# Chaining up 5v LED strips using 5v cellphone chargers [duplicate]

I want to chain up a very long LED strip to a single source of data. I will be using an ESP8266 and about 15 meters of WS2812b LEDs. With about 30 LEDs per meter, I need to power about 450 of these total. I've read multiple places they're about 60 mAh each, so 60 * 450 = 27A required to run all of these, assuming I want full brightness at red or white (not sure which draws most).

I've experienced that I can (but should not) power about 6 meters (180 LEDs) with a single 2.1A supply, which actually ended up drawing 2.3A (Samsung phone charger). I wrapped the 6 meters around a tube, so I could easily solder some wires from the top to the bottom, so the voltage drop was lower. Every color looked great, but white had a yellow look to them. I know that wasn't suitable at all, but I was simply trying it out.

I'm now trying a different approach, which should work much better. If I for every 3 or 4 meters wire up a wall charger to the strip, can I achieve what I want? This is what I had in mind:

Here's another thing I had in mind, which would help a lot, since I don't have wall outlets every x meters in my house. Can I do something like this instead, if I make sure to use good gauge wires, so they don't lose voltage?:

As a third option, I have a couple of 12v 2A supplies (like the ones above). Can I buy some cheap, alternative hardware, such as voltage regulators, and wire it up in an alternative way?

The question here is not powering the strips. The question is really if chaining the supplies as my first image is possible and what might could go wrong, if I do it that way.

• your second option will require VERY thick wire. Have you considered using a higher voltage (like 12 or 24V) and have DC/DC converter feeding your strip on regular interval? – MAB Nov 17 '17 at 20:24
• @Trevor If only that was an actual duplicate. Surely our end result is the same, but we're definitely not asking the same question. – MortenMoulder Nov 17 '17 at 21:26
• @MAB Yes, but I only have a couple of 12v supplies. Buying voltage regulators is an option, but I'd rather not buy new supplies. – MortenMoulder Nov 17 '17 at 21:27
• yes I just added the link because it is the same issue, you just have a rather different and novel idea of how to fix it. – Trevor_G Nov 17 '17 at 21:28
• by the way, I was measuring the current used by one 1m|60led strip I have, full white (255,255,255) and I only get about 35mA@5V per LED. Check yours, you might not need as much current as you think. Some safety margin is good, too much is just wasteful. – MAB Nov 17 '17 at 23:59

If you use 5V 2A power supplies then you will need 15 of them. The positive wires of each (30 LED) strip should be isolated from each other so that each supply is only powering one strip. It will work, but the mains wiring required is bulky and awkward.

Your second idea is not good because the power supplies won't share the load equally (some will put out slightly more voltage than others, causing them to deliver more current). It would be better to use a single power supply rated for at least 27A. Strips which are further from the supply should have thicker wires to minimize voltage drop. The downside of this option is that you need a lot of relatively thick wires.

Using higher voltage and dropping it down at each strip with switching regulators would allow you to use thinner wires. Several strips could share the same power wires because the regulators will compensate for voltage drop along the line.

However 5V * 27A = 135W, so two 12V 2A power supplies (48W) will not be enough. 135W / 12V = 11.25A. If the regulators were 85% efficient then you would need at least 11.25 / 0.85 = 13A at 12V. Again it would be better to have a single power supply that can handle the total load, rather than trying to parallel several smaller supplies.

• I appreciate your reply! I could use a single 27A rated power supply, but I would still have to wire long wires to it, right? I doubt the current and voltage can reach all the way to the 15th meter, if I hook it up in the beginning (or even 7.5 meters if I hook it up in the middle). A good thing about this is, I don't need anywhere near the 60 mAh for each LED. Not even close. I can power at least 60 of them (2 meters) without noticing any color change with a 2.1A 5v charger. In theory they should draw 3.6A (60*60/1000) but there's literally no difference between 30 or 60 LEDs. What would u do – MortenMoulder Nov 17 '17 at 21:33
• I would measure the current draw of a single strip at maximum (white) brightness, then multiply by the number of strips you want to power (I based the current on your specs, but it may that your LED strips draw less). Choose a power supply or supplies which can supply that current. Powering a long strip in the middle halves voltage drop at the ends, but probably isn't necessary unless the strip is very long. You may not see any brightness variation (unless voltage drops below 3.5V due to excessive wiring resistance or power supply overload) because the WS2812b regulates LED current. – Bruce Abbott Nov 18 '17 at 4:09

If you go on ebay they sell 1 male to multiple female connectors. Having multiple power supplies is not ideal because if one goes out it puts stress on the LED strip and could short out the strip and other power supplies.

With one power supply and wires to divide it evenly if it goes out, the whole thing goes out without the risk of a short in the microchips in the strip. One strip one power supply is best. An adjustable power supply to lets you choose your voltage and amperage and they are cheap. The 50/50 rgb has more versatility then that brand in you picture which looks like a 30/30. The 50/50 come with built in power connectors.

You will have more difficulty tracking down the bad power supply in your example if it goes bad without a multi-meter.

If you hard wiring this without a control box(small control CPU that con be programmed for sequenced patterns and brightness) a 3 12volt dimmer switch for each color would work.

The control box does have a timer and can be thrown off by multiple power supplies.