Cable dimensioning is a critical point!

What cable to choose?

Tri-rated cables


To connect the components of a solar energy system will need to properly size the cables to ensure low energy loss and to prevent overheating and possible damage or fire. Below is a graph which correlates the size of cable required and the length necessary to connect the solar panels to the charge controller.


minimal lead in mm2 (for a maximum of 5% of the voltage drop to 12V DC)
AmpsCable lenght in meters (one way)

These figures apply to the 12-volt systems in order to obtain a reduction of 5% or less of the voltage.

If you can not find the exact number, choose a higher gauge wire, or select a distance greater than its actual distance.


Cable for connecting solar panels to the charge controller 12 volt

The table shows distances and voltage drop of 5% or less and are calculated for a 12 volt system.

Multiply by 2 the distance for a 24-volts.

Multiply by four the distance for a system at 48 volts.

Connecting the charge regulator

After connecting the solar panels to the input terminals of the charge controller using the above table, you can use the same cable to connect the controller to the battery as it should not carry more current than the solar panel. In any case the distances are smaller as possible from the batteries.

Connecting the Power Inverter

During operation, the alternating current produced by the inverter consumes a high number of apm from the batteries. Not only the cables must be large that the distance is also necessary not to exceed 2 meters from the batteries. These cables as the cables of a battery for large cars. Use the maximum possible size. A unit of 10 amps of alternating current (such as a microwave oven) takes 100 amperes at 12 volts DC. Even the large wires will heat up. Do not save on this point.

Battery connection

Require large cables. The charging current and the current flowing through the battery bank will be the maximum. Connect the batteries with high quality cables.