Connectors

Types

Free Hanging

This is probably the most common type of connector on an FSAE car. These connect wires to other wires, and can interface either with other free hanging connectors or with panel mount connectors. In FSAE these will usually need to be weather resistant. The Deutsch DT and DTM series are popular in FSAE, although many varieties exist.

Panel Mount

Panel mount connectors are used to allow a circuit to interface with the rest of the car. In FSAE these will usually need to be resistant to the weather. They can either be soldered directly to a PCB, or they can be connected to a circuit via wires.

PCB Mount

These are connectors that are soldered to PCBs. They are usually not weather resistant, and are only used inside a housing - either to connect two PCBs, or to connect a PCB to a standalone panel mount connector. They are commonly refered to as JST connectors: however, JST is not a standard but a manufacturer that makes many different families of PCB mount connectors.

PCB to PCB

PCBs can be directly connected together inside a housing without the use of wires. This is usually done for modularity (so that you can use a PCB for multiple functions), interfacing with a premade part (e.g., a microcontroller), or for packaging reasons. Care needs to be taken so that the solder joints on the connectors are not being overly stressed with the weight of a PCB.

OEM Connectors

Often you will not be able to choose your own connectors, and you will be restricted to what the manufacturer of a component decided to use. Many sensors have a connector molded into the housing, as do the coils and injectors on an IC car. ECUs and motor controllers are notorious for having connectors with seemingly millions of pins, and which connector they use should be taken into consideration when deciding on them. Megasquirt 3 ECUs, for instance, use DB37 connectors to interface with the car, which use soldered pins and are usually not waterproof.

When deciding on a component, make sure you can actually buy the connector it uses - often times they can be hard to find (or very expensive). A good source for the rare Japanese OEM connectors is cycleterminal.com - their website seems to have been designed a few centuries ago but their prices are good.

Considerations

Density

Connectors can vary greatly in how close together the pins are. A connector with a higher density will usually be lighter, but they can be harder to assemble.

Connect/Disconnect Cycle Rating

As connectors are connected and disconnected, the contacts and components will deteriorate. The cycle rating is how many times this can happen while still meeting the specifications for maximum resistance and pull force. Many connectors (like board to board connectors) are only rated to tens of cycles, while some (like USB connectors) are rated for thousands of insertions.