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Topic: Powering 5m WS2812B (5v, ~15a) (Read 10220 times) previous topic - next topic

MarcBr

Hello, hoping this is the correct forum.... sorry if it isn't :)
And sorry for the wall of text :(

I need to power 5 meters of WS2812B LED strip (That I will split into 2x150cm and 1x200cm).
It is a 5 volt strip that is rated at 14.4w/meter according to sellers. According to the internet it draws ~50mA per LED at full brightness and there are 300 LED's, so lets say 15A at 5v.

From lots of googling I've figured out that I need to apply power every 1-2 meters or suffer an unacceptable voltage drop. With my split I figure I can feed it from the middle of each strip and it should be okay. I'll feed each strip with 2.5mm^2 speaker cable.

My problem is powering the thing. I've spent more than a day on eBay and Aliexpress trying to find a 5v 15a "laptop charger" style adapter. There are plenty of 5v 20A, 30A, 40A, 60A (!!) switching power supplies but they all have holes or electrical terminals exposed - they're made for being embedded into a larger device that the consumer cannot access. There are also a few "rainproof" where the rainproofing consists of a metal box that you hang it in, and its open at the bottom with the terminals exposed... that would probably be highly illegal here. My usage is residential and I don't want to electrolute any kids or cats.

The closest I've found are:
5v 8A: http://www.ebay.com/itm/350794968653
5v 10A: http://www.ebay.com/itm/121177458319

So, one option is to get 2 of the 8A's, plug them into the Arduino project box using 5.5x2.1mm DC plugs (if I can find any rated for 8A), power the Arduino and 2 of the strips from one rail, and the other 2 strips from the second one. Connect the ground between both supplies and the Arduino and the LED strips in a star pattern (I guess?).

I'm not so sure I like this idea because the DC end of the power cable from both those adapters seem VERY thin for 8A of current. Maybe I'm imagining things?

Another option I came up with is.. I have a  24v 5A power supply (that I was going to use for a 24v RGBW strip before I discovered WS2812B's).  What if I take the output from that one and plug it into one of these 12-35v DC to DC converters with 15A output at 5v? Or one of these, or even two of similiar ones with lower rating?

Third option - Use a whole bunch (5? 6?) of 5v 2-3A "chargers". I don't like this idea AT ALL due to it being plain ugly.
Fourth option - ATX power supply... Don't have any spare ones, and they're big and noisy and do way more than I need.

Its going to be used for a clone of Philips Ambilight using boblight on a 65" tv, so I really do need almost 5 meters, and neatness when it comes to cabling is a huge plus.

Any opinions would be appreciated... I'm hoping I'm not the first one with this problem :)
I can't really decide between option #1 and #2...

Grumpy_Mike

You don't have to use just one supply, you can split it up over two or more. Just make sure all the grouds are together and you don't connect the +5v lines. This is easy because you have to supply power to each short length anyway.

MarcBr

Yeah, that was my first thought, but I'm kind of running out of room in my media bench for a bunch of power adapters so I'd rather try to avoid it..

How about that DC-to-DC converter? Would a 24v 5a supply and two of the 24v->5v 10A converters be a good idea?
Or a terrible one? :)

Grumpy_Mike

Quote
but I'm kind of running out of room in my media bench for a bunch of power adapters so I'd rather try to avoid it..

Well three low current power supplies are going to be much smaller than one high current one.

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How about that DC-to-DC converter

An expensive and a terrible idea.

MarcBr

Okay, thanks. :)
I guess I'll go with 2x8A then, or 4x5A, whichever is cheapest.

Out of curiosity, what makes the DC-to-DC option terrible? Efficiency? Heat? Something else?

Grumpy_Mike


Paul__B

In terms of efficiency, just go get the proper 5V 20A supply, bolt it down wherever it is not conspicuous, and construct a shield or get a generously sized enclosure (with ventilation) to cover the terminals.  If it is a fixed installation, definitely the latter.

Amongst other things, that is going to be the most reliable.   More so than bricks.  Ventilation is critical.

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