Quote:
Originally Posted by Al Skierkiewicz
Guys,
I would need to see the actual tested ratings for these connectors. None appeared in the link above. Although the 35 amp Power Poles would seem a bad choice remember the Power Poles are rated for continuous duty at that current. Have you noticed that the battery is only a 50 amp Power Pole? The two minute (say up to ten minute) rating for these connectors far exceeds the failure point of 35 amps continuous. In case you haven't tried, Power poles are easy to solder but if you use the West Mountain crimper, with #10 wire your connector resistance is already very low. If you solder, it is almost the same resistance as a wire. A bad crimp on any connector (or a solder job that only covers part of the wire) will get hot under load. Inspectors need to have numbers. You may have been able to get away with them in the past but if they are under rated, then you will need to change.
As stated earlier, I recommend using the least number of connections you can. We use Power Poles on motors (and in special applications) only to allow their rapid removal. Everything else is point to point.
For reference...
CIM Stall Current is 129 amps
Fisher Price Stall Current is 70 amps
Battery (charged) is capable of over 600 amps.
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Al,
For reference, I find that quite often, published specs are misleading, and in some cases outright wrong. I did a great deal of research with the CIM motor over the last year (not FIRST related). While the data around the higher efficiency end of the curve is reasonably accurate, as you get farther from that point, it goes off into the weeds. Using accurate instrumentation, I measured the current at several different operating speeds and loads. I was using a 95 AH AGM 12V battery with an internal resistance much lower than the FIRST batteries. I don't remember exactly how high the current got at its highest, but it was very near 30 Amps, no more than 35. That was when the motor was nearly stalled. At stall, the draw dropped to less than 30 amps. Not sure why the data sheet says what it does, but the CIM doesn't draw 129 amps.
Based on that, and the fact that Fisher Price toy cars (the main use of the FP motors) are wired with ~14 gauge wire, I don't believe the 70 amp rating on them. I know my kids were able to stall the motors out on the jeep they drove around, and no wires smoked.