Wire Connectors

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PSLimo

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Hey Guys,

I bought some wire connectors for my electronic bay on Amazon and had one fail on a flight. Fortunately it failed after the main chute deployed.

I've always hard wired directly and now I'm thinking it might not be worth the plug and play convenience.

Here's a picture of the type of connectors I was using as the wire gauge fits the screw terminals on electronics.

What rock solid connectors are you guys using in your eBay's that have never had an incident?

Thanks in advance,

Phil
20210612_164746_resized.jpg
 

OverTheTop

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Those red connectors are JST RCY-series. I have had a couple of those fail and had to be replaced (not flight-related problems). I have not looked at the data sheet to see how many insertions they are rated for yet. Beware of the female pins fobbing out.

On face value the JST XH series seems to be more robust.

If you are looking for other connectors have a look at Molex microfit 3.0 or their nano-fit range maybe. We use a lot of Molex in our spectrometers and see very few problems.
 

mtnmanak

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I have been using these 3M 3 & 4 pin connectors from Mouser for years. I like them because they have a strong compression lock on the wires and the snap connectors have a spring arm to give you a positive connector lock. I do also wrap a small piece of masking tape around them after I have connected them, though (shown in pic below). Better safe than sorry.

The down side I can see is that they are extremely expensive compared to other connector options, but on the other hand, for a rocket I am going to spend hundreds or thousands of dollars on, $10 worth of connectors doesn't seem too bad. Costs do add up everytime we say that though :).

Again, these are what I have been using, there may be much better solutions out there, but these have worked for me.





PXL_20210614_111540496.jpg
 

OverTheTop

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I have been using these 3M 3 & 4 pin connectors from Mouser for years. I like them because they have a strong compression lock on the wires and the snap connectors have a spring arm to give you a positive connector lock. I do also wrap a small piece of masking tape around them after I have connected them, though (shown in pic below). Better safe than sorry.
3M are quality connectors too. Positive retention is great for rocketry. Note that those insulation displacement connectors (IDC) need to have the correct wire to form reliable connections. If you conform to the requirements in the data sheet you will have no problem. Go outside those specs and all bets are off with IDC. I am not saying they are bad and not to use them, just something else to be careful about :).
 
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mtnmanak

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3M are quality connectors too. Positive retention is great for rocketry too. Note that those insulation displacement connectors (IDC) need to have the correct wire to form reliable connections. If you conform to the requirements in the data sheet you will have no problem. Go outside those specs and all bets are off with IDC. I am not saying they are bad and not to use them, just something else to be careful about :).
Great point on the wire selection, should have mentioned it. If you look at these connectors on the Mouser site, you will find many, many versions for specific wire gauges and types. The connectors I linked are the ones I use with the wiring I tend to buy and use. You should definitely match up the proper connectors to the wires you use.

One thing I like about Mouser's site is that you can use the column filters at the top of the page to narrow down what you are looking for. If you go to their "Header Connectors & Wire Housings " page, you can put in the parameters for connectors you are looking for and come up with thousands of options.

 

PSLimo

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"What was the failure mode?"

The connection didn't fail it was the wires coming loose inside the connector.

I'm thinking the were just cheap after market connectors and I'm looking for members that can point me in the right direction on a quality product from experience. Gone are the days when you could just walk into a brick and mortar hobby shop and see them in person.

Phil
 

PSLimo

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Thanks for all the input.

I looked up the suggested JST XH on Amazon and right below the real connectors were the cheap knock-offs I bought, lol. I guess you get what you pay for.

Screenshot_20210614-090707_Samsung Internet.jpg
 

bobbyg23

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I have never had an original JST connector fail. I have seen the cheap knockoffs fail though. I get mine at my lhs.
 

MidOH

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Stick with that plug. Just get one that isn't junky. Replace it as needed.

You can also solder on another set of wires, so that you have two of those plugs.

Redundancy incase one fails. You'll have to pull both plugs to remove the battery for charging, but with two plugs, you could also just leave one connected and charge up through the other. That's how I charge my nitrobuggies Rx pack. Unplug the redundant plug and plug in the charger. One plug gets all of the wear and tear of being plulled on.

Try an actual JR or Sanwa plug from A Main Hobbies or such. That connector is the only thing that keeps my nitrobuggy from losing control and nuking a $500 engine.
 

cerving

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JST-RCY connectors are quite robust IF they're the real thing. The ones on eBay are cheap Chinese clones, they often have a lot of slop in the connectors, and (even worse) the wires can sometimes be easily pulled out of the connectors. The remedy is to tape them together, and either tape or epoxy the wires into the connectors, and securely fasten the connectors and all wiring to the sled so they can't move in flight. Masking tape (the brown stuff, not the low-tack colored stuff) is your friend.
 

PSLimo

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You guys were a 100% correct.

Looks like I had the cheap spin off version. I just received the real JST connectors, zero play and a solid fit.

Once again, I guess you get what you pay for.
 

OverTheTop

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OverTheTop

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The remedy is to tape them together, and either tape or epoxy the wires into the connectors, and securely fasten the connectors and all wiring to the sled so they can't move in flight.
Careful with epoxying the wires into the connectors. Some types of connectors rely on the metal pins being able to float in the housing somewhat to assist with mating and improve contact resistance.
 

rocket_troy

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I've also had a few cheap Chinese JST connectors fail. Unfortunately, one was in a flight. The failure point of my ones was always the wire, not the actual connector which is why I'd suggest that if you do purchase wired JST connectors from China, that you purchase the *silicone* wire flavours, *not* the rigid PVC insulated or whatever material they are as they tend to have internal wire configurations that are larger diameter strands with minimal strand count making them prone to work hardening and failing at the bending points - generally right next to the connector.
For a while now I always crimp my own using *Hobbyking* silicone wire. There's probably equal quality silicone wire available in the US, but not online from Ebay or Aliexpress. You want maximum strand count for whatever gauge you've selected for maximum flexibility and reduced likelihood of failing from work hardening or fatigue.

TP
 

SharkWhisperer

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I've also had a few cheap Chinese JST connectors fail. Unfortunately, one was in a flight. The failure point of my ones was always the wire, not the actual connector which is why I'd suggest that if you do purchase wired JST connectors from China, that you purchase the *silicone* wire flavours, *not* the rigid PVC insulated or whatever material they are as they tend to have internal wire configurations that are larger diameter strands with minimal strand count making them prone to work hardening and failing at the bending points - generally right next to the connector.
For a while now I always crimp my own using *Hobbyking* silicone wire. There's probably equal quality silicone wire available in the US, but not online from Ebay or Aliexpress. You want maximum strand count for whatever gauge you've selected for maximum flexibility and reduced likelihood of failing from work hardening or fatigue.

TP
And know what kind of wire you're actually getting. A lot of the Amazon/Ebay sellers are selling cheap Al wire as "tinned copper" (except they apparently forgot the copper). Or copper-clad Al being sold as tinned copper or pure copper, or not specified. Al wire is junk.

Recently got some Jeep foglights off Amazon with decent plug-to-housing 16 gauge pure copper wiring but their supplemental teensy-gauge wire to connect to marker lights is like high-resistance 22 gauge Al, which got tossed. Even though it's only powering LED marker lights, dropping wire size and quality (and increasing resistance with crummy Al prone to breakage) is asking for an engine fire....
 

rocketcharlie

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I would like to see a picture of an AV-bay using these. I'm not clear on where and how they are used.
 

OverTheTop

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FYI, these connectors do a very good job of crimping a range of connectors, including many of the popular JST series. I use mine frequently.
 

MidOH

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Keep in mind that your battery end still has a Chinese connector. Nothing you can do but hack it off and solder a legit JR connector on.

The battery plugs that are actually little balancer type plugs......seem to be OK. Those are the ones that plug directly into the mini boards. I hate those. I wish altimeters gave us solder tabs, not plugs and sockets. I've never had this style of plug fail, other than read a little low on a pin in RC:

 
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mtnmanak

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I would like to see a picture of an AV-bay using these. I'm not clear on where and how they are used.
Here are a couple examples:

In both cases, the connectors are used to allow one of the bulkheads to be removed and the sled to be slid out of the bay from the other side. So, to assemble, you slide the part with the sled into the ebay first, then connect the wire connector from the other bulkhead and secure the bulkhead to the all-thread.

PXL_20201201_040314910.jpg


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tOD

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As mentioned in a previous post you can get these pre-wired pairs from Binder designs/Doghouse Rocketry. Two position, $4.00, four position $6.00. Many colors available. They also sell matching color wire end ferrules.
PXL_20210618_110711747.jpg
 

Brent

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As mentioned in a previous post you can get these pre-wired pairs from Binder designs/Doghouse Rocketry. Two position, $4.00, four position $6.00. Many colors available. They also sell matching color wire end ferrules.View attachment 469316
They work great and it is time to stock up again but I am not going to pay 19.00 shipping for 10 connectors that would fit in a small flat rate 8.45 shipping box. The last time I ordered was from the previous owner. I still have a few left but out of certain colors.
 

caveduck

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After seeing problems like these with the preassembled JST-RCY clones I started making up my own with shells and pins from Digi-Key and the Engineer Inc. crimpers with good silicone insulated wire. No problems since and the cost is ~35 cents per M/F pair. I've even seen the Hobby King connectors with reversed colors on the wires...yikes. Have not had too much trouble with the connectors on mainstream RC batteries.
 
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