I have got an electronic speed controller as pictured in the first image. What kind of contacts are those on the left? The second image is a closeup.

edit to clarify question

I am asking how to physically connect these contacts.

Are these pins or plugs? Are they for soldering? If yes what is the advantage over just soldering two wires together.

  • $\begingroup$ Made an update. Question is just how these connectors are physically used. $\endgroup$
    – tauran
    Feb 8, 2019 at 18:09
  • 1
    $\begingroup$ now your question makes sense ..... that is a solder cup ..... do a google image search if you like .... slip the heatshrink tubing on to the wires as far away from the connector as possible, solder the wires, wait for connector to cool, slide the heatshrink tubing over the connection, use a cigarette lighter to shrink the tubing $\endgroup$
    – jsotola
    Feb 8, 2019 at 21:56
  • $\begingroup$ Thanks. Can you explain the advantage for this use-case? $\endgroup$
    – tauran
    Feb 9, 2019 at 13:03

2 Answers 2


In your second image, they look very much like the connectors used on the standard XT-60 connector which are design to be soldered onto. XT-60 connector

edit: To clarify, I'm not saying to use an XT-60, just that they are a similar design. For help with soldering these have a look at http://www.mindsensors.com/blog/how-to/tutorial-soldering-xt60-connectors

  • $\begingroup$ You are right. That could mean those are parts that simply help with soldering two wires together. $\endgroup$
    – tauran
    Feb 8, 2019 at 19:08
  • $\begingroup$ @tauran, feel free to upvote :) $\endgroup$ Feb 8, 2019 at 19:10

The one shown in the second image is a type of a bullet connector. If you consider the whole ESC, the black 3 wires goes to brushless motor. Red and black wires on the other side goes to the battery.

The advantage of using bullet connectors is you can unplug the ESC from a motor anytime. This has several uses like,

  • Test several motors with one ESC.
  • Change a damaged motor from the system without taking the ESC out.
  • Reverse the motor when needed.

There is nothing wrong with soldering wires directly if you don't have above concerns.


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