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I have a problem with my breadboard jumpers. They overheat when I try to power many LEDs, but we're "only" talking 5.05V at 2.1A.

The wires are really thin and they melt after 10-15 minutes of constant use. Even the breadboard melts where the wires are installed. I know it's not ideal to use thin breadboard wires for this, but since I'm powering this together with an ESP8266, I need to use relatively thin wires.

The wires going to the LED strip are about the same size as the breadboard wires.

What alternative do I have to this? I tried installing a fan inside my cylinder (LEDs wrapped around the cylinder), but it's not powerful enough to cool them down.

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  • \$\begingroup\$ Maybe not a long term solution, but you could parallel multiple jumper wires in the meantime to see if that helps. \$\endgroup\$
    – Jim
    Aug 22, 2017 at 13:19
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    \$\begingroup\$ Using a breadboard at 2A is just asking for trouble. \$\endgroup\$
    – brhans
    Aug 22, 2017 at 13:19
  • \$\begingroup\$ You cannot beat Joule's law and thermodynamics! You either need wires with less resistance and/or a better cooling system, which might be exceptionally pricey if you insist on using those fuse-like wires! \$\endgroup\$ Aug 22, 2017 at 13:20
  • \$\begingroup\$ @brhans At ~10 watt though? \$\endgroup\$ Aug 22, 2017 at 13:20
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    \$\begingroup\$ Not only the resistance of the wires will be bugging you but also the contact resistance is quite high on a breadboard. The "contact" is just some wire (covered in dirt and oxide) clamped by a small metal thing. That's not suitable for high currents. \$\endgroup\$ Aug 22, 2017 at 13:24

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Breadboards are not suitable for those kinds of currents. As a rule of thumb, I would avoid putting more than 100mA through them.

Regarding your wires, you simply need to use thicker ones. They often have a current rating, do not exceed it and you should be fine.

As Bimpelrekkie said in comments:

Not only the resistance of the wires will be bugging you but also the contact resistance is quite high on a breadboard. The "contact" is just some wire (covered in dirt and oxide) clamped by a small metal thing. That's not suitable for high currents.

To solve that, simply solder your wires, do not go through the breadboard.

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  • \$\begingroup\$ The small wires from an USB cable can easily handle 2 amps. They do get hot, yes, but they don't start melting. What's the difference there? \$\endgroup\$ Aug 22, 2017 at 13:23
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    \$\begingroup\$ Wire gauge is not the only parameter, different materials have different resistance, and if i remember correctly, breadboard wire is not very good. If your drive your leds using PWM, you could also have skin effect losses \$\endgroup\$
    – Sclrx
    Aug 22, 2017 at 13:27
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    \$\begingroup\$ The small wires from an USB cable can easily handle 2 amps Define "easily handle" OK, they do not melt but energy is lost nonetheless. If I want to charge something with 2 A over USB I do need to use a USB cable with thicker conductors or the voltage drop will cause the current to be less than 0.5 A. \$\endgroup\$ Aug 22, 2017 at 13:28
  • \$\begingroup\$ @MortenMoulder, it is good practice to wait at least 24 hours to accept an answer, to give us the time to produce good quality answers. \$\endgroup\$
    – Sclrx
    Aug 22, 2017 at 13:33
  • \$\begingroup\$ @Sclrx When I know that's the way to go and that's the answer, I'm more than happy to accept it as an answer. People coming with new answers can only extend the answer already written, so that's a no-no in my book. \$\endgroup\$ Aug 22, 2017 at 14:11
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You need to separate the logic part of your circuit from the high power part. Even if you power the (regulator for the) ESP8266 from the same ultimate source, it needs its own runs to that. Whatever you do, don't try to power a high current load from the same tiny wires feeding the ESP8266.

In a temporary breadboard setting you probably want some sort of hefty terminal strip to power the LEDs, with some smaller wires coming off that providing power to the ESP8266 only and then a wire bringing the command data from the ESP8266 to the LEDs.

If your LEDs do not directly take a data command and instead need to be dimmed by MOSFETs, you should probably put them on a dedicated PCB, though you have the added complication of bringing the gate signal from the ESP8266 over to it without creating an ESD exposure risk which could damage the MOSFETs.

It sounds like you are trying to actually deploy a breadboarded system in an enclosure. This is just a not a sound idea - outside of something like a museum installation under glass where the "you could make this" aspect is on display, you really need soldered / crimped / terminal strip connections in a deployed system, either on custom PCBs or carefully wired point to point ones.

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  • \$\begingroup\$ I have soldered the entire thing on a PCB and discarded the breadboard and jumper wires. After 10 minutes of constant white at the 2A, the wires aren't even warm to the touch. I simply needed to hear if there was a better method, but it seems like this is the way to go. \$\endgroup\$ Aug 22, 2017 at 14:45
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If you want to have the same amount of current going through the same wire with a different outcome, the only option I can think of is to triple up your wires -- though if they're already melting that might not be enough.

I have no idea what you mean by "powering this together with an ESP8266", or why that means you can ONLY use thin wires. You should certainly use lower gauge wires for current-carrying lines. I doubt that your WIFI module needs a ton of current.

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  • \$\begingroup\$ I might need to reword that, yes. This is all powered through USB and it works great, actually. I am limited by the power supply at the moment, but I don't want to exceed 2A. It sounds silly to me, that I run thick wires internally but the wires coming from the actual USB cable, which carries all the current, are thinner than the breadboard jumpers. They do not get hot, however. \$\endgroup\$ Aug 22, 2017 at 13:25
  • \$\begingroup\$ @MortenMoulder It would surprise me if you're getting 2.1A out of a USB, especially if its USB2. Your motherboard would not like doing this. \$\endgroup\$ Aug 22, 2017 at 13:37
  • \$\begingroup\$ Oh it's 2.1 ampere. I'm using a wall charger for my Samsung Galaxy S7 Edge, and I've measured 2.05-2.1A with my multimeter. \$\endgroup\$ Aug 22, 2017 at 14:14
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    \$\begingroup\$ @MortenMoulder -- that's different from "USB" -- this is from a charger. You really should take a step back and give us a complete picture, rather than having us drag it out of you piece by piece. I still have zero idea about why you're limited to thin wires, and you're not helping me to figure it out. \$\endgroup\$ Aug 22, 2017 at 15:15
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    \$\begingroup\$ @MortenMoulder -- probably "USB Charger", or "wall wart with a USB cable". You "supplied" 2.1 amps with the charger -- you "measured" it with a multimeter. People do, in fact, read what you write down, and if your language lacks precision, so will our understanding. Many won't read comment threads on individual answers, and comments are not guaranteed to never disappear, so important details like your power supply probably belong in the original question. \$\endgroup\$ Aug 22, 2017 at 16:42

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