Continuation and Discussion on the Fluence Spydr 2p fixture
Discussion
How does the supplied specification measure up to the results we are seeing?
Number of LEDs
Specified : not specified
Measured : 2124
Comments: Mixture of blue / yellow / far-red phosphors.
Power Consumption @ 120VAC
Specified : 645 Watts ±10%
Measured : 663 Watts
Comments : Slightly higher than average specified but within tolerance.
Power Factor
Specified : >90%
Measured : 100%
Comments : Perfect.
Temperature
Specified : not specified
Measured : Power Supply@136.2°F (57.89°C), Heat Sink Fins@127.2°F (52.89°C), Ambient@74.66°F (23.7°C)
Comments : Temperatures are safe to the touch (ASTM C1055 <140o) with low fire risk potential.
Spectrum
Specified :
Measured :
Comments : General spectrum shape shows red and blue peaks while greens appear subdued relative to the specified graph. Fluence has been using the same graphs to describe their spectra for a number of years and, from what I can tell, they have not updated them despite a number of LED revisions.
You can find some comparative spectra for other fixtures and lamps that we’ve measured in the past, here:
Lighting Spectral Data
Radiant Energy
Specified : 1600 umols/m2/s ±10%
Measured : 1253 umols/m2/s open air (400-700nm) at 6 inches centerspot.
Measured : 1424 umols/m2/s open air (400-700nm) at 6 inches averaged.
Comments: The averaged measurement over a 4ft x 4ft area falls slightly outside of the lower-end of the tolerance amounting to a 11% deficiency relative to the specified value.The are differing definitions of flux where it is either defined as total flux or flux density, as such it is not always clear what is being referred to when stating PPF. This PPF specification was likely determined using an integrating sphere to capture the total flux without reference to area. An integrating sphere is an excellent and expensive tool for determining the total number of photons produced by a fixture. Such a test tool is used to capture ALL of the light emitted from a light source even if the photons were somehow emitted tangentially from the fixture. It is the optimal output measurement of a fixture. It is also good for measuring the overall spectrum since it, in essence, mixes the varied energy photons (colors) prior to measurement (otherwise there may be mild variations in spectra depending on the measurement sensor location). From an integration sphere you can determine the overall efficiency and spectrum but not necessarily the real world performance (amount of light in a specific direction) since the optical characteristics are not measured. For that, you’d either perform real world tests or by model simulation. Fluence does not specify measurement conditions or provide values under actual real-world conditions but has provided a fixture comparison document:
Fluence-Product-Matrix-181130.pdf (208.1 KB)
PPE
Specified : 2.5 umol/J @645 Watts
Measured : 2.14 umol/J @663 Watts
Comments : This measurement does not meet the specification. Accurate PPE values are made using an integration sphere which I’d assume is the case here. These are optimal measurements. You can expect estimating such values in the field, such as using PPFD, to be measured at something less. We’d calculate a PPE of 2.14 when using the averaged PPFD measurement for one m2 with the measured 663 Watts power consumption at the wall. This does not match the specification or the “actual” numbers but is still a good number. Since I don’t have the equipment to accurately capture the entire flux, I’m giving this a warning checkmark since the deviation could be a concern but I can’t properly assess the accuracy.
PAR Mapping
Specified : average PPFD of 990 umols/m2/s per marketing materials
Measured : 6 Inch Height
Measured : 12 Inch Height
Comments : The PPFD at 6 inches of height across a 4ft by 4ft area averages to 958 umols/m2s. At 12 inches of height for the same 16 sq. ft area, the PPFD averages to 912 umols/m2s. While the walls consist of a reflective material, there are losses involved explaining the disparity between the two heights. The measured PPFD of 958 umols/m2/s over a 4 by 4 area is less than a 3% variance from the specified value.
Fluence specifies an average PPFD over an 4ft x 4ft area at six inch distance of 990 umols/m2/s. In this case, the 64 point average over the 4ft x 4ft area produces 958 umols/m2/s. This measurement shows <3% variance from the specified value.
Chromaticity
Specified : not specified
Measured : 3613K
Comments : This unit has a very high CRI for a horticultural fixture.
Things we didn’t specifically measure but could use your help with filling in some of the details:
Ingress Protection (click to expand)
We didn’t measure against the IP66 rating. There are three primary engineered features that address the IP-66 ingress protection
- Conformal Coating
- Watertight electrical interconnects
- IP-66 rated power supply
I’m not really familiar with silicone resin / siloxane conformal coatings but I’ve noted a couple of potential advantages and disadvantages:
- Advantage : Moisture / humidity and dust protection.
- Advantage : Some protection from accidental contact with live (DC>19V) voltages.
- Advantage : Mild impact protection.
- Advantage: Relatively easy to clean.
- Advantage : Diffuses / spreads the light energy to some extent.
- Disadvantage : May absorb a small amount of the light energy. Unclear if it absorbs UV.
- Disadvantage: Difficult to DIY rework / repair.
- Possible disadvantage: Depending on the chemistry of the coating, there could be long term yellowing / hazing of the clear coating. It is also unclear if, overtime, heat will allow foreign material to bond to the coating.
- Disadvantage: While being easy to clean, it is at the same time also more difficult to clean. The surface is “grippy” and tends to hold onto particles. For this particular unit, despite having wiped it several times, dirt particles tend hang around. The particles are not bonded in place, it’s just a grippy surface.
For UV, this paper tends to indicate that most silicone resin conformal coatings are resistant to UV aging,
https://smtnet.com/library/files/upload/conformal-coating.pdf
Length and Weight (click to expand)
Specified Length : xx inches (xx mm)
Specified Width :
Specified Height :
Measured Length : xx inches (xx mm)
Measured Width :
Measured Height (w/power supply) :
Weight :
Comments :
Warranty (click to expand)
Five year limited warranty applicable to commercial sales through the Fluence internet website, or through authorized distributors or retailers:
Limited Warranty - Fluence
Summary
The efficacy numbers as calculated using the centerspot method for this unit are excellent at 2.14@663W but well below the specification of 2.5. If we consider PPE relative to the DC power (ignoring conversion loss), we see an efficacy of 2.32 at the six inch distance centerspot measurement. It is thus assumed that the specification PPF was obtained through the use of an integrating sphere which produces true values but necessarily useful values.
The measurements on this particular unit do not meet the supplied specification for PPF using a centerspot measurement at the minimum recommend distance (1600 umols/m2/s). Likewise, averaging over the 4ft x 4ft area produces 1424 umols/m2/s (400-700nm). This falls slightly below the specified tolerance. See above for notes regarding integration spheres and why this measurement may still be satisfactory.
One of the unique features of the Spydr series is that the light energy is spread out over a large area. Other units that have smaller overall footprint but similar centerspot performance numbers will fall short for uniform intensity over the grow space. We can expect a significantly more uniform intensity for this Fluence fixture over the specified footprint of the fixture.
While the specification sheet does not provide PPFD, a fixture comparison matrix provided by Fluence does note ~990 umols/m2/s on average. At the six inch and twelve inch distance, our measurements match the marketing values within a reasonable amount of measurement error, 958 and 912 umols/m2/s respectively averaged over a 4ft x 4ft area.
This photosynthetic flux is sufficient from veg to flower. At an estimated fixture distance of between six to eighteen inches, the use of CO2 may be helpful to inhibit photosynthetic quenching and to enhance carbon fixation particularly for sealed systems. Otherwise, photosynthesis at these high PPFD levels will be carbon limited at the atmospheric CO2 concentration.
The general recommendation for cannabis is that CO2 supplementation must be utilized for PPFD exceeding ~1000 umols/m2/s. At the recommended 6 inch hanging height above the canopy, this unit enters into the realm of supplementation. At 12 inches of height, this unit is knocking on the door of required supplementation. Supplementation would likely still be helpful. If you don’t have CO2 supplementation, setting the height at 12 inches or greater above the canopy or dimming the unit slightly would be suggested.
While this unit has a fairly consistent coverage due to it’s form factor, the advantage of a higher hanging height includes a more even coverage across the grow space albeit at the cost of reduced intensity.
The power supply provided by Fluence is quite large. In fact, it’s something of a nesting doll with an outer case that wraps an inner cased power supply. This is a bit unusual and I’m not certain as to the reasoning for such a design. The outer case temperature of the supply measured at approximately 136.2°F (57.89°C). The default configuration for the fixture is such that the power supply is intended to mount on top of the LED frame with a short DC cord interconnect. As usual, it’s probably a good idea to place the power supply somewhere external to the grow area to limit the additional heat load. An DC extension is not supplied but can be ordered for a nominal amount.
The supply is a universal autoranging supply which means that these units can be utilized around the world between 120 - 480VAC with the appropriate line cord.
Cheers…