Volts * current = watts.Okay, again my ignorance is at work, but I thought my cables just carry Watts.
Weather temps here 'bouts will drop to -20F. Not often, but -10F a least once a winter (Colo Rockies). My system is to support RV boondocking, and I try not to be out in -10F.
Yes, as well as current, your cable carries watts. Increase the voltage and you increase the watts. However in this instance, you have a hard limit of how much the voltage can increase before you kill your solar charge controller.