Source for Automotive Electrical Connectors

[Pat]

I've noticed scorch marks on a couple of my 30A electrical connectors and figure it it's time to replace any looking suspicious. The wires under load are cool and I figure the cause is corrosion in the connectors themselves. Surprisingly, I've had a bit of a struggle finding suitable OEM-type male and female spade connectors. Most of the ones available at the local auto parts shops are aluminum and I'd really prefer brass or some other metal that has very low resistance and isn't corrosion prone.
Any suggestions for sources?

On a related note, when I was in one of the local parts shops looking for connectors and in discussion two of the mechanics got into the "crimp vs solder" debate regarding wiring. Interesting in that I thought the best solution was to crimp but apparently one quoted my favorite mechanic (Ed China) as solder was the way to go. Any thoughts on that would be also appreciated.

 

[Seymour Snerd]

As a source for high quality terminals I recommend Terminal Town's Electrical Connector Home Page

The founder has an aviation background and is very concerned with the quality of the parts he sells. There is some good general technical information on the site about crimp and terminal methods and quality, eg Terminal Town's Electrical Connector "How To" This is NOT a Crimper!

Regarding the great crimp vs. solder debate, we had a quite a long discussion on this a while back that starts here:
http://www.gt40s.com/forum/gt40-tec...ine-cooling/34783-great-way-splice-wires.html

I think the upshot is that, as usual, there are pros and cons to each, and furthermore they are not mutually exclusive.

The most common con to crimping alone is that there is no non-destructive way to directly determine whether you have a good crimp, although a pull-test according to the terminal specs goes a long way toward that. This means you need to do the crimp very carefully and to use a crimp tool that is properly shaped and sized for the terminal, and can provide sufficient crimping force. One of the interesting things about crimping is that when done properly (i.e. with sufficient pressure and correct geometry) it causes a "cold weld' at the interface between the wire and terminal and thus is capable of providing a very high-quality and reliable connection. Hence their use in modern automobile and aircraft construction.

Solder, on the other hand, is pretty obvious in its forming of a sound electrical connection since it flows in a way that is visually confirmable. The down side is that wherever the solder joint ends there is a stress riser that if not properly strain-relieved can lead to fracture under vibration.

There are some crimp-heat-shrink-solder terminals that combine both methods (what started the thread above) and appear to me to provide all the advantages of both methods. The only downside I've seen to these is that they required localized control of the applied heat in order to prevent over-heating to adjacent insulation and they tend to result in a longer stiffened length of the wire and so require more space on each side of the joint before the wire can bend.

 

[Pat]

Great info Alan, thanks for the input.

 

[JohnC]

Have a look at Anderson Power Products' line of Power Pole connectors. The contacts are silver plated for lowest resistance and they offer up to 75 amps, I think, in a fairly small form factor. These are really good connectors for applications like radiator fans which can pull 4 to 6 times their rated current during starting, and it's these high amperage starting surges that really tax the relays, connectors, fuseholders, etc.

On the crimp vs solder question, this is one of those "religious" areas that has zealots on both sides. IMO, for a high vibration application, a crimp connection is superior to a soldered.

 

[Seymour Snerd]

Great info Alan, thanks for the input.

Glad to return the favor.

 

[Cliff Beer]

Pat, I'm no expert on the pros and cons of crimp v. solder in an aviation environment (probably similar to an automotive environment in many respects) where vibration is a big factor in longevity of the connection...and the risk of failure is very high....but I do know that Boeing used both solder and crimp (and sometime both at the same time) in the old days when traditional bundled copper wiring was used predominantly (not so much any more obviously). I don't know what the criteria was for use of one method v. the other, but you can be sure there was a lot of thought and testing that went into it by a bunch of very smart people with a lot of experience. No doubt each method has better application in different situations, and neither is obviously/universally better than the other.

What I do know a fair bit more about is wiring in a marine environment. In a marine environment, everything is soldered. This is because in a marine environment, vibration is less of a factor (generally) and corrosion is a much bigger factor. The wiring in a boat (often passing in or near the bilge) is subjected to corrosive salt water vapor, or even worse, direct contact with salt water. A crimped connection will have a short service life in such an environment - corrosion will break the continuity where a soldered connection will maintain continuity at that point. For the same reason, marine wiring uses clamped ring connectors at fuse panels and terminus in order to fight the corrosion problem better than with push-on plug connectors.

Personally, for an automotive environment in the rainy Pacific Northwest here I'll be soldering my connections every time.... Results may vary.

 

[Seymour Snerd]

A crimped connection will have a short service life in such an environment - corrosion will break the continuity where a soldered connection will maintain continuity at that point. For the same reason, marine wiring uses clamped ring connectors at fuse panels and terminus in order to fight the corrosion problem better than with push-on plug connectors..

Along the same lines, but regarding the terminal-terminal contact itself, you'll notice that modern automotive connectors (eg Weatherpack) go to some lengths to isolate the terminals from the environment: there is generally a complete seal around both the crimped area and the terminals themselves, using rubber seals, etc. But if like most of us with GT40s you're stuck with blade-type "faston" connectors you probably want to choose terminals that have plastic shrouds around the blade and receptacle, to at least slow down the ingress of moisture and contaminants.

That's also an argument in favor of the ones that use built-in adhesive heat-shrink.

 

[Scott Calabro]

Veek,

If you want some real good choices, check this link out;

Batts Racing Products

As far as aviation is concerned we don't generally use any hand soldered connections any longer.

There are instances where mil-spec heat shrink solder splices are used in repair and modifications, like a wiring service bulletin or Airworthiness Directive.

Cheers,
Scott

 

[Keith Stafford]

As an electronics engineer, we use these daily on our power data loggers, the best way to connect a crimp is to make sure the end of the wire is tinned with solder, if you want to stop the wire coming out solder a small blob (nipple) to act as a plug on the end. Then crimp with crimpers (not pliers). Ensure the wire insulation is NOT stripped back too far, another common mistake, no conductor should be visible. K