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On my Reprap-like 3D printer, I routed all the wires to a spot near the base; for the motors, endstops, thermistors, etc, I plugged them all into a DB25 breakout board, and that's working great.

For my Extruder (12v), and my heat bed (16v), I'm using a 4-pin molex connector -- like we used to use for old hard drives and such, and it's working, but it gets a bit hot, and my print bed is having trouble reaching temperatures that it didn't have trouble with before. -- None of the wiring gets hot at any other point, and none of the other connectors get hot. -- The only thing that gets hot is this one molex connector.

I believe the heat is caused by passing too much current through that molex connector. -- I'm curious to know what other connectors might be better suited to this task. Can you recommend something that's worked well for you, or others?

I prefer not to double or triple up this connector if it can be avoided, so that I can just have one physical connector to disconnect there, and so that I don't end up mixing them up. -- also, being able to easily disconnect it is important (it's hard to work on the reprap if I can't spin it around or turn it over, etc., that's why I'm using connectors for everything).

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You might be able to use one of the connectors (Deans Ultra, EC3, XT-60/30, Bullet) that are normally used for RC models. They're made for very high currents. The XT60 connectors depicted below are rated for 60A continuous (well above what you'd need for any heated bed); their smaller XT30 cousins are good for 30A but less commonly available.

XT60 Connector (Photo by Mark Fickett)

For your extruder you wouldn't need anything quite as drastic as an XT60, even a simple JST connector would suffice (though if you are going to source XT60/30's for your heated bed anyway, you might use them here as well).

JST Connector (Wikimedia Commons, Mike Mahoney)

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  • $\begingroup$ Thanks @Tom, I'm looking at these on Amazon right now, and I'm trying to figure out, are these solderable, or do they crimp, or what? -- What's the preferred way to attach wires to these connectors? Do I need a special crimping tool, or can I just solder them? $\endgroup$ – BrainSlugs83 Oct 8 '16 at 1:46
  • $\begingroup$ These are meant to be soldered. They have a semicircular tube on the end, which you fill up with solder. You should also pretin the wires. You then melt the solder that is in the tube, and insert the wire. See e.g. this $\endgroup$ – Tom van der Zanden Oct 8 '16 at 8:30
  • $\begingroup$ +1 RC battery connectors are a great option. Easy to source, cheap, and easily handle the current. Another option is Anderson Powerpoles. They crimp instead of solder, they can be made into multiple wire bundles, and they have a single style connector that fits together (no male/female). Like these: link I like and use both. $\endgroup$ – Chris Thompson Oct 9 '16 at 18:51
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I agree with Tom's answer about RC connectors. Another good connector option worth considering is Anderson Powerpoles.

  • They're "modular" so you can use them to assemble connectors with multiple wires.
  • They crimp instead of solder (I really recommend the special crimping tool if you plan to use these regularly)
  • They're more expensive
  • No male/female, you use the same connector on both ends so you never run out of either male or female ends.
  • The small size is a little larger than an XT60 connector.

Anderson Powerpole connectors next to XT60

Both good options depending on your specific needs.

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  • $\begingroup$ Neat. -- I may look into these for a future project, or if the XT30 connectors end up not working out. -- How much current can they handle? $\endgroup$ – BrainSlugs83 Oct 10 '16 at 0:07
  • $\begingroup$ The size shown here works with 15, 30, or 45 amp spades. The special metal spades get crimped onto the proper gauge wire, then they snap into the plastic housing. They also have larger sizes and all sorts of accessories like panel mounts, etc. More here. $\endgroup$ – Chris Thompson Oct 10 '16 at 21:08
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I've had great luck with "G16 aviation connectors" -- easy to find with a Web search, and they come in any number of pins from 2-10 (the 10s are a little harder to find). Round (so easy to panel-mount), metal barrels, locking ring so they don't come loose. If you get ones with a couple extra pins, you can double up on pins without having to double up on actual connectors. I used a 4-pin for the hot bed (2 power, 2 thermistor); 10-pin for the extruders (4 motor, 2 heater, 2 thermistor, 2 fan), and 8-pin for each axis (4 motor, 4 limit).

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