Safely powering up to 600 ws2812b LEDs?

Long story short, convince me to buy 4 of something like these ($65-$100), or 1 of something like this ($18-$25).

I’m making some unnecessarily complicated under cabinet lighting using strips of ws2812b LEDs and a Photon. I currently have 300 LEDs on a 5m strip, but in testing they’re not as bright as I’d like so I may double it up. 300 at full brightness will consume roughly 18A, while 600 would consume 36A. That’s a lot.

With the two options above, the main concern is cost and safety. I’m relatively certain the power bricks wont burn my house down, but they’re pricey. With the other option I’d need an enclosure (metal?) and I’m assuming it’d overheat without active ventilation which I’d rather not have (loud fan plus holes in the case are not ideal in the kitchen).

So what do you think? Is there a good option for powering these things without spending a ton on power bricks?

Edit: Side note, if it matters. I dont think these will be turned on most of the time, except possibly a smaller section at full brightness. Wild guess, I’d say 5A for the “always on” part. Even that will probably auto-dim once I do Photon magic.

Hi Zor,

I’ve never built projects like this, but I’ve read a bit about massive amounts of neopixels.
Adafruit has a pretty good overview of things to consider here:

Things like star topology, how thick the wire should be, how to not-burn-down-your-house…

You’re right to be worried, to quote the adafruit guide:

“With Great Power Comes Great Responsibility.”

To reiterate the opening message, please be super extra careful around this stuff.
Ever had a component on a breadboard explode? One little capacitor or an LED or something? It throws shrapnel at your face and it hurts…and that’s just a tiny amount of power in one tiny part!
We’re not in Kansas anymore. Dropping a wrench or a screwdriver across the
terminals of a high-current power supply can spot-weld the tool in place. The arc can burn or even blind you.

Personally, I would go for the beefy, single supply. Jury rigging several high-amp things together is asking for trouble. Save yourself the nightmare times and house-burning-down risk, and go for the professional stuff, even if it’s twice the price. (that’s still several million times cheaper than rebuilding your burned out husk of a home…)
To quote the adafruit guide again:

Could I instead use a whole bunch of 5V power bricks working together?
Could I drive framing nails with a whole bunch of upholstery tack hammers working together? It’s a matter of the right tool for the job. Large DC supplies are purpose-built for this kind of load, providing consistent voltage across the system. They’re not that much more expensive.

Besides, where would you plug in all those bricks? It would look terrible!

As for the “not as bright as you’d like”, are we talking about the same neopixels? Mine hurt my eyes when I look directly at them, and can light up the entire room in dim light at night. (only a 24-pixel ring).
If they appear dim to you, you may be suffering voltage-sag along the 5m strip.
For longer stretches, Adafruit themselves recommend to add power-lines at multiple points of the strip, to reduce the voltage drop along the (thin!) traces inside the strip.

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Thanks for the reply! Somehow I’d never seen that article before. I’ve read some of the opposite advice as well - using a couple of power bricks is fine, just connect their grounds and you’re good. But I am leaning towards a single beefy power supply. Even if I order domestically (which sounds like a good idea) it’d be significantly cheaper. Just need to figure out how to mount. Definitely going to add a temp sensor to the Photon, and possibly a relay to shut down everything if necessary?

As far as brightness, I currently do have problems with voltage drop. I’m using an uncut 5m strip of 300 LEDs from http://www.aliexpress.com/item//2036819167.html , but I am planning on cutting it into smaller segments. But even driving a limited number doesnt seem very bright compared to a single flourescent tube that I’ll be replacing. But I’ll play that by ear once I have a decent power supply, and I have some connectors I’m waiting on (not going to try soldering connections if I don’t have to).

Do you really need the fancy neopixels, or do you want white light only? If so, there are better/cheaper strips for that.

That works, but is always considered a bit hacky. Works for a one-of or temporary project, but if you’re permanently integrating into your furniture, you want something solid.
I quote the adafruit guide again:

Speaking personally, I would never plug in an imported no-name thing that I can’t pick up and carry the fire outside

I assume he wants some color at least, otherwise he wouldn’t be replacing his current TL light.
The thing to consider would be: does he really need addressable leds.
If not, a few segments of non-addressable 12Volts RGB strip might suffice.
Going to 12V will definitely make things easier, as you could more easily use ATX power supplies. They usually supply the majority of their Oompf at 12V (for all those overclocked video-cards, etc.)
Also, you reduce your amps by 12/5 = 2,4x
The only thing you would lose is the ability to have color gradients along the cupboard, although you could of course have multiple segments that each have their own transistor controller, maybe something like this: http://www.velleman.co.uk/contents/en-uk/p578_ka01.html

That would require a lot more hardware controllers though, so I can see that it might seem easier to do everything with neopixels and software, where it’s “only” the power distribution that’s problematic.

I 100% do NOT need addressable nights. But that’s half the fun. :slight_smile:

True, just don’t burn down your house :wink:

  • Do not skimp on the fuses, one big main fuse, and individual smaller fuses for the individual segments
  • make sure you have a main shut-off switch that is still reachable if all the other parts are in flames.
  • Test it a couple of times on a test-bench before integrating it in the cabinet. (a clean test-bench, no sawdust, screws or iron filings allowed!)
  • leave no wiring exposed, shrink-tube everything before boxing it up. (At these amperages, spot-welding is an issue)
  • keep away from small children and pets
  • post videos :wink:

I’ll do my best. :smile:

Current thought is one of these guys mounted in some sort of case in a liquor cabinet above the stove. I have an outlet up there, and it’s out of the way enough that it wouldn’t bug me. The outlet isnt on a switch though, but that could be changed. I’d greatly prefer passive cooling, but either way I’d like a temp sensor in there, so adding a 120mm PC fan for when it got too hot would probably be a good idea, and it’d be whisper quiet. Adding a relay that the Photon could use to shut everything down might be nice, but I’d need to use a separate PS for it then, so maybe not. Beyond that, yeah, fuses, good wiring, and maybe doing something better with the Photon beyond a bunch of crap stuck in a breadboard. Just need to find a decent case and a few other fiddly bits, and I’ll be off to the races. Man, this is starting to sound like a project…

If it’s not painfully obvious, this is my first real project. I’m a software guy, and I’ve always wanted to get into IoC stuff. After seeing how cheap and capable the Photon is, the relative cheapness of RGB lights, and a horrible misunderstanding of https://learn.adafruit.com/rgb-led-strips/current-draw (which suggests 6A max if you miss other details) I had my first project idea and dove right in! Hopefully I’ll finish someday. :slight_smile:

Ah, that’s okay, everyone has to start somewhere!
I will add that maybe doing a 36A project is a bit ambitious to start out with, most people start with a 2A wall-wart max :wink:
A tip in that respect: it might be an idea to get comfortable with a smaller segment first.
The nice thing about neopixels is that you can program as if you already have 300 connected, but just hook up the first 10/30/60 (or even just one) with a USB wall-wart.
This will allow you to get comfortable with a small set of hardware first, before you dip your feet in the high-amp side of things, so that you discover you were e.g. missing protection circuitry by only blowing up 10, not 300 :wink:
The way the neopixels pass through their data means that any pixels you “forget” to add physically will just be ignored (the excess data is passed down the chain, into obliviousness without effect).

Good choice on the Mean Well, a respectable manufacturer. Little details like the plastic fins around the screw terminals mean you can’t accidentally drop a nail/screwdriver/soldering iron on them and melt it in place :neutral_face:
Since you’re just starting, be sure to read up more on high-amperage projects.
40Amps at 5V is comparably dangerous to working with mains voltage, treat the project with the same respect as if you’re poking screwdrivers into your home’s fuse box. The same general caution should apply.

In case you hadn’t seen it yet, Adafruit also has a “neopixel überguide” that has a lot of introductory information, including troubleshooting tips and hardware you MUST add to make sure you don’t blow up pixels with initialisation power-spikes

Finally, I found this when double-checking the RAM requirements (you’re good, 300 pixels use a 900byte ~ 1kb pixelbuffer, the Photon has 1MB, so there’s still ~999KB for your own program)


The guy shares his code here:

Very new to the community, I have worked with electronics and electrical for a long time professionally. But I am fairly new to the IoT movement.

I would try to stay clear from 5V as stated above, Power causes an inversely proportional relationship to Current and V, so a 200Watt load will be 5V and 40Amp, but a 12V would be 17Amp, 24V would be 8Amp, 120V would be 1.7Amps. Copper wire has a inverse relationship with resistance, so the thicker the wire, less resistance. So Amps of the load really drive the wire size, smaller wires with high amp can get to hot can cause melting, fires, etc, etc. Google American Wire Gauge size charts. AC vs DC does change based on length of wire.

But in this application amps are amps. So you really need to use 8awg wiring for a 5V, which is huge, and expensive. Going to a 12v system will decrease that a lot and you could get away with 12-14awg wiring, 24V even better. But 120 AC at this wattage is 18awg to the power supply. If you are stuck with the 5V system, you are better off going with individual PSs for each series, or run an individual wire to each series.

The advantage of 5V vs 12V or 24V LEDs is based on the application. 5V systems are more efficient, and you can get a lot more of them in a smaller area, which means they are better for screens and such. But if you look at outdoor screens for like a Billboard or TV, they take massive amounts of wattage, so they have huge power supplies and try to break up the series as much as possible.

Powering LED in series is usually never an issue, unless a strip is getting hot from another source. LEDs will absorb energy and either increase current consumption, or also back flow current when turned off if there is no Diode protection. Most Power supplies already have this backflow. But if your amps are at the limit, and one area gets hotter, you will see dimming in other locations.

Powering with one larger PS is best case if you can go with a 12v, or 24v LED. You can either control the whole thing with a SSR or SPDT Relay, or they have off the shelf IoT relay outlets. http://www.digital-loggers.com/iot.html.

If you want zones, you can get smaller relays for each series, they make -5v, or 12v relay boards, I have seen them up to 16 on one board. In this case a mechanical relay is fine, they have the risk of staying closed on failure(which is not a safety concern really), or you can go with SSR boards. Solid State Relays are faster, last longer, and 99% of time fail Open, but I have one instance. You can set these relays up with WiFi control, but need power supplies or you can use the 12v power. Or you can go with RJ45 jacks.

For color phases like RGB, you would need a single relay for each color. I think there are 4 circuit, so a 4 line relay board would be fine.

For wire prep, I do not like using bare stranded wire in a terminal. I would suggest tinning it with solder, or using a wire ferrule tool like http://smile.amazon.com/Signstek-Adjusting-Ratcheting-Crimping-AWG23-10/dp/B00HPRYIL8/ref=pd_bxgy_60_img_2?ie=UTF8&refRID=1467TGCH8NSRGMDG0X0E I would get the assortment of ferrules at 1st, then buy them based on what you need. They make jacketed speaker wire that is designed to go behind walls, this is the safest to use for DC applications. I would not use these for 120V AC lines though, just DC.

You can either go with a jack for each line, or you can use a terminal block. I like using something like this, you can cut them into 2 or 4 line terminals, be cautious of amps. http://smile.amazon.com/X3-0512-Position-Plastic-Screw-Terminal/dp/B00TX2Z2YU/ref=pd_sim_23_3?ie=UTF8&dpID=41bcH59ordL&dpSrc=sims&preST=AC_UL160_SR160%2C160&refRID=1Y2EM1Y5MYV2Y0809EEK
I prefer the solid backing LEDs over the flexible strips.

Sorry if that is too much info, or does not make much sense.

Hi Zor,

few comments from my side.
I"m currently working on a little bit similar project, with 512 neopixels and a Photon.
One simple advise - don’t run them at full brightness, at least not at full brightness white.
Only full brightness white will consume the amperes you are afraid of.
Reducing brightness by half (like from 255 to 128) will greatly reduce the current, and they will be only slightly darker,
since human eye doesn’t work in linear way ! Actually, to see half of the brightness, you should set the brightness to about…36.
And, full brightness would make your neopixels hot. I mean, really, really hot.
So, use the power supply capable of supplying the current for the full brightness, even with a safe power reserve,
but don’t use the full brightness. You will still be happy, and everything will be safer.

As far as 36A being a lot to start with, that’s a bit why I was leaning towards individual power bricks. I can start small(ish) and add more segments as necessary. But yeah, that’s much more expensive, and as the project grows and more LEDs are added hiding a bunch of power bricks is trickier (and it’s janky). I’m trying to plan for what I’m thinking the end state will be, but maybe a couple 10A bricks as an intermediate step isn’t horrible…

Anywho, thanks for your help everyone. I have a lot of design decisions to make. :slight_smile:

I have worked with led strips in large installations and have had serious issues with voltage drop.
Cheap strips have very thin and uneven copper conductors causing the voltage drop and localised heating.
Even quality strips suffer to a lesser degree, a solution is to run a 14 / 16 awg wire and connect it at 2 metre intervals. Similar to a star but less wire.
I made some Christmas tree lights with 60 neopixels (pcb mounted), they became progressively dimmer down the line, solution was to wire them in a ring. The pcbs can run at between 4 and 7 volts.

have a question im making a bunch of nanoleaf panels 29 to be spesific i will be using a 15m strip 900 leds in tottal 35leds each pannel give or take for power suply im will be using a 30A 5v / 150 watts of power i wish to know when power the pannels should i power the strip from start mid and end or just at the start .

You may need a 60A supply to allow for all 900 LEDs to be full white.
You also don’t want to have more than 1.5m between feeding points on a continuous strip - as this would still mean 2.7A across the power rails when all LEDs of that section are full white.

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