this post was submitted on 16 Sep 2025
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So far I have been using RCY connectors to connect some low power fans for a custom thingy (fursuit head, this will be relevant later (space limitations)). They have a fairly low power draw, so around 5v 0.1A.

This has worked for around a year, but as there is a lot of movement where I use it, the power leads have ripped right at the connector. It looks like this is caused by the lack of any strain relief as the connector is crimped and does not have the usual stress relief thingies, which are often seen at other stuff like psu cables, usb etc.

So I'm looking to upgrade / replace that with a different connector. I'm looking for one which has:

  • stress relief against bending
  • is twistable / unidirectional (so something more like a barrel jack / headphone jack)
  • is small / slim (I have very limited room that's why I initially used RCY). The size is mostly limited in thickness, not length.
  • is able to carry the very low voltage and current of 5v 0.1-0.2A (so basically anything will do that)
  • available in germany (most likely most things should be)

Things I have already considered:

  • 5.5mm 2.5mm (/2.1mm) barrel type connector --> too thick sadly
  • trying to protect the RCY plug with stuff like shrink tubes --> doesn't work, just slips off
  • thinner barrel type connectors --> can't find a matching set of cable with plug and cable with receptacle

Rn my best bet seems to be 2.5mm headphone jacks. I do have the feeling that there might be something better out there, so that's why I'm asking here.

Any help would be very appreciated. Thanks in advance!

Edit: Thanks for the suggestions so far, I forgot to add it to the list of the requirements that, the plug needs to be round, as one of the issues I had is that the 90° edges of the plug can get caught in the fabric. So I'm really looking for something round, so something without sharp hooks and release mechanisms.

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[–] actionjbone@sh.itjust.works 0 points 8 months ago (1 children)

If you know anybody who 3D prints, that may offer a solution.

I've printed custom wire reinforcements in TPU. They are very flexible, and they will take the strain off the wire itself.

Any crimped or soldered joint is going to be a weak point. So if you can't find something strong enough? Make it!

If you don't know anyone who has one, you could check thingiverse.com and printables.com for a model that meets your needs, and there are plenty of print services who will make them for you.

[–] lennyaa@pawb.social 0 points 8 months ago (1 children)

I do have a 3d printer but, that one is currently sadly unable to print anything else than PLA (it's a craptastic old anet a8) and I don't know anyone at least close by who can do TPU. There is one thing I forgot to add to the original post, one additional reason I want to get something else than RCY is because of the jagged edges. They to tend to get caught in the fabric every know and then. But thanks for the advice so far, I will consider it.

[–] Blue_Morpho@lemmy.world 0 points 8 months ago (2 children)

Have you tried tpu? Googling says it works on the A8.

[–] actionjbone@sh.itjust.works 0 points 8 months ago (1 children)

Yeah, older printers' extruders had some trouble with TPU, but TPU use similar temperature ranges to PLA.

It's worth a shot, at least.

[–] Blue_Morpho@lemmy.world 0 points 8 months ago

The other option is regular Pla. It's flexible when thin. And I think he needs some stiffness to protect the cable from bending too much.

[–] lennyaa@pawb.social 0 points 8 months ago

It barely prints PLA and from what I heard TPU has a bit more friction then PLA (please correct my if I'm wrong). As the frame of my anet a8 is very craptastic, because I basically got it gifted as it was broken and I needed to power glue some parts together as the crappy plastic frame was party broken. So the frame is weak and it's also the bowden tube variant where the bowden tube heavily limits printing speed where even regular PLA printing speeds are very slow. If I up the speed from very slow even a tiny bit, then the motor feeding the bowden tube skips the filament. (Shortening the bowden tube any more isn't possible as it's already as short as possible) Mounting the filament motor directly to the extruder isn't really possible as the frame is so weak that it will literally tear itself apart if any more force is put onto it.

I know that printer is basically at the point of self disassembly and I will replace it soon, but not yet.

(PS And yes I do monitor it when it prints very closely via a webcam in case it does start self disassembling) (PS PS. I did upgrade the firmware to merlin so it does have thermal runaway protection)

[–] vk6flab@lemmy.radio 0 points 8 months ago (1 children)

If you make the wire (much) longer and put the connector in a location where there is less movement will solve both the restricted space and disconnection due to movement.

[–] lennyaa@pawb.social 0 points 8 months ago* (last edited 8 months ago) (1 children)

Thought about that as well, but sadly that's not possible. I do have other locations to place the connector but those are only worse and have even more movement. Rn the connector is placed against some rigid foam where there is the least amount of movement but is somewhat influenced by the powerbank pouch. The only place I can move it, is to make the cable longer and place it at the bottom of the powerbank pouch where there is only soft faux fur which experiences a lot of movement during walking and turning the head.

Smol edit: Just re-read the part about "disconnection due to movement". --> The plug itself does stay connected. The wire at the crimped part ripped due to the stress of bending and the hard corner of the plastic casing of the RCY plug being pressed onto it. The plug itself does not get disconnected due to movement. I have only unplugged the plug in the photo to show the ripped cable better (the black wire of the negative side is ripped there).

[–] vk6flab@lemmy.radio 0 points 8 months ago

If it's not breaking due to movement, but only due to strain, putting the joint at the power bank seems like the logical choice. You can use cable sheathing or heat shrink where the damage currently occurs as strain relief and abrasion protection.

One other thing.

You mention a pouch. Have you considered how to deal with your power bank if it suddenly self-ignites?

[–] Honytawk@lemmy.zip 0 points 8 months ago* (last edited 8 months ago) (1 children)

Is it possible to make a loop with the cable and put the connector somewhere between the crossing of the cables?

If you tie the cables together at the crossing, all the strain is on the cables, instead of on the connector.

Because as long as there is strain on the connector, all of them will eventually fail.

[–] lemmyman@lemmy.world 0 points 8 months ago

Because as long as there is strain on the connector, all of them will eventually fail.

This is key.

OP needs to secure the cable on each side of the connection, and leave a little slack for the connector.

[–] dgriffith@aussie.zone 0 points 8 months ago (2 children)

Some 3:1 glue lined heat shrink on the backs of each connector might do the job.

The glue melts during heating and with a 3:1 ratio you get quite a bit of glue forced in around the wires as it shrinks. It then sets pretty robustly once you get down towards room temperature.

You could try shrinking maybe some 6 or 10mm heatshrink over approx 25-50mm either side of the connector (with a bit of overlap on the connector) and see how it goes. Fully shrunk it's pretty chunky but it won't be any bigger than the connector.

[–] prex@aussie.zone 0 points 8 months ago (1 children)

Glue lined heatshrink is sometimes called dual wall.

[–] lennyaa@pawb.social 0 points 8 months ago

That could work. I need to find a way to more precisely inject the hot glue at the shrink tubing (shouldn't be rocket science).

I actually did exactly that, but at the 5v to 12v step up module where all the 4 wire pairs leave the module. The step up module for the fans is basically rock solid and that works flawlessly.

[–] Thrawne@lemmy.world 0 points 8 months ago

I might add, if you can, backfill the connector. I put silicone epoxy in the back of my JST connections, and adhesive lined shrink. Those connections are solid.

[–] ragebutt@lemmy.dbzer0.com 0 points 8 months ago (1 children)

jst sm for wire to wire like this, keyed, latching, rated to 3A. Should be easily available worldwide

https://www.digikey.com/en/products/detail/sparkfun-electronics/14574/8543394

You can get them pre crimped like this if you don’t have a quality crimp tool. If you don’t go with this route. If you need to make like 200+ connections consider getting a quality crimp tool and then the crimp ends and housings, bonus there is no potential failure from solder joints (just from bad crimps since you will most likely not buy the 450€ JST WC-240 that is the official crimp tool. Tbf the engineer PA-09, which is what I use, is pretty solid once you get the hang of it and much more reasonable at ~ 30€. They don’t ratchet and they’re slower because they don’t have the wide dies but the crimp shape is very high quality, which matters. Just don’t get the ultra cheap unbranded or noname ratcheting crimpers with shit dies that cost like 10-15€ and give you bad crimps that fail 40+% of the time)

[–] lennyaa@pawb.social 0 points 8 months ago (1 children)

That connector does look robust, the only issue with that are the hard edges. I see now that I should've added that to the list of requirements (my bad). The thing with hard edges is that they can get caught in the fabric which then not only damages the fabric but also pulls on the cable / plug damaging them as well.

About getting quality gear, I fully agree with that, I'd rather spend a bit more if it means it won't break later. If you can find / help me find some kind of round connector that would help me a lot.

[–] ragebutt@lemmy.dbzer0.com 0 points 8 months ago

Wrap with 3m friction tape? Depends on how often you need to plug unplug I guess

This was an interesting dilemma so I researched it a bit:

Apparently some people use brass/tin plated snaps. Conductive and good for low voltage. Sew in and when the suit is put on just snap them together: https://www.adafruit.com/product/1126

Some of these are used in a medical context and actually officially rated for voltage/current if you’re worried about that: https://romed.com/medical-electrical-snap-fasteners.aspx

Alternatively rosenberger makes a series of magnetic snap connectors with softer edges. Pricey though https://www.rosenberger.com/products/connectors-adaptors/magnetic-connectors/

[–] dangling_cat@piefed.blahaj.zone 0 points 8 months ago

JST! You can check out XH, PH, or SH, depending on your needs.