[time-nuts] DC distribution

[John Miles]

> In the case of Power-Pole connectors, as someone else described, the
> exact placement and alignment of the crimp, and how the terminal deforms
> during the crimp, is important to successful insertion of the crimped
> terminal into the plastic shell where the contact-force leaf spring
> retains the terminal and actually supplies the contact force. That's why
> Power-Pole crimp tools position and align the contact end of the
> terminal for crimping.

The deformation of the terminal is a bigger deal than it appears at first.  It is what gives the leaf spring room to do its thing.  These are designed under the assumption that the contact will flatten out when crimped, and soldering by itself won't do that.  

Longer story: I always used to solder PowerPole connectors, being too lazy to hunt down a crimper for them.  (Until recently, I also wasn't aware that a good crimper could be had for $30 rather than $300.)  Awhile back, I somehow managed to build a mated pair of 30A connectors that was completely open unless it was flexed in a particular direction.  An X-ray of that one really drives home the point that Larry makes about deformation:

http://www.ke5fx.com/PowerPole_soldered_15sec_25kVp.png

Compare to properly-crimped terminals:

http://www.ke5fx.com/PowerPole_crimped_15sec_25kVp.png

My defective pair of 30A connectors yielded nice 'clicks' when I assembled them, as usual, but they don't snap together as nicely when mating.  Because the soldered contacts are physically larger than the ones that come out of the crimping tool, the leaf spring can only do so much to compensate for bending forces.  The contacts need more room to move.

Originally I thought the escaped solder from the front of the crimp area was what was distorting the contact geometry.  It is probably what made the difference between the failed connection here and plenty of 'good' ones I've also made.  But when I looked at the X-ray of the crimped version, I realized that the shape of the terminal was the real issue.   There is arguably no way to do this job right without crimping.

-- john, KE5FX
Miles Design LLC / Jackson Labs LLC