# Wire Connectors

### Help Support The Rocketry Forum:

#### PSLimo

##### Well-Known Member
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?

Phil

#### UhClem

##### Well-Known Member
I use Deans Micro 2X for charges and the 4 pin version at the altimeter. Dave Schaefer told me about those some twenty years ago.

#### OverTheTop

##### Well-Known Member
TRF Supporter
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

##### TRA & NAR L2
TRF Supporter
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.

#### Bat-mite

##### Rocketeer in MD
Doghouse Rocketry A division of Binder Design. Excellent wiring, among other cool things.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
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

##### Well-Known Member
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

##### Well-Known Member
TRF Supporter
Just searched the JST data sheet for the RCY connector and there is no mention of the number of mating cycles they are rated to . Their design does look to be quite robust though, so I suspect my problem was with a clone part.

FYI, there is some good information and opinion here that you might find useful:

#### OverTheTop

##### Well-Known Member
TRF Supporter
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

##### Well-Known Member
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

##### Well-Known Member
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

##### Well-Known Member
TRF Supporter
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

##### Well-Known Member
TRF Supporter
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

##### Well-Known Member
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:

Last edited:

#### mtnmanak

##### TRA & NAR L2
TRF Supporter
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.

#### tOD

##### Sinking in the quicksand of HPR
TRF Supporter
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.

#### Brent

##### Well-Known Member
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

##### semi old rocketeer
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.