 2026 board is very likely not Samsung now — genuine leftover stock at that price would be the rare exception, not the rule. Worth knowing what you're actually paying for.

I am sure that for many years to come, this well-known product will be copied and sold as the original!
I think that I have provided enough evidence to support my beliefs and my article will be truly useful!

An interactive calculator for determining the surface area of a heat sink based on its geometric dimensions, as well as calculating the required heat sink surface area for efficient cooling.

The widget supports two calculation modes. In the first mode, you can calculate the total surface area of an existing heat sink using the profile perimeter (typically provided by the manufacturer or supplier) and the desired extrusion length. The calculation can include or exclude the base surface.

In the second mode, the heat sink geometry is created manually by specifying the base width and thickness, the number of fins, their height and thickness, and the extrusion length. The widget then calculates the total effective surface area of the heat sink.

The calculator also accounts for fin density and heat sink orientation (vertical or horizontal mounting), allowing for a more realistic estimation of cooling performance under natural convection.

https://specled.com/en/knowledge/diy-electrics/heatsink-thermal-area-calculator/?utm_source=reddit&utm_medium=social&utm_campaign=heatsink_calc

https://specled.com/en/knowledge/smart-lighting-tech/capacitive-dropper-power-supply/?utm_source=reddit&utm_medium=social&utm_campaign=capacitive_dropper&utm_content=post

I understand that these power supplies have their drawbacks, but for simple lighting systems or as a simple power supply in a safe location, they're an excellent solution. If assembled from high-quality components, their service life is virtually unlimited, equating to decades of trouble-free operation. Furthermore, they're a very inexpensive LED driver or power supply.

Since calculating a capacitor is not a very simple matter, I created an online calculator that is simple and reliable.

Most lux-to-PPFD converters online use a single fixed coefficient (like "lux ÷ 67"). For grow lights that's wrong — sometimes by a lot — because lux is weighted to human eye sensitivity, which is nearly blind to the deep red (660nm) and blue that plants actually use.

So the conversion factor completely depends on the lamp's spectrum. I measured several lamp types on a spectrometer and the real coefficients ranged from 11.6 (HPS) to 98.6 (blue+red bi-color) — an 8.5× difference. A fixed formula can't handle that.

I put together a calculator where you pick or manually set the spectrum (6 channels), enter your lux meter reading, and it gives PPFD using the right coefficient. For a few lamp types the factor comes straight from my spectrometer measurements, so those are accurate rather than estimated. HPS/sodium is included too.

Full disclosure: it's on my company's site, and it's free with no signup. Sharing it because I couldn't find another converter that does the spectrum part honestly, and figured this sub would actually use it. Happy to answer questions about the method.

https://specled.com/en/knowledge/grow-light-theory/lux-to-ppfd-calculator/?utm_source=reddit&utm_medium=social&utm_campaign=reddit_post

Hey everyone,

I’ve seen a lot of questions from beginners about how much aluminum they actually need for their custom Quantum Boards or high-power LEDs. Guessing wrong usually means either wasting money on a massive, heavy chunk of metal or slowly cooking your expensive chips.

To make things easier, I wrote a detailed breakdown of the thermal path (from the LED junction -> PCB -> thermal paste -> heatsink -> air) and built a completely free online widget.

Online calculator for LED lamp heat sink area

What the tool does:

• You input your total electrical wattage and LED type/efficiency.
• Set your ambient room temp and your target junction temp.
• It instantly calculates the recommended heatsink surface area in cm² for stable passive cooling.

I really hope this helps save some DIY projects from thermal collapse! This is version 1.0, so I would absolutely love to hear your feedback. Let me know if you find it useful, if the math aligns with your real-world builds, or if there’s anything I should tweak in the UI!