What guage wire do you use for 40A circuits

[Al Skierkiewicz]

Expanding on Richard's post above, I like to the use the analogy of the "Wire Foot". This is an easy way to calculate out losses on the robot. The Chalupa and FP motors have stall currents near 100 amps. #10 wire has about .001 ohm per foot, which at 100 amps drops .1 volts. Add up the length of wire (both sides, black and red, please) and you can easily see how much drop you will encounter for your design. A few fudge numbers for you as well...one foot of #6=.5 wire feet, #12=2WF, Victor=2WF, battery internal resistance=11WF. Good connections should have very little resistance but bad crimps and loose hardware can account for as much as 1 or 2 WF per connection. Add in 1WF for breakers (total) just to be on the safe side. Once you have made the simple calculation then compare it to the motor graph for your motor. If you cannot supply a full 12 volts then the preformance of your motor slides down the graph to a lower performance area of the graph. If you had designed for peak torque, addig 6 ft. of #12 will not allow you to achieve your design goals.