Solar cables and connectors provide a solid and solid connection between the solar panel and the controller, and between the controller and the battery.
The solar connector is designed for counter-coupling the panel. Each solar panel has a pair of MC4 connectors already attached to the purchase. To connect from the panel to the controller, you need another pair of MC4 connectors (shown below):
Solar cables have a cross section of 4mm2 or 6mm2. Each cable cross section has a RED cable (plus) and a black cable (minus).
Incorrect cable dimensioning and inadequate cable length can cause significant losses in the solar system as well as fire.