This webpage is designed to give some information and background on some of the things that we highlight as we are designing a new light.
First and foremost is the shape/size of the light in relation to the intended coverage area and height above canopy. In order to provide proper spread and even light distribution across the entire coverage area, these aspects are critical. We do not use optics as they can both cause buildup of heat at the LED/PC board junction and also are a considerable drain on efficiency since the light must travel through the optics where there is loss of transmission power.
Next is the selection of power (drivers) and wiring. We used 18AWG wire which is more than sufficient for the operating conditions of the light. Lower gauge wire has more copper conductor wiring and is generally considered safer. We always use watertight (IP65 minimum) electrical connections to ensure safe operation and to eliminate potential fire hazards. The drivers we use are solely Meanwell and Inventronics, considered the leaders in IP67 outdoor lighting power and transmission. These carry 5–7-year manufacturer warranties and are waterproof and spray safe. A good driver uses an extruded aluminum housing which further helps dissipate heat output and also provides protection from an environmental standpoint.
The printed circuit boards (commonly referred to as MCPCB or metal core printed circuit boards) are what the LEDs are mounted to. These are an often-overlooked component and should not be overlooked. Our MCPCBs used in the Magnolia and Cypress EVO lights use 4oz copper foil thickness - amongst the highest in the industry. THIS IS IMPORTANT FOR HEAT SPREADING AND IS CRITICAL FOR LED LONGEVITY. Furthermore, our LED boards are conformally coated which is a coating placed over the LEDs rendering them waterproof. This is important as water can get under components and cause rust and electrical shorts/early failure. Conformal coating differs from a glass or PMMA cover in that it has no light transmission loss and will not denature/discolor over time, especially in the presence of UV.
LEDs are what produce the light, and the spectrum output of a luminaire/fixture. Careful consideration should be taken when choosing both the number of diodes, as well as the type and brand. Samsung diodes are one of the most widely used in the world, and certainly in the horticulture industry specifically. Samsung has many different styles of diodes, but the most common is the 3030 style, named due to its size (3mm by 3mm square). Samsung has a few different models of 3030 diodes, namely the LM301B and LM301H EVO series. The LM301B came out >5 years ago and represented a leap forward in efficiency (~ 3.0µmo/J) compared to the previous models. Since then, they have introduced a newer, plantcentric series called the LM301H EVO. These LEDs are different from most all on the market in that they use a 437nm photon pump instead of the traditional 450nm. This is a higher energy wavelength thus has more photosynthetic power and is far more efficient (3.14µmol/J). These LEDs are available in 3000, 4000 and 5000K as well as a new spectrum called MINT. We use a combination of 3000, 5000 and MINT LM301H EVO LEDs to product the most efficient, and proper spectrum for full cycle usage. Additionally, it is customary to augment with discrete spectrum which emit in a specific wavelength +/- 10nm. A lot of manufacturers will add 660nm and 730nm to help boost flowering production. The amount of diodes is important as these tend to be more expensive than traditional white light diodes. More = better. The addition of UV is a simple way to get UV introduced into the grow area for plant use as opposed to a separate light requiring separate controls. We are one of the few companies to also add emerald green LEDs. The 500-530nm wavelengths of green light have been shown to aid photosynthetic power and increase biomass in the presence of high PPFD. Green has also been shown superior for canopy penetration and delivering power to lower leaf structures.
With 80-90% of the light BOM cost associated with the aspects listed above, it is customary for manufacturers to try and skimp on heatsink and frames. THIS IS A BIG NO-NO. Heatsinks are responsible for removing heat from the LED/PC board junction, rendering them more efficient and also helping the LED longevity. A proper heatsink is designed to wick heat away and also release it into the air via passive cooling. Extruded aluminum is considered the de-facto standard, although some companies use cheaper quality aluminum extrusions and even in some cases, just a flat piece of aluminum plate. Heatsinks have been shown to lower operating temps by 30-50°F compared to flat aluminum plates. A well designed light should be warm to the touch, not hot, and you should be able to comfortably place your hand on the back of the heatsink during operation. Plastic is commonly used in grow light frames and this is sub-standard compared to solid aluminum for obvious reasons. Aluminum withstands the test of time and also acts as a secondary heatsink further drawing heat away from the heatsinks themselves and thusly the LEDs in general.
A properly engineered light will also feature user replaceable parts. This enables the grower to still operate the light even in the case of a partial light outage. For instance, if a string of LEDs, or an entire bar is rendered inoperable, the remaining LEDs will take over and increase power output, keeping PPFD levels consistent and is extra important, especially during flowering. User replaceable parts also make it so the grower does not need to take down the light, package it safely (including finding the proper size box and packaging), send it in, wait for it to be fixed and shipped back. Most lights are manufactured in China making this effort much harder and expensive. We stock replacement parts in San Diego, and expedited shipping is always free. Keeping a light as close to 24/7 uptime as possible is vital, again especially during flowering.