I want to put my led strip in my PC and control it with Arduino or ESP. Since led strip has 60 leds it's going to draw ~3.5 amps. I'm asking if anything would happen if I connect led strip to 20 amps molex cable of my PSU? I am already writing my code, and this is the only thing that I'm interested in. Thanks!

  • 1
    \$\begingroup\$ There is no generic LED strip, no generic molex cable and no generic power supply that would allow anyone to make a concise answer. \$\endgroup\$
    – Andy aka
    Mar 29 '20 at 12:09
  • \$\begingroup\$ Sorry, I don't understand what are you saying \$\endgroup\$
    – Kule
    Mar 29 '20 at 12:10
  • \$\begingroup\$ If you mean the 4-pin PC peripheral cable, sometimes referred to as the Molex cable, then you need to match the voltage, and be sure that you don't overload your PC. None of these are typically good for 20A, so you need to do more research, or post more details so we can help. \$\endgroup\$
    – Mattman944
    Mar 29 '20 at 12:18
  • \$\begingroup\$ So, molex cable has 2 GND, 12V and 5V. Led strip works with 5 volts, and so every led draws 60mA so I need ~3.5A for whole led strip. I'm just interested if led strip would blow up or something if I connect 5V 20A to it. Voltage is good but I'm not sure about the current. PSU won't be overloaded. \$\endgroup\$
    – Kule
    Mar 29 '20 at 12:25

Both the power supply and the LED strip are fine with that, as long as

  • you don't draw that from the standby power pin
  • you don't give a signal to the LED strip while it's unpowered (WS2812 are notoriously unhappy with that)
  • you supply the LED strip in multiple places (because the copper is too thin to transport 3.5A all from one end)
  • \$\begingroup\$ Thank you, I won't power it from multiple supplies, I'm just going to power it from molex cable, and standby wire is already hooked up to motherboard and it can only supply 2A. Thank you sir! \$\endgroup\$
    – Kule
    Mar 29 '20 at 14:52

This question has been asked here so many times it is getting boring. A properly designed load will only draw the current from the power source that it needs. The power source, if it has greater current capacity than the load requires, is not going to somehow force the load to take five or six times the current that it needs. Assuming that everything stays at the proper voltage of course.

Think about your cell phone charger that you plug into the AC mains receptacle in your house. That receptacle can likely supply 15A at the mains voltage and yet the charger only needs maybe 0.1A or so. By plugging in your cell phone charger it does not explode due to the 15A capability of the receptacle.

  • \$\begingroup\$ So, led strip won't die or anything? \$\endgroup\$
    – Kule
    Mar 29 '20 at 13:02
  • \$\begingroup\$ @Kule - If you understand what I wrote then you can derive you own answer to your question. If you do not understand then I suggest you do more reading and research till you do before connecting up any circuitry. \$\endgroup\$ Mar 29 '20 at 13:06
  • \$\begingroup\$ So, you're saying led strip will only draw the amount of current it needs? If it's like a so then I'm safe? \$\endgroup\$
    – Kule
    Mar 29 '20 at 13:09
  • \$\begingroup\$ If the combined existing load and additional load does not exceed PSU rating then you should be OK. \$\endgroup\$
    – Transistor
    Mar 29 '20 at 13:32
  • \$\begingroup\$ I know nothing will happen to the PSU but will anything happen to led strip? \$\endgroup\$
    – Kule
    Mar 29 '20 at 13:33

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