I know this is an old thread, but I wanted to add a little.
Bob, excellent write up, but I had hoped you would have expanded a bit on the crimp connectors, especially those that are readily available to the everyday person shopping at Walmart or any auto parts store.
I have done a ton of wiring in my time (I used to install competitive automotive sound systems), and have crimped literally thousands of connectors. Here are a few things I have found:
0. Crimp connectors are ONLY to be used on stranded wire! You MUST solder single-strand wire! Luckily, I don't believe that there is any single-strand wire used in any automotive or marine application, so you shouldn't run into any.
1. Typical crimp connectors have a split in the metal sleeve. Look in the end of the connector, and you usually will find it.
- In the case of a spade or ring (what Bob calls "terminal end"), the split will be on the "top" of the connector (in other words, the portion of the sleeve that elongates into the ring or the spade is NOT the split side).
- In the case of bullet connectors (Bob did not show an example, but they look just like what they are called; I have uploaded a pic below as an example), it is the same as the spade or ring, with the added bonus of being able to see the split on the bullet portion of the connector easily.
>>Tangent: When dealing with spade or bullet connectors, the "rules" (such as they are) typically state that the POSITIVE wire is terminated with the female version of the connector, because these are usually covered with insulation and are therefore protected from contacting ground when disconnected and flopping around in space. This is also true for the same reason in speaker wiring: the POSITIVE side of the source is female and the NEGATIVE side of the source is male. Therefore, the opposite is true for the leads coming from the speaker.
- In the case of a butt style connector, normally there is a small "dimple" in the center of the sleeve; that dimple is exactly opposite of the split, so is a good indicator of where the split is. Sometimes there is writing on the outside of the connector: it may be on the "split" side of the sleeve, or it might be on the "dimple" side of the sleeve. It may be able to be used as an indicator so you don't need to check every connector...
The location of the split will become important shortly...
2. Strip the insulation just to where the visible wire is as long as the edge of the metal to the dimple in the butt style connector, or extends to the exposed end of the sleeve in the other cases. In other words, you want the wire insulation inside of the connector insulation, but not inside the metal sleeve, and the wire to touch the dimple or extend to the end of the exposed end of the sleeve. After a little trial and error, you'll find the perfect length of the strip. Twist the wire strands so that there is no way you can have any strands escape the connector.
3. Before inserting the wire into the connector, I have found that adding a good amount of either silicone grease or No-Ox-Id conductive grease into the connector and on the exposed wire greatly improves the ability of the connector to resist weathering and corrosion, and pretty effectively waterproofs the connection.
4. Fully insert the wire into the connector.
5. On the "normal", consumer-grade crimper, there is a "non-insulated" crimp area. There is a concave side and a convex side, that when closed, the opening is shaped into a "U". You want to put the connector into the crimper, positioning the non-split side of the sleeve on the convex side and the split into the concave side, so that the non-split side is forced into the split side. This allows the connector and the wire to form to each other and create a better connection.
6. Crimp the "edge" of the insulating jacket to the wire insulation.
7. For further waterproofing, use heat shrink, or even better, adhesive-lined heat shrink, fully covering the connector insulation and extending onto the wire for 1/4" to 1/2". The adhesive-lined heat shrink will add some lateral strength to the connection as well. On rings and bullets, you can shrink to the edge of the connection or even over the connection, and trim back enough to allow connectivity. You should use the silicone grease / No-Ox-Id between the mating surfaces on bullet, ring, and spade connectors as well to increase life and reduce oxidation. Also use the grease on your cleaned battery connections to eliminate corrosion.
A final note: Whenever possible, select the connectors that have insulation over the mating surfaces (in the case of bullet and spade connectors). These are also usually insulated using nylon, not vinyl, and may cost slightly more: they are worth the extra cost! Some even have heat-shrink already bonded to the sleeve. Though, I still prefer a separate layer of adhesive-lined heat shrink.
Hope this helps and expands on Bob's awesome write up.
I'm not overweight, your aspect ratio is wrong!
Last edited by dl_sledding : 05-12-2014 at 11:24 PM.