One online source says the current capacity for an EC5 is “capable of more than 120A continuous current with 10-awg wire.” I don’t know what the manufacturer says. I’ve drawn more than 50A through an EC5 flying drones with no problem. The cross sectional area of the connector appears to be as much as a 10awg wire. In any case, I don’t plan to draw more than 20A through them for ham radio.
I assume there is some RF noise (haven’t checked), but only during charging. The charging circuit isn’t used when discharging from the 12v port.