Looking for the best way to attach your COBs to your heat sink? Use a COB holder.
COB holders make it much easier to fix your chip to your heat sink and, more importantly, they make wiring far simpler as well. Rather than soldering (which sucks), COB holders offer “poke in” connectivity instead: just strip your cable and push it into the designated holes in the holder. There aren’t many manufacturers of COB holders – the 2 brands that are most prominent are Ideal and BJB. Some COBs (like Bridgelux Veros) don’t require holders at all.
The latest tech to get the LED growing community all riled up has been dubbed “Quantum Boards” by the fine folk who designed them over at the Horticulture Lighting Group. These things have created quite a buzz across the usual forums that growers frequent, and for good reason. If you haven’t heard of them yet, you’re likely wondering what exactly a Quantum Board is and what’s so great about them.
Tonight I wanted to see just how close most of the popular COBs are in terms of lumen output at various wattages, so I punched some numbers into the manufacturer product selection tools and compiled a list. All results are calculated at a case temperature of 55 degrees Celcius (except for the Luminus CXM-22, for which I estimated Tj to be 85 degrees in order to have a case temperature as close to 55 C as possible). A color temperature of 3500K and 80CRI was used for every COB.
There’s a ton of information out there about finding drivers for your 4+ COB systems, but not a whole lot regarding drivers for setups with only 1 COB. The main problem is that most of the popular drivers for bigger systems have constant current ranges that are too high for a single COB, so they won’t work. We’ll need to find smaller drivers with similar characteristics in order to properly power your single COB grow light.
This post will examine a few different constant current drivers that will work for single COBs of different voltages. Note that these models are chosen with 120V AC power in mind, and may not work if your mains are 230V or whatever else. Always check the input voltage rating in the data sheet to be sure.
Tonight, I want to share a bizarre-looking heat sink I found that’s made specifically for the kind of COBs indoor LED gardeners love to use, like the Cree CXB3590 and CXB3070, as well as the Bridgelux Vero 29 and Vero 18 series.
Northern Grow Lights’ SST X Passive Heatsink (shown above) looks alien in comparison to a standard “finned” heat sink, but has some very interesting advantages over the classic design, according to their product page:
Pin heatsinks have a unique pin geometry that uses surrounding air streams for a very effective cooling. The round, aerodynamic pin design reduces resistance to surrounding airstreams that enter the pin array, while simultaneously increasing air turbulence. The omnidirectional pin configuration allows air to enter and exit the heat sink in any direction and exposes the heat sink to the fastest possible air speed. The superior airflow and the high emissivity of the anodized heatsink surface allows Pin heatsink to offer an exceptional cooling for your COB LED. Compared to other undersized Pin Heatsinks, our large pin heatsinks are rated to provide better cooling and ensure reliable LED operation and minimum Light Loss over time.
A heat sink with this small of a footprint that is rated for passive cooling (no powered fans) of a 100 watt LED is really quite impressive! I intend to get my hands on one of these to do some testing in a new build.