Of all the new lighting technologies available, double ended HPS bulbs and specifically the Gavita Pro E-Series Ballasts that drive them have garnered the most attention. Rightfully so, as these new fixtures are delivering the increased light output and efficiency the manufacturers claim. What are the key differences that set these lamps apart? More importantly, are they right for your application and is the extra performance and features worth the premium price?
These lamps are an evolutionary improvement over the traditional mogul base HPS bulb and digital or magnetic ballast. Let’s go over the three important differences of these fixtures versus a traditional electronic ballast and single ended bulb.
The main design difference in a DE bulb is that the electrode enters the bulb from each end, eliminating the need for a wire frame around the arc tube and reducing the distance that electricity needs to travel within the bulb. This also allows for a smaller diameter bulb with improved optics that can run hotter at higher voltage. These bulbs run hotter and at higher voltage, the upshot to all this is improved spectral output and efficiency.
The first thing you notice when you see this reflector is what’s missing, it’s a beautiful example of simplicity in design. It has no vent ports to lose light from, eliminating the need for a steel frame and allowing bulb heat to dissipate upward from the thin aluminum reflector. The reflector is designed to be replaced annually avoiding loss in output due to oxidation of the aluminum. Lastly, but perhaps most important, the open bulb design means there is no glass lens, which can block 5% or more of the light output from your lamp even if it’s perfectly clean.
One person can easily handle and install the all-in-one fixture, and the lack of remote ballast cord eliminates RF interference. The ability to run all of your ballasts (up to 80!) from a single EL2 Master Controller with sunrise/sunset, heat based auto dim and shutoff, and external notification (txt/e-mail/alarm) is icing on the cake.
Sounds great right? Not so fast!
Before you rush out and plunk down your hard earned green, there’s a few things to consider to determine if these lamps are a good match for your application. While very efficient and good at dissipating heat, it doesn’t magically disappear, the heat goes straight up. You will need 2-3’ open above the fixtures to provide enough airspace for them to cool properly. The next question is how to remove that heat from the grow space. Gavita’s knowledgebase recommends 2600 BTU of cooling for a 600watt Pro-line and 4000 BTU for each 1000watt. If you’re running a fresh air room you will probably need to increase the CFM of your exhaust (and perhaps size/number of filters) to exchange the air quickly enough. If you are in a sealed room with CO2 and A/C, those BTU’s add up fast so make sure your climate control is up to the task.
Okay, but are they really worth it?
The goal of this article isn’t to convince you to buy new DE style lamps, but rather to help you become familiar with the technology and be able to make an informed decision. That said, if your environment will support these lamps, it would be very difficult for me to recommend a traditional air cooled reflector and digital ballast over a Gavita Pro E-series. These new fixtures may still carry a premium price, but compared to buying a separate air cooled reflector, digital ballast and HPS bulb, the cost is comparable. The real open question may be is it worth upgrading old style HPS fixtures early (before failure) or wait? There are many factors to consider obviously, but the additional light output and efficiency of these fixtures does translate into increased yields, so for many of our customers the answer has been yes.