Connectors

Warning: tedious business/technical content ahead. Back in Stumbling & getting up I explained why I was temporarily halting shipment of Stokemonkey kits: the controller enclosure and the electrical connectors in it need improvement.

I should remark that the same connectors are used in electric bike kits (simple hub motors) that cost half — or less — what mine does, and I guess people accept them because kits at that price point attract the kinds of hobbyists who don’t mind a little or a lot of duct tape and solder to make up for the lack of strain relief and proper cable jacketing, and there’s nothing wrong with that, but I’m trying to reach people whose quality expectations are higher.

I said I was going to upgrade to Neutrik Neutricon connectors for the 3- and 5-pin low-current connectors. But now I’m balking at the cost: it’ll cost me $6,000 to get set up with the minimum tooling (2 sets, one on each side of the ocean) and raw stock for 90 assemblies, and delivery is not quite promised for 8 weeks out, and this is before I send it on to China and hope it gets there, that they can figure it out, etc.

I could really use some expert advice. There’s a dizzying array of connector types out there, and precious little unbiased top-level information about how to select the most cost-effective, application-appropriate kinds.

I was leaning hard toward telco-standard RJ-12 type connectors, because tooling and replacement stock is cheap and near-universal, but discovered late that these are inappropriate for the multi-strand conductors used in the wires concerned.

Here’s the other thing: the connectors I use now are subject to early failure mainly because the enclosure is too cramped. If I fix the enclosure (working on it), I might not need to upgrade the connectors at all.

4 thoughts on “Connectors”

  • Bill Manewal

    Here’s my $.01.. Disclaimer: I’m not an engineer. First, I don’t much like the present low-current connectors, regardless of the enclosure they’re in. Mainly because they lack strain-relief and the small screws that secure the clamp to the incoming wire constantly fall out. I’ve been happy with my mod: wrap a gob of gaffers tape around the bottom part of the connector and the wire.

    I don’t really know how to steer you toward something better, but I agree $6K is pretty far north of ridiculous to get set up with Neutrik.

    Perhaps you’re on the right track with a roomier enclosure obviating the need for strain relief. After all, I’ve seen lots of nifty plastic connectors in wiring harnesses of cars and motorcycles that don’t have strain relief. Maybe something out of that market would do the job handily?

    Have you posted your query on other discussion groups, not just motor assisted bike groups but more engineering newsgroups? Might be worth a try.

    I don’t see why Molex connectors wouldn’t do the job. This website says the Minifit series are rated at 9 amps and they come in configurations of 2 to 16 pins. The connectors seem reasonably priced ($1.65 to $6.05), the pins are $7.95 per 100 and the most expensive ratcheting crimping tool is $$68.95. We’re a LONG way to $6K here!

    http://www.action-electronics.com/molex.htm#Mini

    Reply
  • Bob

    I like these Series 1 CPC connectors from AMP. They come in different shell sizes and pin configurations.
    The connectors come without pins installed. You buy the pins separately and crimp them on to each wire and then
    push them into the connector shell. They snap in place.

    http://www.newark.com/NewarkWebCommerce/newark/en_US/endecaSearch/partDetail.jsp;jsessionid=LNC0RXZQ452S0CXDUY2SFGAK2OTCIIV1?SKU=66F6167&N=0

    If you go to the link above(sorry about the huge URL) and click on “catalog page” to see the selection. On this page, click on
    the first “click here” link to see the selection of pins available. The tool that I use to crimp these pins is the Snap-On PWC47

    http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=15632&group_ID=797&store=snapon-store&dir=catalog

    Again, sorry about the huge URL.

    I have had great luck with Newark. Call them for help. Get a catalog from them. Ask for some free samples since you might buy
    lotsa stuff.

    hope this helps!

    Reply
  • Paul

    Todd,

    Maybe if you get the Neutrik, you can defray the startup costs by making custom cable assemblies
    for high-end audio guys like me?

    Reply
  • Sam Powrie

    Hi,
    not sure what your connection requirements are but my Canadian Bionx motor kit has really excellent, waterprrof, rubber-encased connectors very similar (or perhaps identical) to those that were once used for two-wire, high powered underwater flash connectors. You may want to look into these.
    When I get an XtraCycle I’ll come to you for a motor as well!
    best wishes,
    Sam Powrie,
    Adelaide, Australia.

    Reply
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