Solar Controller Negative vs Positive Ground

Solar Controller Negative vs Positive Ground

Solar power is the most affordable and environment-friendly way to produce energy. You can produce solar energy from the sun, which is free and also helps in keeping your surroundings green.

If you are interested in harnessing the sun’s energy for your home, you should consider getting a solar system.

From rooftop solar panels to smaller portable devices, there is a variety of converting devices available on the market today. One such device is solar controller.

When it comes to solar controllers, there are two concepts, positive and negative grounding.

What is a solar controller and how does it work?

A solar charge controller (CC) is a vital part of any solar system. It’s a vital part because it regulates the charging of your battery bank from the solar panels. The role of a charge controller is to ensure that your batteries don’t get overcharged or undercharged, which can damage them.

Off-grid solar systems are electrically powered circuits that can cause damage to human bodies, and to avoid damage to the PV system from lightning strikes, an grounding system is required for protection.

There are two types of solar controller, mppt controllers and pwm controllers, both of which involve the concept of grounding.

Understanding Negative and Positive Ground Solar Controllers

A negative ground solar controller is a special type of solar controller that is used to provide power to a battery bank connected to the solar system on a negative terminal.

When using a negative ground solar controller, the negative terminal of the battery will be connected internally and have an equal electrical potential with the positive terminal of the solar controller.

The neg ground controller is mainly used in applications such as RV and boats where the metal part of the body is used as the negative circuit.

Advantages of Negative Ground Solar Controllers

A negative ground solar controller has the positive line as the “hot” line, which carries the +12 or +24 volt potential. The negative line is also referred to as ground or return, which is used to carry back-voltage and ground current.

A positive ground charge controller is not recommended for solar PV systems that have the battery negative connected to the chassis.

This is because positive ground charges damage the batteries’ internal chemistry and can cause permanent damage.

A negative ground controller prevents this by taking the positive terminal of the solar panels and inverting it with its own negative terminal.

This effectively creates a battery in series with the solar panels, and negative ground controllers are capable of handling battery charging just as well as positive ground system controllers.

Additionally, negative ground solar controllers are more environmentally friendly since they don’t require a connection to an external power source or a connection to the grid to operate.

Advantages of Positive Ground Solar Controllers

Positive ground solar controllers are beneficial in that they prevent the Low Voltage Disconnect and Electronic Fuse functions from being short-circuited.

In contrast to negative ground systems, positive ground solar controllers provide a stable +12 or +24 volts potential for the solar system.

This helps to protect your system from damage caused by fluctuations in voltage.

Furthermore, positive ground systems have a more reliable connection with the solar panel and have a lower chance of disconnecting due to external factors.

They are also able to provide a negative voltage of -48 volts which is used as the return or common wire.

This prevents damaged solar panels from causing further harm to your system.

Additionally, positive ground solar controllers can be used in vehicles which have the battery negative on the chassis.

Deciding Between Negative and Positive Ground Solar Controllers

When using solar power, it is important to consider the type of solar controller used. Solar controllers are electronic devices that monitor and regulate the output of a solar system. They can be positive- or negative-grounded, depending on the configuration chosen.

Negative-ground systems supply +48 volts with the negative line grounded and used as the return or common.

Positive-ground systems use +12 or +24 volts as input and output voltages.

This inconsistency makes it difficult for solar controller manufacturers to provide a recommendation for each type of system.

Frequently Asked Questions

What is a solar controller negative ground?

A solar controller negative ground refers to a wireless communication site or network device that is typically powered by 12, 24, or 48 volts DC and operates with a negative ground configuration. This means that the negative line is used as the ground or return, and the positive line is the “hot” line that carries the +12 or +24 Volt potential.

For a vehicle, the negative ground system is used, meaning the MPPT Solar Charge Controller must also be negative grounded.

What is a solar controller positive ground?

A solar controller positive ground is a type of DC power supply system in which the negative line is used as the ground. This means that when the solar controller is plugged into the car battery, the solar controller’s negative terminal (the one closest to the ground) is connected to the car body, also known as the return or common.

This way, if there is an issue with the battery (for example, it’s low on charge), the solar controller’s Low Voltage Disconnect and Electronic Fuse function will protect the controller and any connected electronics from being damaged.

Are solar panels positive or negative ground?

Solar panels are typically paired with a positive-ground capable charge controller. A positive ground controller ensures that the solar panels will connect to the battery and begin to charge it. The polarity of 12 and 24 volt devices is typically either +12 volts DC or +24 volts DC, also known as negative ground. For 48-volt sites, these typically operate with a positive-ground configuration, or occasionally with a negative-ground configuration.

All vehicles have a NEGATIVE ground system, so when choosing a solar charge controller, remember to choose a negative ground charge controller.

Why use a positive ground charge controller?

Positive ground controllers (Low Side Switched Controllers, or LSSC) are used to incorporate a camper’s electrical system into the vehicle. This prevents any communications i/o (like ethernet or other jacks) from connecting to devices that are grounded to the vehicle.

Additionally, positive ground controllers can be used for Wireless communications sites and network devices operating on 12, 24 or 48 volts DC. Positive ground systems supply the negative line as the ground, return or common, and the positive line as the “hot” line which carries the +12 or +24 volt potential.

Does my charge controller need to be grounded?

Yes, it is important to make sure that the charge controller you are purchasing is grounded. This is because charge controllers are used to regulate the charging of a battery bank from solar panels.

If your charge controller is not grounded, then it may not be able to properly control the charging process and damage may be done to the batteries. Therefore, make sure to do your research and purchase a charge controller that is specifically designed for your solar panel setup.

Once you have purchased the charge controller, it is important to install it correctly. Make sure to double-check that the ground connection is secure and that the voltage is correct before turning on your solar system. If you have any questions about installing or using a charge controller, please don’t hesitate to reach out to a professional for help.

Grounding my batteries/inverter?

When grounding your batteries, it is important to understand the configuration of the battery system. In a positive-ground system, the positive (+) line of the battery should be referenced to ground. In a negative-ground system, the negative (–) line should be referenced to ground.

If grounding is required, always connect the positive wire. If the device is used in a vehicle with battery negative on the chassis, loads connected to the regulator must not have an electric connection to the car body.


There are a lot of solar controllers in the market today. And they are all different. It is up to you to decide which one suits your needs best. In this blog, we looked at how negative and positive ground solar controllers work, their advantages and disadvantages, and where you can get them.

We hope it has helped you understand the basics of these solar controllers a bit better. Remember, if you have any further questions, feel free to comment below. We’re here to help!

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