Recently, one of our Growcraft X6 600W was acquired by a competitor and sent to a lab for testing. Their results measured a lower efficacy than what we list on our website; we hope this is because of the discrepancy of test parameters between our tests vs theirs and not due to any intentional tampering or alteration of our product. While we don’t deny the results of their test, we also stand behind the results from ours and this article will help explain why.
Both tests were conducted at Light Laboratory Inc. in Anaheim, CA where an array of measurements were recorded. One of which being the micromoles per joule (μmole/J). A grower cares about this metric because it tells them how efficiently their grow lights convert power from the wall into photons for the plants below. Light photons are measured in micromoles per second (μmole/s) and power from the wall is measured in Joules per second (J/s). By cancelling out the common denominator of time you’re left with μmole/J.
While you can roughly calculate a light’s efficacy at home using a wall power meter to measure the J/s (1 Watt = 1J/s) and a PAR Meter for the μmole/s, the process required to precisely calculate this metric requires the light to be tested in an integrating sphere.
An integrating sphere is coated with a highly reflective surface to measure luminance, efficacy, spectrum and more from a given light source. This reflective surface paired with the geometry of the sphere “ensures that every point within a sphere receives the same intensity of light as every other part of the sphere at the first bounce,” according to page 3 of this technical guide from SphereOptics. On a small portion of the sphere there is a port where a light measuring device, called a spectroradiometer, integrates the light from the sphere and measures the output. Our lights were tested by being hung from a center mount of the sphere and exposing the light to the spectroradiometer for a duration of 1 hour. To ensure accurate measurements the lights were first stabilized for 30 minutes before commencing the 1 hour test.
Our rationale to test the single 20 and 40 inch bars, and not an entire fixture, is based on how an integrating sphere measures light when the light source is mounted in the center. When a light source is hung from the center of the integrating sphere it then has the potential to absorb some of the light that is bouncing around the sphere and, in turn, is not recorded by the spectroradiometer resulting in a lower efficiency measurement. On page 14 of the SphereOptics technical guide it states that center mounted measurements “are extremely complex as the sample is now inside the sphere and its “self absorption” now must be taken out of the measurement.” This claim is reinforced even more so in this video from Gloptic, an integrating sphere manufacturer, by explaining that “there is a significant difference between the measurement of each single LED chip and the measurement of such [complete] module” when being tested in an integrating sphere.
Since the 40 inch bar is the workhorse of the Growcraft we wanted to see how it would perform under the strict conditions of a laboratory with as little obstructions as possible. This is why we decided to test the output and efficacy of a single light bar rather than a full Growcraft fixture. Also, because the single strip is offered as its own product.
The 40 inch bar was tested in 9 different amperages ranging from 350mA to 3500mA. All of these reports have been posted on our website since the Growcraft line was launched and can still be viewed in the Lab Reports page on our site.
The efficacy of the Growcraft was calculated using the single 40 inch strip and extrapolating it to the total number of strips on each fixture using data from these test reports. Using the test results of the 40 inch strip at 2100mA the results show that the input power in Watts is 93.73W. If that value is multiplied by 6 to act as a full X6 fixture the total is 562.38W (the closest wattage to 600W from these tests without going substantially over). This same test lists the μmole/J for the strip at 2.93.
The full X6 600W is advertised lower than this value because of the efficiency of the MEAN WELL HLG-600H-48B LED Driver. On the driver’s datasheet, provided by the manufacturer, the 600H-48B model of the driver has a 96% efficiency rating at 220VAC. If the 40 inch strip rates 2.93 μmole/J board level efficacy, then with 96% efficiency of the driver, that value is lowered to 2.81 μmole/J at this same wattage.
Now, looking at the test results of the 40 inch strip at the lowest test amperage of 350mA the strip received an input power of 14.92W. Doing the same multiplication of 6 to extrapolate that value as a full X6 600W that total wattage would equate to 89.52W; nearly 3 times higher than the minimum wattage of the X6, which when dimmed using the dimmer pot, is 5% of the driver’s total wattage or 30W.
The μmole/J from this 350mA test was rated at 3.26 μmole/J for the strip and, again taking into account the efficiency of the driver at 96%, the full system efficacy is 3.13 μmole/J. This efficacy number could, in fact, be advertised at a greater value if our tests would have been lowered to an input power of 5W to align with the minimum output of 30W for the X6 600W when fully dimmed.
We understand that these calculations and test methods may be difficult to fully wrap your head around. That is why we have started building an FAQ page that will be linked to all of our product pages, and if you’re still struggling to understand our test results we can also help to further explain at firstname.lastname@example.org
We want to thank our competitor and their affiliates for testing our light and providing the community with even more data to compare when considering a grow light. What we are not thankful for is the accusations that we intentionally mislead the public, as it’s put, “turn and burn” our customers to make a quick profit.
As a matter of fact, Chilled Tech has an established foundation in honesty and transparency by offering products that helped improve the livelihood and wellbeing of the grower dating back to our first light that was sold at cost. These lights never gained a profit, yet it was accompanied by an independent lab test by the CSA Group. The goal was to provide growers an honest idea of what kind of light they were buying. Even today, we still believe in providing growers with transparency and honesty in all of our products.
Even after conveying this information there still may be individuals who disagree with our reasoning and to them we can offer the assurance that we will be conducting more tests of our lights and provide more information to our customers and to the public as a whole.
We at ChilLED are driven by quality, performance and value. Therefore, if nothing else, our competitors attempt to discredit us only helps motivate us further in continuing our quest for quality, performance and value.