August 29, 2019

Channeling my inner Clark Griswald, I connected my first set of pixel lights and turned them on to full in xLights, only to find that while many of my pixels looked great, there was a definite “fade” to a brown-ish/pink-ish color across my strings of new LED pixel lights.

Perhaps you are running into this issue with your pixel Christmas light display – you’ve turned things on for the first time and you can see that some of your pixels just aren’t right, especially in white.

Is there a problem with your pixels? Why are they turning brown or pink?

Christmas light pixels turn brown or pink when they don’t have enough voltage in order to run correctly. While they will still technically work, it’s important to fix these problems for the visual look and also the longevity of your pixels.

What’s Going on – The Voltage Problem…

It’s all about power. The types of pixels that we use in Christmas lighting are run at a low voltage, which means that we don’t have a lot of room for the voltage to lower before we have problems, such as the “pinkish” fade that we can see when we turn a long string on full white.

Think of it like this – you’ve got 2 highways leaving a city. One has 120 lanes, the other has 5. As they head into the suburbs, each highway loses one lane every 10 miles.

No, this isn’t one of those evil math problems about the trains leaving the cities at different times…keep reading…

The highway with 120 lanes will have no problems at all – in 60 miles, it’s only dropped a small percentage of its total lanes.

The 5-lane highway, on the other hand, is in big trouble. It quickly loses a massive percentage of its lanes, leaving a traffic jam!

It’s kind of the same thing with pixels…

As power travels across wires, it begins to lose voltage. For things around our house that run off regular “wall-power”, you can get a good bit of drop and have no problem. 5 volts off of a total of 115-120v wall power (here in the US) is no problem.

But 5v or 12v pixels? Just a volt or 2 gets you into dangerous territory – and low voltage power loses voltage across wires at the same rate as the 120v outlet power.

Now that we see the problem, let’s talk about possible solutions. While it’s a singular problem, there actually are 5 different ways we can resolve it!

Solution 1: Less Brightness

Our core problem here is that there is too much voltage drop by the time we get through all of our pixels for them to function properly. This is caused by a combination of long wire length + total electrical load.

If we lower the brightness of our pixels, we will then lower the electrical load, which also lowers the amount of voltage drop across our wire.

Most people do NOT run their Christmas displays at 100% intensity…in fact, many folks run at 30%-50%!

So, if you are running your pixels at full, consider turning them down. The article that I linked to in the previous sentence explains how to find a good intensity for your display, and how to get the most out of each pixel that you have.

This is by far the quickest and easiest way to resolve the problem if you can get away with it!

Solution 2: Power Injection

While the “standard” and most simple set up for pixels is to apply power through the pixel controller, you CAN add in more power as you go to make much longer strands of pixels possible from one controller output.

Power Injection Tee – these make power injection simple.

Power injection works in a few different ways.

If you are using 1 power supply for both feeds of power, you literally can apply the power + and – to both the start and the end of the pixel run. This will feed power from both ends, essentially doubling the length you can run compared to just feeding power at the front end.

Since you were likely going to plug in another string of pixels for your next prop at the end of the first prop anyways, it’s not much harder to add more power.

The only “gotcha” with power injection is that it’s very important to leave a gap in the “+” wire if you are using 2 different power supplies. Fail to do this, and sparks will fly!

Read my full article on power injection here! Power injection can seem complicated, but it doesn’t have to be. However, there are less complicated ways to fix our problem, such as…

Solution 3: Less Power Drop from Cable

One of the biggest rules in low-voltage power is this: get your power supply as close to the start of your pixels as possible.

This applies in the world of Christmas lighting as a 5v or 12v power supply that is 10′ away will have much less voltage at the beginning of the string than one that is 6″ away!

As a general “rule-of-thumb” you want to be sure that you get your power supply as close as possible to the start of your string of pixels. This will ensure you begin the line of lights with as close to your target voltage as possible!

With most power supplies, you often can tweak the voltage to be higher or lower to compensate for long cable runs. While this isn’t ideal, it can work – BUT be very careful to not overdo it, as you can easily fry your lights if you provide too much voltage!

Solution 4: Separate Outputs on Your Controller

I remember reading a survey recently on one of the holiday lighting Facebook groups about power injection.

Many of the folks that manage large displays chimed in, and it was not too surprising that many of them opted to spread their lights across more controller outputs, rather than use power injection.

The idea behind this is simple: Less power injection = a less complicated set up, which also = a faster setup!

Plus, if a prop goes down, you don’t lose any props that are wired after it. And with the SmartReceivers that are now standard for many pixel controllers, you don’t lose output capacity by ending a string early.

So, for most props, it makes sense to just give the prop it’s own port on your controller.

The only time it doesn’t make sense is for more power-dense props, like a matrix. In that case, using power injection saves you a good bit of cost and complexity because there is so much power needed in a small area.

Solution 5: Higher Voltage

If you look at any pixel vendor, you’ll see that 5v pixels are the cheapest, 12v are a little more expensive, and 24v is the most expensive (but most Christmas light vendors do not sell 24v).

Just like we learned above, the higher the voltage, the farther/more lights you can run before you have to add more power or stop.

So, if you haven’t bought your pixels yet, buy 12v. Just do it. If 24v becomes more common in the future, buy those!

And if you do own 5v pixels, then inject power often. As you expand/repair your display each year, begin switching failing props over to 12v – your sanity will thank you!

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