Orchid Borealis

I covered how to convert shop light fixtures to use efficient T8-LED in a previous post .  The efficiency of T8-LED bulbs are widely variable, and the efficiency of commonly available T8-LED bulbs has been slowly improving.  However, the bulbs from Lowes, Home Depot, or Walmart are way behind, and they are still at least 20% less efficient than Sunritek bulbs which are 2 years old.  Now there are T8-LED bulbs with the efficiency higher than Sunritek.  But you do need to source these directly from China, and you probably won't be able to get those locally for a couple more years. I haven't had any failure with Sunritek bulbs (>50 bulbs), and I have been extremely happy with the results.  I have converted all of the shop lights and I needed additional fixtures to use Sunritek T8 LED bulbs.  I decided to use left-over lumbers to make a fixture cheaply.  I made the frame with 1x4 and L-shaped hardwood trim and painted it.  Mine will be used in ...

This was written in 2016, and since then, there are several linear modules which have higher efficiencies.  At the very end of this post, I added the information about these updates.  Samsung EB-Series Gen. 3 Slim version is probably the one I would use (Sept 2019) if I were to redo this fixture. Happy thanksgiving, everyone! Recently, I needed a grow light for a relatively small grow area (the plastic container shown above).  COB LEDs are great for a large area with enough vertical space.  I could have used smaller COB LEDs, but I thought something like Philips XF-3535L ( previous post ) would be great.  After comparing quite a few LED linear modules, I determined that Samsung H series has the best performance for the price at this moment.  Indeed the efficacy is amazing, even higher than typical COB.  But it does cost a bit more per light output than COB.  So here is a brief report of this build. Samsung H series was announced in summer...

4'x4'x8'x grow tent with 8 COB LEDs installed. In this post, I'll try to explain the basics of how to match LEDs and drivers.   I use chip-on-board (COB) LEDs as examples, but the principle applies to any LEDs.  Here are links to my previous blog posts about DIY COB LEDs and linear LED modules .   I'll cover the following topics: Basics Matching the LEDs with the driver Multiple LEDs driven by a single driver An example of my setup with 4x CXB3590 Measurement of light coverage homogeneity 1. Basics Types of drivers: Most LEDs require direct current (DC), so alternating current (AC) of the power outlet has to be converted to DC.  This is one of the roles of LED drivers (power supplies).  We usually use something called constant current (CC) drivers instead of more common constant voltage (CV) drivers.  A CV driver is similar to a computer power supply, USB charger/outlet, or some of "wall bricks" used for some appliances.  An USB outl...

 CXA3070 + TE holder Introduction and COB advantage: I have posted about other LED lighting options for plant growing.  The high-efficiency T8-LEDs from Sunritek are fairly impressive.   Philips XF-3535L involves a bit more work, but it is very easy to assemble.  Here I'm showing how I assemble a Chip-on-board (COB) based project.  It is the workhorse and the performance leader of DIY-LED world at this moment. From my point of view, the 3 advantages of COB LEDs are the easy assembly, high efficiency, and affordable cost.  You can make a highly efficient fixture with the individual LEDs, but generally it ends up costing much more than COB based units. I think the majority of DIY LED people have migrated to use COB technology now.  Some of the grow light makers are finally catching up and started to use this technology.  If you prefer a pre-made COB grow lights (but you need to pay at least 2x of the DIY cost), following companies offer COB...