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One popular project I want to do with my Arduino is to light up 150 LED Strip of 5 meters (WS2812B).

Here is my project:

enter image description here

So, I have a power supply of 5V 10A (ALITOVE 5V 10A AC to DC Power Supply). 10A because 150 LEDS of 60mA need 9A. But, 9A is a lot and I'm a bit scare to connect everything.

I pretty sure that my jumper wires will not like 9A. Here are my questions:

  1. So why tutorials and guides (see links below) don't care about wires when using 10A with 5V to ligths up strip LEDS?
  2. What kind of cables should I use to connect both the Arduino and the LEDS?
  3. 15 AWG seems big for that, no? I'm not even sure that 15 AWG will fit in the Arduino 5V pin.
  4. Also, I think it may be a good practice to put a capacitor somewhere to protect the Arduino. But where?

Here are the tutorials, guides and people talking about a similar project:

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    \$\begingroup\$ Keep in mind that the traces on the strip itself are nowhere near that heavy, so using heavy wire to connect the strip to the power supply becomes rather a moot point. \$\endgroup\$
    – Dave Tweed
    Commented Oct 4, 2019 at 22:59
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    \$\begingroup\$ @DaveTweed pluggin 9A over 500 mm of 35 µm thick copper with a max temperature rise of 50 K from room temp into Kicad's trace width calculator, I get some 2.3 mm of trace width for a voltage drop of 0.9 V – doesn't sound so unrealistic. Over 5000 mm, however, there will be significant problems with voltage drop, and OP will either need thicker copper than I'm assuming here, or a multi-drop supply. (even counting that the longer we go into the LED strip, the less current it needs to pass through) \$\endgroup\$
    – Marcus Müller
    Commented Oct 4, 2019 at 23:07
  • \$\begingroup\$ You may well notice that the brightness of the LEDs drops the further away from the power feed point. For this reason it is often recommended that you don't feed the power just at one end, If you do it in the middle, for example, the maximum length of copper track to the furthest LED is halved as is the current in each direction, so a 4 fold gain. \$\endgroup\$
    – Peter Jennings
    Commented Feb 17, 2023 at 11:13

2 Answers 2

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10 A because 150 LEDS of 60 mA need 9 A.

Correct.

I pretty sure that my jumper wires will not like 9A.

Correct.

  1. So why tutorials and guides (see links below) don't care about wires when using 10 A with 5 V to ligths up strip LEDs?

You'd need to ask them.

  1. What kind of cables should I use to connect both the Arduino and the LEDs?

First of all remember that you probably can't run 9 A through the LED strips so you won't be daisy-chaining all the strips. Instead, you will need to look at the datasheet for the strips and work out how many strips you can have in series before exceeding the current rating of the flexible conductors. From that you can figure out how many parallel sets of series connected strips you need. Then you can connect each of those sets directly back to the power supply with a lighter gauge wire.

  1. 15 AWG seems big for that, no? I'm not even sure that 15 AWG will fit in the Arduino 5 V pin.

I'm from metric land so I'm not familiar with AWG sizes. In any case, you won't be powering the LEDs from the Arduino, so the wires between the power supply and it only need to handle the power required by the Arduino - probably 50 to 100 mA depending what else is connected to it.

  1. Also, I think it may be a good practice to put a capacitor somewhere to protect the Arduino.

It's not really going to help. There are some on board already but if the lights cause the 5 V voltage to drop a small capacitor isn't going to help.

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  • \$\begingroup\$ About point 2: The spec sheet of WS2812B don't talk about maximum current. But people are saying to put power every 5 meters for longer strip because of the voltage drop. So, I'm guessing that it can handle that Amperage, see: auschristmaslighting.com/threads/ws2812b-max-amperage.10769 \$\endgroup\$
    – probitaille
    Commented Oct 7, 2019 at 14:23
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    \$\begingroup\$ Check after they've been running for some time - 10 minutes should be enough for things to stabilise - and see if they feel hot. It will be hard to tell due to the LED heat. \$\endgroup\$
    – Transistor
    Commented Oct 7, 2019 at 16:24
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So why tutorials and guides (see links below) don't care about wires when using 10A with 5V to ligths up strip LEDS?

If you want to light 150 LED's it will take a lot of current. Running all this through one cable seems a little excessive, and will cause some heating in the wire and traces.

You'd need at least 20AWG for the recommended current of 10A, to power and ground of the LED's and the power supply.

What kind of cables should I use to connect both the Arduino and the LEDS?

At least 20AWG for the LED's and anything over 30AWG for the Arduino (which is probably drawing less than 50mA). There is almost no current through the digital cable.

Also, I think it may be a good practice to put a capacitor somewhere to protect the Arduino. But where?

Nope, the Arudino has a regulator and capacitors, the regulator will attenuate noise, so no bypass cap needed.

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