Discussion
How does the supplied specification measure up to the results we are seeing?
Number of LEDs
Specified : 684
Measured :
Comments: Perfectly matches specification.
Power Consumption @ 120VAC
Specified : 224 Watts ±5% (website states 245 Watts ±5%, though)
Measured : 225 Watts
Comments : Matches specification. Would be perfect if the website didn’t claim a different number.
Additionally, the DC power measured at the power supply output was measured at 207 Watts. This is the true power being delivered to the LED array after the 92% conversion efficiency of the Meanwell supply.
Power Factor
Specified : 0.9954
Measured : 1.00
Comments : Perfectly matches specification. Measured better than specification.
Temperature
Specified : N/A
Measured : Power Supply@129.5°F (54.16°C), Heat Sink Fins@116.3°F (46.83°C), Ambient@77.4°F (25.2°C)
Comments : Good. Power supply shows highest temperature. The maximum case temperature for the power supply is specified at 90°C and the measured temperature is well within the operating range. Some regional hotspots have been noted to exist on the LED face. It is not known if the existence of these hotspots have been factored in by the engineering team or if they could pose a reliability issue.
Spectrum
Specified :
Measured :
Comments : Can’t make an exact comparison since the source data is not available. Nominal differences exist possibly due to measurement apparatus (sphere mixing vs open air) but in general these appears close enough to call this a good match.
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 : 632 or 448-500 uMol/m^2 s
Measured : 484.463 umol / m^2 s open air (400-700nm)
Comments: Here is where things get tricky. In the specification, the PPF / PPFD varies depending on where you look. They’ve performed some testing on the unit with what I believe to be an integrating sphere. 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.
So, here are a couple of notes to consider for what they’ve specified as 632 uMol/m^2 s:
It appears that the unit under test (via the integration sphere) is consuming 233.1 Watts and, as a result, will produce a higher luminous output than what we’ve experienced (225 Watts). This means that their test unit is likely running off of 277VAC as opposed to 120VAC. This produces a higher output than a US based fixture would be capable of due to the installed line cord being designed for 120 VAC. You could potentially install different cabling and supply a single phase off of a three phase drop to obtain a similar 277VAC.
Second, it appears that they’ve extrapolated the PPF from the integrating sphere measurement. E.g. by simulating the values. They’ve calculated an optimal PAR (PPFD) output by, as they’ve put it, “adjusting” the PPF measurement.
The integration sphere measured 562.88 uMol / m^2 s while the “adjusted” uMol / m^ s that simulates a measurement at 18 inches from the unit is calculated as a higher number of 632 uMol / m^2 s. I don’t really understand this calculation or the reason why the total PPF would increase rather dramatically relative to the measured integration sphere values. Perhaps Mars could provide some technical insight? I’d think this number should be more inline with the “actual” table that denotes a PPFD between 448-550 uMol / m^2 s. Somewhere around say, 494 uMol / m^2 s?
They’ve also opt’ed to use the “adjusted” value to generate what appears to be a simulated PAR map. This assumption is based on the their center point measurement matching the “Measured in adjusted uMol / m^2 s …” of 632 uMol / m^2 s.
Otherwise, the PPFD we’ve measured (484.463 umol / m^2 s) is within the PPFD listed in the “actual” table in their guide. This was measured without any reflective walls (open air) and would likely increase a nominal amount if reflective materials were employed.
I’d agree their PPF value from the integration sphere as being accurate for 277VAC, it is not necessarily accurate for the 120 and 240 VAC conditions (which they do not specifically indicate when listing the specification). Additionally, I do not currently agree that the “adjusted” PPF value or the PPFD map as being accurate simply because I do not understand how they came to this conclusion. I do agree that the PPFD values listed in the “actual” performance tables as being accurate since it matches our current experience.
PPE
Specified : 2.57 umol/J (actual table indicates range of 2.4 to 2.57). @233.1 Watts
Measured : 2.15 umol/J. @225 Watts
Comments : 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 2.15 when using the centerpoint spot measurement method with the measured 225 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 green checkmark since we are close enough for hand grenades and I can’t properly assess the accuracy.
PAR Mapping
Specified :
Measured : Not measured at this time, conflicting information.
Comments : For the same reasons as detailed in the Radiant Energy comments, it appears that Mars derived these numbers from a simulated model. What they are calling “adjusted” uMol / m^ s is based on the integration sphere PFD. As such, I do not feel this mapping would be accurate for actual use. Further, the lengthwise dimension of their map doesn’t seem to correspond to the dimensions of the actual fixture. E.g. the fixture length is 47.5 inches while the maximum length of the provided PAR map is 36 inches. Because of this, it is difficult to know what is actually being conveyed in their mapping and whether it has any relevance to the suggested bloom area of 2ft x 4ft and, likewise, the specified veg area of 4ft x 4ft.
Chromaticity
Specified : 3900K
Measured : 3750K
Comments : Same as with the spectrum. A nominal difference in the values exists possibly due to measurement apparatus (sphere mixing vs open air) but in general they appear close enough to call this a good match.
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 IP65 rating. There are three primary engineered features that address the IP-65 ingress protection
- Conformal Coating
- Watertight electrical interconnects
- IP-65 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 : 42.51 inches (1080 mm)
Specified Width :
Specified Height :
Measured Length : 42.5 inches (1079.5 mm)
Measured Width :
Measured Height (w/power supply) :
Weight :
Comments :
Warranty (click to expand)
Mars Hydro has been promoting a three year extensive warranty. Now, I’ve been around for awhile and having a warranty exclaim “extensive” seems rather vague. “Extensive” is not really a legal term so what does this really mean?
They have a flow-chart, let’s take a look :
Warranty Flowchart (click to expand)
Flowchart hyperlinked from Mars Hydro at https://www.mars-hydro.com/mars-hydro-warranty
Ah, the notice in the bottom right box of their flow-chart explains.
A unit is fully covered including shipping charges for the first 90 days. Between 90 days and 1 year, a unit is covered against defects and Mars will cover parts and repairs but you are responsible for any shipping costs. Beyond 12 months we are into DIY land where the OEM will either supply replacement parts or you can pay the full-boat for repairs. Since some of the componentry on this unit are encased in a conformal coating on a heat sinking base, it would really be an “advanced” DIY’er project to reflow an LED, for example.
Customers generally don’t like surprises. From the stand-point of a consumer purchasing a finished unit, this is really a one year warranty. Exclaiming a warranty as being extensive may actually trigger an implied warranty depending on locale. Mars Hydro should call it what it is across their marketing efforts, a one year full warranty along with a three year parts warranty. In their own specification guide that ships with the lamp (not on-line), it’s instead called a “limited 3 year” warranty.
Note: The marketing definition appears fluid as Mars seems to be updating and clarifying how the Warranty terms are conveyed. The above flow-chart is what you should refer to when assessing the manufacturer warranty claims.
Summary
This is a rather nice fixture. It is rigid, well engineered, and has a robust feel to it. The specifications provided in the shrink wrapped specification guide are relatively accurate with the possible exception of the derived PPF numbers. Subsequent “actual” single point PPFD numbers in the examples table does align with our experience.
With the IP-65 rating, we now have a candidate unit to use around the bumbling hands and spooky wet works. While, Mars Hydro has correctly specified IP65 in the shrink wrapped specification guide, depending on where you look, the marketing claims/FAQs oscillate between stating that this unit is waterproof versus not waterproof. The correct statement is “rated to IP65”. This means that the unit is not “waterproof” but, instead, is protected against water ingress by low pressure water spray.
This unit remains cool enough to handle with bare hands under moderate ambient temperatures. It’s much cooler than I would have expected overall. The Meanwell power supply is the warmest component measured. On that note, the DC power measured at 207W which exceeds the rated power of the supply (180W). This is 115% of the rated load with no dimming. Since the current (dimming) is controlled by the supply directly, I’m not certain if Meanwell has underspecified the power capability of this device but the maximum case temperature (90°C) should be appropriately de-rated to compensate. Which, Mars does with an environmental rating of 40°C maximum.
The supply dimmer is something of a PITA as configured. You’d really only be able to adjust it when the unit is off-line since it is difficult to access the controls. Or, if you were to remove the supply from the chassis and extend the cabling (which might be a good idea, anyhow), access to the dimmer would be easier and you’d save a little on any heat load in the grow area.
Personally, I would have rather seen a pigtail interconnect for an 3 in 1 dimming function allowing for remote control. An example supply with remote dimming while retaining an IP-65 rating is the Meanwell ELG-240-36AB versus the included Meanwell ELG-240-36A.
This unit produces a moderate amount of PAR useful for a 2 foot x 4 foot area with an estimated DLI of about 21 over a 12 hour period directly under the unit. Whether a DLI of 21 is sufficient will depend on your personal growing style and needs. With the rather slim profile of the unit, it would not be difficult to increase the DLI by utilizing a number of units in close proximity.
There are a couple of hotspots discovered on the face of the LED PWB but it is not known if this could indiciate a reliability concern. Reliability overall is not really known at this time but from the engineered feel of this unit, I have high hopes.
On reliability, Mars Hydro has not been without their issues in the past. They’ve purported the use of (mostly) Epistar brand LEDs in the gull wing style packaging in their past products and have been haunted by some reliability problems to include failed LEDs. It is not clear if that issue lay with Mars or the LED manufacturer.
With the newer generation Epistar LEDs in a more modern packaging on their new products, they are claiming >50K hours at >90% luminous flux output. Epistar, unfortunately, does not seem to publicly provide reliability data in their datasheets and, as such, it is difficult to confirm this claim. UV LEDs, traditionally, have had lower lifetimes than non-UV LEDs so it would be interesting to learn more on how Epistar has tackled this problem. 50K hours >90% is a heck of a long time assuming that the utilized LEDs live up to that specification at temperature. Time will tell.
Mars Hydro does provide a warranty which they have been marketing as a three year warranty. They seem to be hoping that this will convince you that their new line of products are significantly more reliable and with less risk of failure. There is some detail work here to consider, however, as the warranty really only covers costs for the first 12 months and the user would have to cover shipping after the first 90 days. Replacement parts are provided for up to three years through an RMA process if you are willing to pay for the repair labor or perform the repair yourself. If you are capable of holding a screw driver, replacement of failed components (really only the power supply) would not be difficult with the exception of the LEDs / LED assembly.
How are the economics? A similar form factor Fluence Vypr 2p which would run in the $1600 USD range is specified as producing a PPF of approximately 1700 umol/s. This is about $0.94USD per umol. The Mar Hydro is specified as producing a PPF of approximately 563 umol/s and costs approximately $260 USD. This is about $0.46. Around half the cost when simply comparing against the umols of output.
Let’s discuss PPE for a moment. Photosynthetic photon efficacy (PPE) is the amount of total photons being produced as compared to the amount of electrical power consumed. In order to accurately calculate the PPE we need to be able to capture all of the photons produced and, in order to do that, we would need a specialized piece of gear called the integrating sphere. A larger PPE number indicates a more efficient fixture where the theoretical maximum is around a PPE of 5.1. Such a high PPE is not likely anytime soon but a variety of vendors have been approaching a PPE of 3.0 for broad spectrum illumination by using the most advanced commercially available LEDs.
We should note, the majority of the measurements we’ve made in order to compare against the supplied specification are being made at the center-point of the lamp at an 18 inch distance. The center-point is an optimal measurement location since the reflectivity of the surroundings has little affect. It is also typically the location with highest amount of irradiation from the fixture. This is a fair external measurement location to compare against a specified integrating sphere measurement (which we do not have) for PPE. But…
I’ll also note, a different technique beyond the center-point measurement is employed for PAR mapping where PPF/PPFD is measured at equal intervals over the illuminated area by moving away from the center of the fixture. Such measurements gives you an averaged PPFD over the area and will typically a result in a smaller PPFD value as a whole. In such measurements, however, the environment does come into play, namely, the location and reflectivity relative to the enclosing walls. Such measurements end-up being bound to the specifics of the measurement space. We have chosen not to produce a PAR mapping (and an averaged PPFD) at this time for this fixture, in part, due to an unclear definition of this fixtures supplied PAR map along with the missing definition of the measurement space.
Back to the comparisons. For the same two fixtures, the Fluence fixture claims a very high PPE of 2.7 while the Mars Hydro fixture claims a PPE of an also impressive 2.5. As noted earlier, accurate PPE values are made using an integration sphere which I’d assume both manufacturer’s utilized. Those are optimal measurements that are generally not realizable in practical use (light is lost and absorbed by the surroundings). They do provide in the examples table (in the supplied guide) that if you were to take three of these units, the PPE somehow exceeds the theoretical maximum at an incredible 7.20 to 8.88. Mmmm, no. The math really really doesn’t work that way.
We’ve calculated an estimated PPE of 2.15 when using the centerpoint spot measurement method with the measured 225 Watts power consumption at the wall. While, this does not match the specification or the “actual” numbers, it is still a very good number. The improvement in this area is commendable. If we were to consider the actual DC power consumed by the LED array (ignoring the 8% power supply loss), the PPE of the array itself would weigh in at 2.34 (for our measured 484.463 umol / m^2 s @207 Watts using the centerpoint spot measurement). If they were to utilize OEM high bin grade LEDs from vendors such as Samsung or Cree, it could lead them to producing a unit that is in the top tier for efficacy, albeit at a slightly higher price point 
With Epistar, a PPE greater than two is still a very good number.
This is a unit that is ready to use. Despite my being picky about some missing clarity on how they specify and market this unit, I am rather pleased with this fixture and, frankly, it has exceeded my initial expectations. The daily light output for a single unit may or may not fit your needs. With the thin profile, the potential for multiple units in the same space allows for flexibility in designing your grow area and increasing the overall DLI. Particularly, if you want to push the intensity hard or plan to employ CO2. But in order for us to do that, Mars does need to correct their PAR mapping using the more realistic “actual” numbers as opposed to what appears to be derived/calculated values. They have taken some care across the board and have not skimped on some of the hidden details that I had looked for. At the listed price point, this does appear to be a worthy fixture. After some additional hands-on use, I do look forward to purchasing another.
Cheers…