It is very important to choose a suitable cable diameter for the controller. Generally, at least ensure that the voltage drop of the cable from the controller to the solar panel, the controller to the battery, and the controller to the load is less than 2% of the system voltage.
The following table 3-2 provides the minimum wire diameter requirements at an ambient temperature of 45 degrees Celsius:
Model | Recommended Size | Minimum Size | ||
20A | Copper | 10AWG | 12AWG | |
30A | Copper | 10AWG | 12AWG | |
40A | Copper | 6AWG | 8AWG | |
50A | Copper | 5AWG | 6AWG | |
60A | Copper | 5AWG | 6AWG | |
70A | Copper | 4AWG | 5AWG | |
80A | Copper | 4AWG | 5AWG |