Month: January 2017

The Best Drivers for Single COB Systems

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.

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3000K vs. 5000K Space Bucket Update: 01-25-17

Time for another update on this log, but first, a quick note: I shut down the forum section on the site since it was causing a lot of problems with bots sniffing around and spam users registering. There wasn’t a whole lot of discussion going on anyway, so it’s easy enough to just do away with it. That being said, I’d still love to chat about any questions you guys might have, see your builds, or just shoot the shit about any other interesting LED stuff. From here on, just hit me up on twitter or Facebook, or use the contact page on the site.

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COB LED Constant Current Driver Selection Tool


  1. Select a COB from the dropdown
  2. Enter the quantity of COBs
  3. Select a drive current.

The spreadsheet will calculate your total forward voltage and highlight all of the Mean Well HLG-C drivers that are compatible with the parameters you entered. All data is pulled from manufacturer product simulator tools. If the total forward voltage (Vf Total) of your system falls within the rated constant current range of a driver (between V_min and V_max), that driver will turn green, indicating it is a match. I welcome any and all feedback on how to improve this tool – if you notice an error, have a suggestion, or would like to see other COBs or drivers, leave a comment.

Please note that even though big drivers may be capable of driving tons of COBs in series at low current, the high voltage generated by wiring the COBs in series may exceed the rating of your COB holders or connectors (a number of common holders are rated for a maximum of 250V – this would equate to a max of about 7x 36V COBs in series per driver). Always check your equipment specs to verify it can handle the total voltage.

UPDATE 04/17/2017: Citizen CLU COBs updated to Version 6 (F1), Quantum Board 288 and 304 models added.

UPDATE 05/30/2017: HLG-480H-C Drivers added.

UPDATE 06/16/2017: 72V Cree CXB3590 added.

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2016-2017 Winter Grow: 01-18-17

What’s goin’ on?

Life is good here. Most of the plants in my little grow tent are doing quite well right now, with the exception of the tomatoes, which have endured some abuse in the past couple weeks. I’m having some difficulty striking a balance between giving the tomatoes enough light, while not frying all the greens on my upper shelf. I’ve been lazy lately, and have been adjusting my dimmer by feel without measuring the output – I took my ammeter down with me the other day and was surprised to see I had turned the current all the way down to 400mA!

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How to Easily Compare COB LEDs

When you’re designing a COB LED system, it can be difficult to compare COBs of different brands or models with one another. If you were to try to do it just by looking at the data sheets for each model, you likely wouldn’t quite end up with the exact numbers you were hoping to get, and would have to base your estimates on graphs, then do a bunch of math. Nobody likes math.

The easiest way to compare COB specs is by using the manufacturer’s simulation tool. Most manufacturers release a spreadsheet that allows you to input certain values and then spits out a number of different specifications. If you have an idea of the color temperature, voltage, or current you’d like to run at, you can plug these values into the spreadsheet and see how the various specs interact with one another.

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Lumens, PAR, PPF, and PPFD: Measuring COB Grow Light Output

Want to figure out how much light your COBs are giving your plants? Getting an accurate measurement is a little trickier than you might think.

A quick glance at your standard COB data sheet will probably show you one related specification: its luminous flux rating. While luminous flux is a good indicator of how bright a COB is at a certain wattage compared to others, it’s not the ideal way to quantify how much light your plants are getting. There are many different units and methods used for measuring light, like luminous flux, lux, foot-candles, PPF, and PPFD. Let’s have a lil’ gander at each.

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3000K vs. 5000K Space Bucket Update: 01-08-17

The buckets are in business!

This will be super-short tonight as I’m totally wiped from doing flooring all weekend. I’m going to be pathetic tomorrow – just a whiny, sore, miserable, slug of a human being. I’m almost done though… Just 3/4 of a staircase to go.

Back on topic: I was concerned that my space bucket peppers would never bounce back but it appears they have. Currently, I’m getting mixed results from the 2 different types of peppers, which is probably just due to the fact that I have such a tiny sample size for this little experiment.

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2016-2017 Winter Grow: 01-05-17


I hope you’re all doing well. I’m squeezing in a quick update tonight for the grow tent, but before that, I want to give a shout-out to user Noel for sharing his latest build using Citizen chips. Here’s the final product:

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COB LED Basics: A Beginner’s Guide

After sifting through my posts, I realized that I’ve neglected to write something that’s a little more suitable for somebody who’s brand spankin’ new to the world of LED COBs. This guide will serve as a short introduction to the basic elements of COB LED lighting systems, and is a good place to start if you’re looking to make the switch from other types of lighting, or if you’re new to indoor gardening altogether.

COB LED systems are actually quite simple – there are only a handful of different parts, and they all go together pretty easily. The main components of a COB LED system are:

  • The COB LEDs themselves
  • Heat sinks that the COBs are mounted to
  • LED drivers that power the COBs
  • The wires that interconnect the COBs and drivers.

Not so bad, right? Let’s delve a little further in.

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3000K vs. 5000K Space Bucket Update: 01-02-17

Happy New Year!

I’ve been putting this update off for a long time because things have not gone well and I was sort of disappointed. Nevertheless, here’s where we’re at with the space buckets.

Mexico Midget Tomatoes

As predicted by user noel, the mighty tomatoes could not be contained by the 5 gallon pails, despite expanding them vertically. I’d have to spend a small fortune on 5 gallon pails in order to expand them high enough to make this work – my lesson learned here is that I should have used a tote or plastic garbage can instead of pails for these veggies. I thought that I might be able to top them and find a way to limit their height, but even if I had figured that out, they were also still fairly burnt from getting too close to the light in the first week (and, truth be told, I neglected them too long at the start to notice!).

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