Yet again, LED Grow Lights take another leap forward!
One of the general facts of life is that technology is always advancing. And this is still true of LED grow lights which continue to improve, thanks to the continuous advances made by LED manufacturers such as Osram, Samsung and Cree. When these advances are diligently used in the design of a grow light, they bring us more light for every watt that they consume, which means bigger yields, less heat, and lower running costs for the end-user.
The SANlight Q6W brings us pretty much the highest level of efficiency that is currently possible from an LED grow light. The efficiency of a grow light at turning electrical power into PAR light is measured in µmols/Joule. Please see the last section of this article for an explanation if you are interested in the science. It goes more into depth about what µmols/Joule means, and what one actually is. (For the purposes of understanding this article you only need to know that 1 watt equals 1 Joule/second. If you don’t like the word Joule, then you can substitute it for the word “Watts” and you will still get the gist of what is being said.)
High quality LED grow lights have an efficiency of around 2 µmols/Joule or more. The SANlight Q6W produces 35% more than this at an almost incredible 2.7 µmols/Joule. The SANlight Q6W uses just 215 Watts, but it produces as much PAR light as about 290 Watts worth of PAR light produced by many other LED grow lights. When any grow light is used to its best effect then the amount of PAR light it produces will roughly translate into yield. If a SANlight Q6W is used to its best effect, then the extra PAR light that it gives out for each watt of electricity brings us new possibilities in terms of yield per watt.
So, the SANlight Q6W was designed to have great efficiency, but it has many more features and philosophy built into its design. The highly efficient LEDs are built into six modules, each with their own passive heatsink – so there’s no fans to go wrong. The modules have been made to be replaceable. If, and when, even better LEDs become available in the future, it will be possible to send your SANlight to them for a factory-fitted upgrade.
The six LED modules are all fitted to a metal backbone which contains the drive unit. At each end of the backbone there is an attached tab with three eyelets for hanging the unit. Hanging it by the centre eyelets will mean the unit hangs horizontally flat. However, if you would like it to hang tilted at a slight angle then one of the outer pairs of eyelets can be used.
Efficiency and good build quality isn’t necessarily everything. The output spectrum plays a big part in the success of any grow light too.
Let’s take a look at a graph of the SANlight Q6W light spectrum output :
At first glance it looks like the spectrum output of the Q6W might be a bit unbalanced. However, it is actually well researched and well thought out. We know that red light in the region of around 600nm to 700nm is the most efficient at stimulating photosynthesis and therefore for producing yield. As most growers know, HPS lamps produce light mostly in this red region and as a result they produce greater yields than an equivalent wattage metal halide lamp (which produces much less red and a lot more light in the rest of the spectrum). This is why, after much experimentation and testing, SANlight have come up with a formula where a big proportion of the power being used is invested into producing red light.
We also know that early LED grow lights which only produced red and blue, neglecting the middle part of the spectrum (that overall “blurple” colour) reasoning that it was only necessary to provide light with the wavelengths that are absorbed by chlorophyll. Unfortunately, this tended to produce plants that looked rather stringy and somewhat sick looking. We now know that plants absorb light right across the whole PAR spectrum and need cyan, green and yellow colours to produce all the compounds needed for normal growth and overall health.
That is why, a few years ago, many LED grow light manufacturers switched over to using lots of “full spectrum” white LEDs. Indeed, the full spectrum produces much healthier and more normal looking plants, but because so much of the power goes into the middle region of the spectrum and not so much into reds, the eventual yields are not what they could be.
The SANlight does not have just white LEDs, but it utilises enough of them to stimulate good plant health and normal growth patterns but without going overboard on the number of them and therefore “wasting” too much power in this less productive region. With most of the wattage going into making those highly productive reds. It seems that SANlight’s research into the ideal spectrum for plants has paid off in spades.
The coverage of the SANlight Q6W:
This is a very flat chart and shows that a SANlight Q6W is right at home illuminating a 1 metre by 1 metre grow space at a hanging height of around 40-45cm. A lot of this is down to the secondary optics which consists of specially designed lenses under each LED. These lenses give the grow light a 90° spread angle.
Some grow light manufacturers mount their LEDs into a large frame which are designed to illuminate an area which is not much larger than the frame. This configuration may give a slightly more even spread. However, these frames are large, can look a bit clumsy, and in some cases do not suit a greenhouse installation. The SANlight Q6W is compact, convenient and solid unit that does a perfectly good job of covering its intended footprint.
In short, the SANlight Q6W is the result of cutting edge research and is at the forefront of LED grow light technology and design. If you’re thinking about switching over to growing with LEDs, it’s unlikely you’ll find anything better than the SANlight Q6W!
Something for those growers who like a bit of science!
So, what is this µmols/Joule measurement?
To understand why we use this term to define efficiency we need to define what a µmol is, and also what a Joule is.
First of all, let’s look at what “µmols” are:
The total amount of light that any light source produces is measured in something called moles. This is actually a scientific term for a particular number of particles of something. That number of particles is equal to “Avogadro’s constant” which is 6.022 x 1023 (or, put another way, is just over 6 hundred billion billion particles).
With reference to grow lights, the particles that we are talking about are photons (in the PAR region). When we refer to a mole of light, we are talking about a quantity of just over 6 hundred billion billion photons. However, a whole mole of photons is a lot when talking about the quantities of light produced by a grow light. It makes more sense for us to talk in terms of millionths of a mole, which is what the term “µmols” means.
Now let’s take a look at what a “Joule” is:
Basically, a joule is a unit of energy or “work”. There are many forms of energy. Described simply, some examples of these forms of energy are heat, radiant (such as light), chemical, kinetic (motion), nuclear, sound, and electrical. The quantity of energy, of any type, can be measured in Joules. The rate of use of energy (work) is measured in Watts. One Watt is simply the use of one Joule of energy per second.
Energy can be neither created nor destroyed, but it can be changed from one type into another. For example, a car can convert some of the chemical energy in petrol (or diesel) into motion (kinetic) energy. Unfortunately, car engines are not 100% efficient at doing this conversion, and some of the chemical energy in the petrol is turned into heat energy during the process. Nonetheless, the sum of the amount of kinetic energy and heat energy produced will be equal to the amount of chemical energy in the petrol that has been used.
Using the above analogy, the electrical power that we put into an LED will be converted into either light or heat. If a particular LED produces more total light for a given amount of electrical power than another particular LED, then it must also produce less heat than the other one too. Excess heat in an indoor grow is often problematic. So, in many cases, and for many growers, less waste heat from their grow light is a desirable thing.
So, if we find the total amount of photons produced by a grow lamp (in the PAR region) for a given amount of energy, we can get a measure of the efficiency of that grow lamp. This is why we use the term “µmols/Joule” as a measure of the efficiency of a grow lamp.