LED Grow Light Efficacy
Maintaining Consistent Light Efficacy
Efficacy is one of the main statistics that professional growers will use to weigh horticultural lamps when they are considering their purchase as given that the spectrum, PPFD footprint and logistical efficiency is suitable then the electrical efficacy becomes an important factor when making a decision on which lamp to purchase.
Efficacy is measure in µmol/j and levels of 2µmol/j or greater the current standard for high power applications.
How can higher efficacy help your grow room:
Lower electrical cost.
More gpw.
Lower cost installation.
The important thing to consider when looking at the efficacy of a lamp is whether it is:
True Efficacy.
Maintained Efficacy.
When looking at lamps their are what appear to be huge deviations in the efficacy described by the vendor for lamps using similar led in similar builds.
You may see some companies claim high efficacy but you need to look at the small print for disclaimers and other information, as the calculations they use are often based upon led manufacturer calculations which always bin (test) led at very low temperatures and currents that are not achievable in the grow room during 12 - 18 hours of constant use.
For example all 700 - 2000ma, 2-4v leds are binned at 350ma with junction temperatures of 25 °C in test environments which is the same as testing them at 1w with good cooling .
You will notice disclaimers such as 'When case / heat sink temperature is 25 °C' and other unreal growing scenarios:
Indoor grow rooms case will never be that cool after 30 minutes of operation but will be more like 75 - 125°C.
Greenhouse growers will find the case / heat sink can get exceptionally hot from the constant focused sun beating down upon them in the same way your car or any other metal object in direct sunlight will.
Ask to see independent photo-metric reports which describe the lamp as being in use for 30 minutes or more before testing to gain a better idea of the true efficacy, although of course this can never give you a real life greenhouse scenario efficacy on non active cooled lamps.