Need advice for high current spade connector

Discussion in 'The Projects Forum' started by TSmith, Jun 29, 2015.

  1. TSmith

    Thread Starter Member

    Sep 21, 2010
    57
    2
    I'm repairing a mobility scooter that burned up the speed controller because of a poor connection in the spade connectors that power the motor. The motor is a 24V, 13A, 700W, DC motor. The speed controller is a 160amp controller. There are four 1/4" male spade connectors on the controller that connect to the motor. Two connect to the positive lead and two to the negative lead. It is splitting up the current between the 4 connectors. Due to vibration the connectors got a little loose over time, started to arc, etc., and fried the controller. I don't want that to happen with the new controller given it's quite expensive.

    Does anyone have advice on where I can find high quality female connectors that will provide a very secure and tight connection? I don't trust to use the generic automotive spade connectors. That is what was on there before and got loose. Any suggestion appreciated. Thank you!

    IMG_0249s.jpg
     
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,542
    2,369
    You not only require the correct female mating connector (wire gauge) but also a suitable or professional crimper, with these you normally would not have a problem.
    A few makes, Tyco is one.
    Max.
     
  3. paulktreg

    Distinguished Member

    Jun 2, 2008
    611
    120
    You can buy female connectors that "lock" into the holes on the male connector but yours don't appear to have any?

    I would suggest all you can do is buy standard connectors and squeeze them a little tighter with pliers before pushing them on. Could you apply some solder for a more permanent solution?
     
  4. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    Best I could find were rated at 24 amps each. Steel with nickle plating (instead of tin).
    They were called, "high temperature".
    The 700 watt load is less than 14 amps(each), so 2 should do it, especially if you solder the squeezy part after you crimp it.
     
    Last edited: Jun 29, 2015
  5. TSmith

    Thread Starter Member

    Sep 21, 2010
    57
    2
    I normally solder the wire to the crimped connectors. But the problem was with the female connectors getting a little loose over time and I think it increased the resistance and temp went up melting the solder in the speed controller to the connectors. I was wondering if there are some beefier higher quality spade connectors that are more resistant to loosing up over time.
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    Start with a high quality connector brand such as Panduit Panterm, then use a controlled cycle crimper (I recommend the PA8000 from Greenlee) on properly prepared wire. Do not solder as this defeats the flexibility of the stranded wire. Make the connection once and leave it connected since these connections become significantly weaker with repeated disconnections.

    Looking at your picture I see that your unit is intended to mate with automotive type multi-terminal block connectors. I think you can get those from Molex or TE Connectivity.
     
    Last edited: Jun 30, 2015
    TSmith likes this.
  7. mcgyvr

    AAC Fanatic!

    Oct 15, 2009
    4,770
    970
    "faston"/quick connects are typically available for .032" thick male blades or .020" thick (.250" or .187" or .110" or .093" wide)
    measure yours and try the .020" rated ones.. They can be quite snug..

    Of course that connection was intended for the proper multipole mating connector with locking tab.. not just loose piece quick connects.

    Do all you can to provide mechanical securement for the wires to avoid/minimize vibration. cable ties,etc...


    I just repaired a voltage regulator on a Kubota tractor that had the same problem.. One of the terminals in the connector went bad too.. I simply replaced with loose piece quick connects removing the whole multipole connector.. Works just fine now.. For how long we will see...
     
  8. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Solder the wires onto the blades
     
  9. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    :eek:
    Risky, but effective.
    If you're as good with a soldering iron as I am, you can do it without un-soldering the male parts.
    (Nobody likes their male parts un-soldered. :()
     
    shortbus likes this.
  10. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    I've done it several times, never knew I was performing a risky operation ;)
    Maybe I'm just lucky, thought it was trivial.
    Hot iron, work fast. But that's how I do everything.
     
  11. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    Translation of myself: Those fins must be connected to something under that potting compound. I'll bet the connection is soldered, and one wants to leave that solder connection intact. The potting compound will help hold everything in place, including the solder, but...just to be on the safe side, don't take all day about attaching the wires. The potting compound might soften and let the solder leak away where you can't see the damage. ;)
     
  12. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    I think the OP wants to maintain the connector as a connector, whether with a multi-terminal socket or individual female terminals. The solder method has merit only if it's going to be a one time job and then scrapped at the next system failure.
     
  13. tom_s

    Member

    Jun 27, 2014
    285
    333
    if soldering were to be done, you'd need an iron with a decent amount of wattage as the process needs to be done quickly (60/80w temp controlled)

    and terminal blocks connected just incase it needed to be inspected at a later date.

    also not forgetting to heatshrink the spade terminals
     
    strantor likes this.
  14. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    Why do you say that?
    I didn't see him indicate that he wanted anything other than a more secure connection, which I don't think can be achieved by anything but direct soldering.

    Why do you say that?
    If it can be soldered once, it can be desoldered and resoldered again.
    Perhaps if removal & reinstallation really is a priority, he can solder on 2-3" leads with ring lugs on them and bolt the mating wires together. Or use something like this:[​IMG]
    [​IMG]
     
  15. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    Because the OP, in his post, asked for "high quality female connectors".
     
  16. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    True. I've never seen one though.
     
    #12 likes this.
  17. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    The differences in quality between the good industrial versions and the consumer versions is significant. In a nutshell, the industrial connectors are made with metal of a specified alloy and thickness which is heat treated after bending while the consumer versions are just punched and stamped from thin plated brass or copper, assembled and packaged. Because they're relatively soft and thin, the consumer connectors are easier to crimp and connect but this also means they have less holding force in both areas.
     
  18. #12

    Expert

    Nov 30, 2010
    16,284
    6,797
    Please post some link or reference for those of us that failed to find them so far.
     
  19. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
    #12 likes this.
  20. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    I've used the (severely) overpriced chinese junk spade terminals sold in "kits" in autozone, and I've used the nice industrial Thomas & Betts spade terminals, and neither of them gave me sufficient confidence. I can't say that I recall ever seeing one of the nice ones fail, but they still just don't "feel" like a solid connection to me. When in doubt, solder... and I'm always in doubt.
     
    #12 likes this.
Loading...