1w VS 3w VS 3w-3chip in LED Growing Lights
Alrighty, my faithful readers it’s time to settle a debate. Lately there seems to be a lot of confusion about 1-watt versus 3-watt LEDs. To make things even more complicated, some companies are offering a 3-watt 3-chip LED. So to clear up the confusion, let’s first take a look at each of these types of lights. After we have them clearly visualized in our minds, we’ll talk about which type is the best.
The Basics
I find it helpful to remember the basics before delving deeper. So, as a quick reminder, let’s take a look at your common lighting diode.
The above picture shows the parts of an individual diode. The chip is the part that I want you to pay special attention to.
1 Watt LEDs
A normal LED light has one chip in it. If it is a 1w LED then that chip usually delivers close to 1 watt of power (it’s not exact). More precisely, a 1-watt LED has 350 milliamperes of electricity running through it (read this if you want to learn more about watts, amperes, and volts as they relate to LED grow lights). Take a look at the illustration below.
3 Watt LEDs
High output 3-watt LED chips can handle more juice than a 1-watt chip. They typically run at 700 milliamperes (mA) of electricity. Because they have more electricity running through them they create a brighter light that can penetrate deeper into the plant.
3 Watt 3 Chip LEDs
A 3-watt 3-chip LED is a different type of animal. It is made up of three different 1-watt chips (all crammed under the same LED). In a perfect world, you would be able to run 1,050 (350mA X 3 chips) milliamperes of electricity into a 3-watt 3-chip LED. Unfortunately these chips weren’t designed to be smushed together like this. Due to heating issues and other restraints, these three chips typically take in about 550 milliamperes total. That means each 1-watt chip is only receiving 183 milliamperes of electricity (550mA / 3). Let’s take a look at what this means.
1w VS 3w VS 3w – 3 chip
Grow experts agree that 3 watt LEDs have more power and provide deeper penetration than 1 watt LEDs. For this reason more and more grow light companies are now coming out with high output 3-watt lights. Due to the diffusion of milliamperes, the experts also agree that 3watt-3chip diodes are actually weaker than both 3-watt and 1-watt LEDs. The 3 chip lights might put out a lot of light up close, but they lack penetrating power (as shown below).
Below is a great video that shows how normal 3w diodes provide more intense light than 3w-3chip diodes.
The 1w Diodes Still Have Their Place
We just learned that the high-output 3w diodes have more penetrating power. This is really important when dealing with taller plants (over three feet tall). However, for shorter grows, a 1w diode grow light will do just fine. In fact, in some cases it may be preferable.
One advantage of the 1w light over the 3w light is efficiency. A 1-watt diode actually draws around .85 watts of power. A 3-watt diode only actually draws around 1.6 watts of power. 1.6 is greater than .85 but not on a three to one basis.
Conclusion
As is usually the case in real life, there is no clear winner. 1-watt diodes are more efficient and 3-watt diodes penetrate deeper (don’t touch 3 watt 3-chip diodes). If you want to play it safe go with a light made up of 3-watt diodes. Your plant will thank you for it.
Thow away wattage and look at light density. Why? Because penetration depends on how strong the light source is – the light density. This also means that in a perfect world where you stack LEDs side by side the choice would be obvious, you would design or buy a grow light with 3 watt LEDs stacked as close as possible.
But you also have to consider efficiency and heat dissipation. Except for blue, a typical 1 watt one color LED puts out 40 – 50 lumens of light while a typical 3 watt one color LED puts out 90 – 120 lumens. That’s only 30 – 40 lumens per watt for the 3 watt LEDs. In other words 1 watt LEDs are 33% more efficient than 3 watt LEDs. And where where does all of that 3 watt LED wasted power go? Heat!
For a grow light to run very long you must use a heat sink and all heat sinks are rated by thermal resistance (C/W). In laymans terms a typical 1″ X 1″ heat sink can only dissipate so much heat before it’s overloaded. And if you were to load 3 watt LEDs or even 1 watt LEDs side by side & top to bottom the heat would overload your heat sink, or at least any heat sinks I’ve tried.
And this brings me to the rest of my argument. Assuming the heat sink design is the limiting factor for a matrix of LEDs means you can only dissipate so many watts of heat per square inch of heat sink. Earlier in this posts I mentioned that 3 watt LEDs create more heat because they are less efficient than 1 watt LEDs. And since 1 watt LEDs are about 33% more efficient than 3 watt LEDs you can mount more 1 watt LEDs per square inch than 3 watt LEDs for a given heat sink. And the higher density 1 watt LED mounting translates into stronger light density oer sq inch from the plant light!
So, which is really better? Forget the wattage quotes from the manufacturers, they are just trying to justify what they used in their designs, Use what works best for your grow, or better yet read the reviews on this site.
Thanks Tom,
I always appreciate your thoughts. They add a lot of value to the community.
Stop by whenever you want.
Nate
Thanks Tom:
I will add this page as a link on my web site! Been getting tired of explaining this to people over and over! 🙂 My Hornets are my Medical grow lights and I tell people over and over 1w rules for Scrog and sea of green! You get twice the leds and you can choose the led angle, people tend to forget about the led itself and they all think you need lenses just not true.
Sincerely: Brian S.
How deep is the typical penetration of a 1w 470nm, 1w 66nm, 3w 470nm and 3w 660nm? My pants typically grow to 16″ tall max using a SOG setup. Will 1w diodes penetrate that deeply (efficiently) or would you recomment 3w for this task? Thank you for your time.