What is The Maximum Cable Length for Solar Panels?

Last Updated: June 26, 2022

A question that mostly arises when picking a solar power system for your use is its cable length size adequacy. The question can be precisely presented as, ‘How to ensure minimal energy loss between the battery and panel?’ The reason to get a solar panel in the first place is to get the most out of them with a satisfactory setup. This article covers the maximum cable length for solar panels for your setup.

The ideal distance between batteries and solar panels is 20 – 30 ft. the lesser the distance, the better the output. When the cables are thin and long, there is a high amount of energy loss by the resistance of flow from the conductor. However, a thicker and shorter cable minimizes energy loss amidst transmission.

1. Panel to Battery Distance

The ideal distance between panels in an array and backup of a solar battery is 20 – 30 ft. If the wire distance from the battery to the panel is long, the transport will result in high energy loss. The amount of energy lost is dependent on the wire gauge or thickness. Thin wires tend to lose more power, and thick wires lose energy more.

Solar Panel Charging

When you look for a charger for a single solar panel, what is the ideal size for the cable – long or short?

Since it was mentioned above that short cords result in less energy loss, the case with mobile solar panels is different. With them, the wires are of higher gauge due to a thinner overall structure. If you opt for a short cord, more power will be supplied from the panel to the battery, which makes the placement of the panel inconvenient. Putting it directly in sunlight gets difficult while trying to connect it with the device in use.

Best Wire Gauge

If the panel is over 50 watts in a home array, then ten gauges are the ideal limit for a cable. However, if the panels are above 50 watts and attached in a string, the wire gauge depends on the length. Short strings require an 8-gauge wire, and longer strings need wires of 3 gauge.

When multiple solar panels are connected in parallel, they are considered a string. The driving force of the energy through the panels becomes a single unit of power eventually. The supply from a 10-gauge wire is mostly 30 amps; the more the panels added, the higher the amps will go. This indicates why a thicker wire is ideal in such circumstances.

It can be extracted till now that a small number of gauges show the wire is thicker. Therefore, a 3-gauge wire is thicker than an 8-gauge wire.

2. Power Loss

The loss of power occurs naturally. It can be seen when energy is transmitted along the wires. More power is lost as far as the energy keeps traversing. In the public utility grid, when the energy is transmitted through high-voltage lines, around 2% of the energy is lost.

The same loss of energy is expected when energy travels from the panels to the inverter, batteries, controller, and appliances. The power loss emphasizes the need to keep components and panels close.

3. Inverter to Panel Distance

Putting the inverter at the right distance from the solar array is crucial. However, figuring out the distance can require two-fold explanations. Firstly, it will depend on the backup system for the solar panel as it revolves around the distance of batteries from the inverter.

Secondly, solar batteries work on DC Volts. However, the solar panels produce a voltage in DC currents. Therefore, it is safe to assume that there will not be a need for inverters to be in between panels and batteries as both consume current in DC volts.

Now, what is the ideal distance of the panel from the inverter? Even though there is no exact distance required for their placement, they shouldn’t be further than a yard from each other. The batteries and the inverter should lie in the same parameter. In some cases, the home is grid-tied. So, the inverter can be mounted near the meter box.

4. Solar Component Distance

If you have to design a solar array, you will need to measure the distance between the solar components, which include the inverter, appliances, panels, and controller. The simplest possible answer is to keep all of them in close proximity – approximately 30 feet for battery and array and a yard for battery and controller.

To ensure the power supply by panels is not limited, the controller must not be equidistant from the panels as it is from the batteries. It is because there will be a natural power loss in the system. The controller receives a lot of power from the panels, which in turn blocks the flow, so batteries stay protected.

This shows that loss of energy in the process is predicted. However, it is very detrimental if the loss between the battery and controller is high. The batteries and inverter must be a yard away from each other. Lastly, the devices and inverter should be placed in a manner that takes the shortest distance to reach the electric box.

5. Does Solar Power Require an Inverter?

The answer is not always. Certain devices run on DC. If the run of solar energy is from the panel to the battery, then you may not require an inverter. However, if solar power provides energy to devices running on AC, then an inverter is required.

If DC is sent directly to home appliances, the chances are that it will wreck the electronics and appliances. This results in overheating of these items and causing a fire. So it is short and simple; a DC to AC circuit will always need an inverter.

6. Running Solar Panels

When seen in the perspective of the panel to building distance, the max is below 500 ft. If the user is any farther than that, then the array will be much more expensive. But, for a heavier wire gauge, more conduit piping and troughing will be required to fit both.

7. Appliance to Panel Distance

Ideally, the panels are installed on the roof of any building. This location advantages the placement of batteries, inverter, and controlled in proximity. Any line that extends more than 20 to 30 ft for the solar components to the panels is discouraged. It can be a battery system or a controller, or both.

8. Panel to Panel Distance

The sizes of panels can vary vigorously, but most are not as big as they seem. The ideal sizing is 55.4 inches in height and 35.6 inches in width. When the panels are installed, the manufacturers provide these readings rounded to the nearest inch, so there is a high chance of finding 36 x 56 on their packaging.

The ideal space between the panels is an inch from the manufacturer’s packaging value. This will provide the added space to ensure easy access. People want to fit the panels in the shortest possible distance; an inch is all that you will need to compromise for that.


The above discussion summed up the need for panel cables to be as ideal as the panel itself. Even though a cable is a small component of the panels, many will not notice its importance. However, cable size between the components and across the supplied appliances matters a lot. These determine the chance of power loss and energy loss. Therefore, the maximum cable length for solar panels should be kept between 20 to 30 feet.

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