Since a lot of people have been looking for help on their strip builds, I figured it’d probably be helpful to have a calculator just for this. Now that we’re seeing more and more of these systems being built, it has become apparent that running all strips in parallel is the way to go – it’s expandable, the math is easier for large numbers of strips, and wiring is less confusing, so I’m only doing this for parallel builds. Check out the parallel strip build tool below!
From Instagram live: Taking another run at overpowering a QB288, this time with an HLG-600H-54 and a boost converter. Sorry for the crappy quality and vertical video – the format it saves to isn’t great for watching on PC.
I’ve had a number of requests to put up a constant voltage version of my COB LED Driver Selection Tool so I drafted one up today. Please see the notes at the bottom of this post for some important additional info. Also, if you’d like to see any COBs added, let me know which ones and I’ll see if I can include them.
Constant voltage drivers are becoming more popular lately. They’re safer, flexible, and often cheaper than their constant current counterparts, but it can be a little more difficult to pick the right CV driver for your system than it would be for a CC build. Don’t sweat though, it’s really not very hard. All you need is an understanding of how parallel wiring works and to know how to manipulate forward voltage and current numbers using data sheets or product simulators.
Below are the steps to take to find a suitable constant voltage driver. Continue reading
In my previous test, I ran a couple of Vero 18 COBs at their typical rated current to see if I could get either of them to go into thermal runaway. Over the 4 hours I tested them, each of the COBs ended up pulling an additional ~50mA each than what they started at, but stabilized at this level. Curious to see if I could get one of my COBs to go thermal, I decided to take another stab at this and hit a couple different chips with considerably higher currents than they’d normally be run at.
Here are my results:
After playing with my new HLG-100H-36A constant voltage driver for awhile, I conducted a little experiment this weekend to see if I could get either of my Vero 18 COBs to go into thermal runaway. Thermal runaway can happen in constant voltage systems where the current is allowed to vary, while the voltage is held steady. As the COB LEDs heat up, their properties change, and this causes them to draw more current, thereby heating them up further and drawing even more current. Eventually, the LED can destroy itself due to this cycle of drawing more current and heating.
Quite often, you’ll see recommendations to add a resistor in series with your LED if you’re using a constant voltage driver. I wanted to see if I could get away with skipping these resistors and simply running my COBs hooked up directly to the driver.
When it comes to wiring LED COB circuits, series configurations with constant current drivers are generally the easiest way to go – especially if you’re new to electronics. Since LEDs are semi-conductors and operate a little differently than most basic circuits, it’s far easier to simply drive them at their rated current with a constant current driver than it is to try and produce that current by providing a constant voltage. If you check the datasheet and find that your LED COB has a typical forward voltage of 36V at 2400mA, you don’t want to strive to give the LED 36 volts, you want to strive to give it 2400mA at whatever voltage that current happens to occur at.