Molex SL Connectors

[ThadHouse]

With SystemCore using MolexSL everywhere, here's some links to all the crimps and connectors.

For plugging into SystemCore:

Female Terminal
https://www.digikey.com/en/products/detail/molex/0016020102/115053

2 Pin Housings (RSL)
https://www.digikey.com/en/products/detail/molex/0050579402/115029

3 Pin Housings (SmartIO)
https://www.digikey.com/en/products/detail/molex/0050579403/115034

4 Pin Housings (I2C)
https://www.digikey.com/en/products/detail/molex/0050579404/115057

Below are the male terminals and housings, used for making extension cables:

Male Terminal
https://www.digikey.com/en/products/detail/molex/0016020114/171961

2 Pin Housings (RSL)
https://www.digikey.com/en/products/detail/molex/0701070001/210968

3 Pin Housings (SmartIO)
https://www.digikey.com/en/products/detail/molex/0701070002/210969

4 Pin Housings (I2C)
https://www.digikey.com/en/products/detail/molex/0701070003/210970

[truher]

Has anyone had good/bad experiences with the "high force" versions of the female pins? This is series 71851 rather than the 70058 you linked here.

https://www.molex.com/content/dam/molex/molex-dot-com/products/automated/en-us/productspecificationpdf/704/70400/PS-70400-001.pdf

[ThadHouse]

With the locking connector, I don't imagine its necessary, but might be good for someone to test if they're willing to buy them.

[ryan-reed-3647]

I've used the high force contacts before on the RoboRio. I think they provide decent utility when using the connectors without retention (like the header pins on the RoboRio) but other than that I don't think there's any advantage. The regular version is rated for 50g shock with less than 1us discontinuity, so I don't see much to improve there either.

[gerth2]

I ordered a pile of the For plugging into SystemCore ones, should be here this weekend and will start assembling some cables.

Sample size of the RSL, I think the pin size and spacing is sufficiently backward-compatible with the RIO that, at least to get started, you can still plug your old PWM wires in - awesome feature, especially for teams with a lot of hardware sitting around.

[Kevin-OConnor]

Correct, Molex SL should be pin compatible with most "PWM" style cabling, just without the benefit of keying and latching. Because of some combination of the pin sizing and individual connector housing, I anecdotally see substantially higher retention forces with standard PWM cables I have here in my office than on roboRIO.

[hamster1147]

Are you guys using the official Molex crimpers spec'd for those pins or are you using generic crimpers?

We don't have the crimpers for SL pins, so we're looking into buying premade female to female cables and soldering our cables onto them. Since some FRC/FTC teams will probably go down this route to avoid crimping their own cables, its probably worth us testing out the idea.

https://www.molex.com/en-us/part-list/216270?currentPage=2

[Kevin-OConnor]

I think teams getting SL socket-to-socket or socket-to-flying-lead cables like that and connecting them directly to sensors, soldering to other cables, or using other connectors they are more comfortable with are all options I expect various teams will explore/use.

I've done, and had students do, Molex SL and other similar .1" pitch pins with:

• Ratcheting crimper with no contact positioner (you can find various models for similar pins from IWISS, Klein, etc. in the $25-50 range). I'll leave it to people more knowledgeable than I to point you towards the ones that will make the most similar crimp to the correct SL tooling.
• Ratcheting crimper with a contact positioner (very similar to the service grade Molex tool: https://www.digikey.com/en/products/detail/molex/0640160201/2074098)
• The "premium grade" Molex SL crimper that was offered in FIRST Choice in recent seasons (https://www.molex.com/en-us/products/part-detail/638118700)

I could make serviceable crimps with all 3, but definitely would definitely mess up like 10% or more with the ratcheting crimper alone. There were very few students I would have even bother attempting that. I would not recommend this. If you need to go a low cost route, search over on CD or on Printables for a contact positioner for Molex SL to 3D print and buy the tool it's designed to work with.

With the contact positioner tool I could make them much more easily and had a couple students I would trust to do them with a check by a mentor. I wouldn't have much of an issue recommending other teams use the service grade tool and maybe one of the DIY contact positioning solutions (haven't tried one myself to be sure). With the premium crimper they were even easier and nearly any student on our electrical team could do them.

I don't think Molex SL is substantially different than most other similar .1" pitch pins in this regard.

[ryan-reed-3647]

I would definitely try to get the crimper in FIRST Choice, but we've also had a lot of success with the 3d printed positioner I designed + $25 IWISS SN-2549 that @Kevin-OConnor mentioned. The students use them interchangeably, with a slight preference towards the generic over the Premium Molex crimper (which to me makes them a little crazy but mission accomplished I guess)?

I also personally use it a lot at work and at home and have had very good success with it.

[Paradox-eMentor]

I've updated and corrected the connector part numbers in the attached spreadsheet from the SystemCore Specification dated June 15 2025. It includes links to the datasheets for each part. If you follow the links, there are also 3D models available. The SystemCore now uses gold plated connectors. To avoid corrosion due to dissimilar metals (pointed out in the SoCal SystemCore workshop), all cables connectors should also be gold (Au) plated. I've used all 0.75 μm Au pins in the attached table for reliability. If people are interested, I can update with the 0.38 μm Au plated pins.

Notes:

1. The current cable specification on the SystemCore Testing GitHub calls out all Tin (Sn) plated connectors. Also, the current SL connector kits from Molex are Sn plated contacts.
2. The Beta SystemCores have Sn plated pins on the Smart I/O and I2C ports. Strongly recommend using Sn plated contacts on your connecting cables. If you use Au plated contacts, the Sn will contaminate the Au plating and when you later hook up the production released SystemCore you again risk corrosion.

Molex Connectors for SystemCore.xlsx