Polarity Convention:
- + is the male pin on the battery.
- - is the female pin on the battery.
- + on the speed controller is the female pin (battery side)
- - on the speed controller is the male pin (battery side)
Color Convention:
- Red on batteries
- Black on ESC/charger
- Black plugs harder to get, a lot of people color them with sharpies.
Youtube overview and soldering guide.