Open Barrel vs Close Barrel Crimp Terminals

wlai

New Member
Hi:

I'm trying to buy the right tools and connectors for building solar PV system. Going to start with a system for my boat, and then work my way up to a home system. I've tried the Closed Barrel terminal when I was building a cable for my car, but it required borrowing a hydraulic crimper from a friend. Not knowing what I was doing, it came out "wonky" as the wire wasn't thick enough for the barrel, I crimped too hard, and the crimp came out lopsided and ugly, and the barrel metal actually tore. It held up ok so far but I am sure it was either technique or the barrel not being the right type.

I'm wondering if Open Barrel terminals can be used instead? It seems easier for me, doesn't require a hydraulic crimper which is easier for me to judge how well it's crimped. Is it any less secure?

And can you recommend me the best connectors and crimper to get, with links? I dont' want to blow my budget on the crimper so Chinese ones or HF ones are my budget point. Thanks!



cbob.PNG
 

Bob B

Photon Sorcerer
For a marine environment in particular ... I would be using the terminals that are closed on the end.

For the size wires you are probably working with, Harbor Freight sells a hydraulic crimper that is pretty good and not very expensive .... especially if you catch a sale.

To get a pretty crimp, the terminal and wire are going to have to be sized pretty close .... if you buy the wire and terminals from the same place, you have a better chance of getting a match .... dies do vary somewhat and you may have to go up or down a size.

It would also be good to use marine heat shrink that has some glue like stuff in it that seals the ends.

Ancor makes some pretty good stuff.
 

time2roll

Photon Sorcerer
How large of wires? MC4 connectors? Large battery lugs?

Some can be ordered pre-made for a pro crimp with best tools.
 

leadman

New Member
For marine use make sure you keep all electrical wiring run isolated from the hull. We had a father and son killed here at a marina when a boat electrified the water where the son jumped into then the father tried to rescue him. Sad.
We used to used the closed end terminals on battery cables but would strip the wire end to fit tight in the terminal then "tin" it. We would then melt solder in the terminal to the almost the top and stick the wire in the terminal while hot. Sealed the wire at the terminal to prevent corrosion this way. Buying a crimper and using shrink sleeving might be easier.
 

Short_Shot

Photon Sorcerer
Oh I love this topic.

The only thing is would add here is to watch out with the "closed" type and the "indentor" style crimp tools. By closed I mean as shown above with a barrel that goes through.

blue-nylon-insulated-with-insulation-grip-ring-terminals.png
These come in insulated and uninsulated types and the insulated ones like this should use special crimpers designed with insulation in mind.

There is another type of "closed" end connector that seals the end of the wires from the elements. I assumed this is what some folks are calling "closed" and is what I prefer, but I'm not sure if they're available in smaller sizes.

Screenshot_20210719-045821_Chrome.jpg


Most (all?) of these "open end" barrel type connectors have a seam in them and if you crimp down on this seam with the "indentor" side of the tool it often splits it open for a weak crimp.

I actually had to write a procedure for my guys here at work due to this. We kept having the wires pull out when crimped that way using their cheap crimpers they have in their tool boxes.

I happen to have the photos I took for this document handy. I used crappy old uninsulated terminals we weren't using anymore and intentionally used slightly undersized wire. This is for a low voltage limit switching application that our setup guys need to deal with often.

I also intentionally crimped them wrong way around on the wire for the sake of photos.

Please note that none of this would be appropriate for a marine environment, however the results of the crimp can be similar.

WIN_20210719_04_32_37_Pro.jpg
Note the seam.

When this is put against the indentor:

WIN_20210719_04_33_22_Pro.jpg
WIN_20210719_04_33_42_Pro.jpg

I see my guys do this nonsense all the time and half the time they just leave it that way.
Even when squeezed as hard as they can this wire will still pull out in short order.

(This one was also used to illustrate incorrectly putting insulation into the crimp - ignore that!)

WIN_20210719_04_34_01_Pro.jpg

Now. That kind of thing is pretty stupid. Most people know not to leave it that way. So the next thing I see them do is try to re-crimp it:
WIN_20210719_04_34_23_Pro.jpg

Then this is the result. These still also pull out constantly. It's also hideous.
WIN_20210719_04_34_37_Pro.jpg

So this is why orientation is important when crimping these kinds of small terminations.

At any other angle it's hit or miss. Sometimes it's neat, sometimes it splits.

When done right, seam opposite the indentor. This is also normally the side away from the body of the connector.
WIN_20210719_04_35_32_Pro.jpg

Notice the seam doesn't split wide open.

Again ignore the poor placement of insulation (and upside wire) Should be a more snugly placed against the barrel of the crimp.

Normally the wire breaks long before this ever pulls out.
WIN_20210719_04_36_31_Pro.jpg

Now I just need to get this place to start buying more appropriate terminations and cord sets for the application but that's a different rant....
 
Last edited:

wholybee

Solar Addict
For up to at least 10AWG, and sometimes 8, you don't need a hydraulic crimper. A good ratcheting will work fine. You need to use the right sized terminal for the wire, and the right die for the terminal. There are different dies for terminals with shrink and and non-shrink terminals, and for non-insulated terminals. So look for a Crimper with a selection of dies, and make sure it has those three. In particular, the die for shrink terminals is hard to find. They will usually also have a die for open barrel. If you use the wrong die, you will not have an ideal crimp.

The non shrink die makes 2 crimps of different sizes, (called double crimp) and the shrink connector die makes only a single crimp, and is designed to not damage or tear the heat shrink insulation.

I use an older Ancor tool, which is different from what Ancor currently sells. Mine is very similar to the Wirefy Crimping Tool Set 8 PCS found on Amazon.

Open barrel terminals are usually used for connector pins. Wire lugs are closed barrel.
 

Short_Shot

Photon Sorcerer
For up to at least 10AWG, and sometimes 8, you don't need a hydraulic crimper. A good ratcheting will work fine. You need to use the right sized terminal for the wire, and the right die for the terminal. There are different dies for terminals with shrink and and non-shrink terminals, and for non-insulated terminals. So look for a Crimper with a selection of dies, and make sure it has those three. In particular, the die for shrink terminals is hard to find. They will usually also have a die for open barrel. If you use the wrong die, you will not have an ideal crimp.

The non shrink die makes 2 crimps of different sizes, (called double crimp) and the shrink connector die makes only a single crimp, and is designed to not damage or tear the heat shrink insulation.

I use an older Ancor tool, which is different from what Ancor currently sells. Mine is very similar to the Wirefy Crimping Tool Set 8 PCS found on Amazon.

Open barrel terminals are usually used for connector pins. Wire lugs are closed barrel.
Excellent point.

I forgot to include that having the right crimper in the first place pretty much eliminates any of the nonsense in that last post of mine.

It's just that so many people only have that type of crimper and that's all they care to spend money on.

That said, a lot of lugs have open ends. I have thousands of high temp ones here that I use pretty often - though I have the appropriate crimper for them.
 

wholybee

Solar Addict
Oh I love this topic.
Yikes, those are bad. A good read for you guys at work:

They need to buy better tools, and if you can get them better connectors too.
 

toms

Solar Addict
I worked in the Automotive manufacturing environment for a long time. Small wires were universally joined with open barrel terminals. The correct crimp tool is essential - i use Iwiss crimpers.

For my off-grid systems, all small wires get open barrel terminals with heatshrink or Deutsch terminals.

For large wires the lugs and hydraulic crimper are the go, also with heatshrink.

I wouldn’t ever use pre-insulated terminals in a critical application.
 

Short_Shot

Photon Sorcerer
Yikes, those are bad. A good read for you guys at work:

They need to buy better tools, and if you can get them better connectors too.
Well.

Unfortunately it's max of 24 volts under 10ma.
Its just used for limit switches. We also stock the terminals and switches for a production job so they're always available.

That's also why nobody ever wants to spend the money to upgrade the method we use.

There's never any problem if they just take half a second to rotate the terminal properly in the crimper, even if they use the worst crimper on the planet.
 

12VoltInstalls

Solar Addict
I wouldn’t ever use pre-insulated terminals in a critical application
When nothing else is available I buy them. Then use two pairs of strippers to twist of the plastic sleeve LOL

They make very nice ‘preinsulated’ terminals with heat shrink sleeves. Except that the sleeve gets punctured and split if you crimp properly; what’s the point?
 

wholybee

Solar Addict
When nothing else is available I buy them. Then use two pairs of strippers to twist of the plastic sleeve LOL

They make very nice ‘preinsulated’ terminals with heat shrink sleeves. Except that the sleeve gets punctured and split if you crimp properly; what’s the point?
Then you didn't crimp properly or used the wrong tool. Heat Shrink terminals require a special tool or die, which will not puncture or damage the heat shrink. I use them almost exclusively, except when they are not available.

Insulated terminals also use a different die than non-insulated, and if you use the correct die, you won't need to twist off the plastic. The correct die will crimp the plastic in two places at 2 different diameters. One crimp is the electrical connection over the barrel, the second is slightly larger and crimps the insulation of the terminal to the wire insulation. The correct die on a good insulated terminal works very well.
 

toms

Solar Addict
This is a picture of a good open barrel crimp. By looking at the shape of the ears after crimping i can tell if the crimp looks like this inside.

I cannot see what an insulated terminal crimp looks like on the inside because the insulation masks the terminal material.
 

Attachments

  • DD936CC3-2D6E-490A-897C-FAB61A8D418D.jpeg
    DD936CC3-2D6E-490A-897C-FAB61A8D418D.jpeg
    71.6 KB · Views: 13

Short_Shot

Photon Sorcerer
This is a picture of a good open barrel crimp. By looking at the shape of the ears after crimping i can tell if the crimp looks like this inside.

I cannot see what an insulated terminal crimp looks like on the inside because the insulation masks the terminal material.
That's perfect!

That's what it looks like with the proper crimper. Unfortunately the cheap "indentor" ones described above perform exactly the opposite way and push each side apart.
 

Just John

Photon Sorcerer
I will say that up to 8 gauge, I use strictly heatshrink connectors (Ancor is the 8 gauge brand, Wirefy for everything smaller) with tinned wire (Ancor again). Anything 6 gauge or larger, I use hydraulic crimp tool, although I have found for Anderson pole connectors (8 and 6 gauge) work well with just a mechanical crimp tool. The Anderson connectors have extremely thick barrel walls, and are silver plated copper. The thick walls make them hard to crimp properly without getting "wings". I would strongly encourage tinned wire and connections even if you aren't on a boat.


I bought a cheap hydraulic crimper, and after enough ears, went for the expensive set with half gauge sizes. (If anyone wants the cheap tool, let me know, you pay for shipping and it's yours).


I love the heatshrink connectors, but as already mentioned, you REQUIRE the correct die to crimp them. Up to 10 gauge, takes about 1 minute to strip and crimp a perfect connection every time. I use the Katapult (Klein) stripper for up to 10 gauge that Will recommends.


For 8 gauge and smaller heat shrink ONLY.


For 10 gauge and smaller, this works better (surprisingly better than the Ancor).


The Wirefy (and Wirefy connectors) is really easy to use and makes a perfect crimp every time. You may wish to buy the set with multiple die sets, now I wish that I had. In particular for balance/sense leads on the BMS, the heatshrink connectors are the way to go.

If it isn't heatshrink, I only use the closed barrel lugs that are tin plated, Ancor makes superior ones in my opinion (compared to the Selterm on Amazon). The Ancor brand wire it top notch too.

 

12VoltInstalls

Solar Addict
Then you didn't crimp properly or used the wrong tool. Heat Shrink terminals require a special tool or die, which will not puncture or damage the heat shrink
Whatever. You didn’t read what I wrote.

A proper crimp isn’t merely a crushed barrel with some mechanical retainment. You need 100% electrical contact. Only the bare hex-swage and B-crimps dependably and repeatedly do that. Then there’s weather-tite to consider.

I think everything else is either lazy/ignorant or a compromise. There ain’t no plastic sleeve crimp terminal that I’ve ever seen in the field that meets that test. It’s so easy to just use the right parts and get a perfect B crimp and put heat shrink over it - why bother with a compromise?

I have several crimpers: three terminal crimpers, two different MC4 barrel crimp tools, and a midsize changeable-jaw barrel and terminal crimp for bigger terminal lugs, and a battery lug crimper. A couple strippers I like from Klein have the “insulated terminal” (sic) crush-crimp capacity but I never use that feature.

You would probably be surprised at how many ‘factory’ trailer harnesses use the heat-shrink terminals. When the green crud starts growing under the heat shrink sleeve it’s nearly always over the barrel. Why is that? The heat shrink doesn’t generally fail. So it’s reasonable to conclude the “proper” crimp over heat shrink from the factory is what created the failure. Maybe the failure rate is acceptable in manufacturing but ‘we’ aren’t trying to make 10,000 crimps a day so the loss of 10 seconds to crimp bare terminals and heat shrink over isn’t a concern.

(I live in ‘the rust belt’ which is an awesome demonstrator of the efficacy of electrical connectors on vehicles and trailers. You just won’t ever convince me after what I’ve seen)
 

JoeHam

Photon Sorcerer
For up to at least 10AWG, and sometimes 8, you don't need a hydraulic crimper.

You can go much larger than that without hydraulic:


This was about 40% cheaper with a lifetime warranty a couple of years ago. ☹️

I’ve only used up to 2 AWG so far and I add shrink tubing with glue to all crimped connections.
 

Short_Shot

Photon Sorcerer
You can go much larger than that without hydraulic:


This was about 40% cheaper with a lifetime warranty a couple of years ago. ☹️
Lol yeah but for that price you can get hydraulic ones.
 
Top