What Is a Solar and Wind Power Charge Controller?

What Are Charge Controllers?

Charge controllers are designed to prevent your batteries from being overcharged. They do so by limiting the amount and rate of charge delivered to your battery. Charge controllers also work to avoid battery drainage by shutting down the system when the stored power falls below 50 percent capacity. 

Solar and wind-powered charge controllers also charge the battery at the correct voltage, which preserves the life and health of the batteries. 

If you are considering installing an off-grid solar project, consider looking into a charge controller for your system. These systems have batteries attached to them, and charge controllers act as a gateway to your battery. They ensure you are not misusing and overcharging the battery, as it can damage your energy storage system. 

You only need a charge controller in some cases. You may need one if you are trying to install an off-grid solar system on your roof or boats and RVs. On the other hand, installing a solar system with a battery connected to an electric grid does not need a charge controller. When attached to an electric grid, the battery directs the excess energy to the grid. By doing so, you avoid overloading the battery and prevent it from getting damaged.

How Do Charge Controllers Work?

Diagram explaining how solar charge controllers work.

A solar charge controller works by being connected between the solar panel and the battery. This setup ensures that the power from the panel goes through the charge collector and safely and effectively reaches the battery. 

The battery feeds into an inverter responsible for changing DC power into AC. This inverter or battery is used to run appliances, which are also called loads.

Charge controllers have four main functions. These include accepting incoming power from solar panels, controlling the amount of power sent to the battery, and monitoring the battery’s voltage to prevent overcharging. They also allow power to flow from the solar panels to the battery to avoid power losses. 

Charge controllers work to limit the voltage as voltage increases while the battery is charging can damage it. They ensure the battery receives sufficient power to charge it but not too much. It does so by reading the battery’s voltage and calculating how much additional energy would be needed to charge it fully. 

Another essential function of charge controllers is ensuring that the current does not travel back to the solar panel. When the sun is not shining, the lack of voltage production may cause electricity to flow backward, as electricity always travels from high to low voltage. 

If electricity travels backward, it can potentially damage the battery, and you may end up with a dead battery sooner than you anticipated. A charge controller has a diode that only allows energy to flow in one direction and prevents electricity from feeding back into the panels.

When the battery needs to be charged, the solar panels must have a little higher voltage than the battery it will be charging. This helps ensure that the voltage only flows from the panels to the battery and not backward. Most solar panels are designed to take this into account and put out more voltage than the battery at all times. 

Who Needs a Solar Power Charge Controller?

Worker installing a solar panel.

You need to have a charge controller connected to a battery when it is connected to DC or direct current outputs of solar panels. Usually, these are in the form of small off-grid setups like the ones you might have seen on RVs and cabins. 

Some charge controllers are also designed to provide battery backup for existing grid-tied solar systems in homes or businesses. In such cases, you require a high-voltage charge controller. You may also need to rewire the system to direct the solar output to the charge controller. 

Types of Solar Power Charge Controllers 

There are two kinds of solar-powered charge controllers if you want an off-grid solar system. If you are in the market to purchase a solar power charge controller, then consider which one will serve you best. 

Feature MPPT controllers  PWM controllers
System Size Grid-tier system with variable voltage. Off-grid with 12V
Climate All Warmer climates
System Type 170 W or larger Variable
Budget $28 to 324 $15 to $125
Maximum Power Point Tracking Charge Controllers

MPPT solar charge controllers are also called Maximum Power Point Tracking solar charge controllers. They are the more expensive of the two and have a complex charge control option. These charge controllers offer you the exact switch-like protection that PWM controllers do and will also reduce the power that flows to your home battery. It will only reduce the power when it is nearing its full capacity to prevent it from being damaged. 

MPPT charge controllers can pair non-matching voltages from panels and batteries. Something that PWM controllers can’t do. These controllers also adjust their input to bring in the maximum possible power from your solar panels and vary their output to match the attached battery. 

This feature makes MPPT controllers much more efficient than PWM controllers. They can also effectively utilize the full power of your solar thermal energy panel to charge a home battery.

Pulse Width Modulation Charge Controllers.

PWM solar charge controllers or Pulse Width Modulation Charge Controllers are the standard types of charge controllers available on the market. They are less expensive and much more straightforward than MPPT controllers. 

PWM charge controllers work by slowly reducing the amount of power that goes into your battery as it approaches its full capacity. When your battery is fully charged, PWM charge controllers maintain a steady trickle of power. This means that they supply a minimal amount of energy to ensure that the battery remains full. 

To be able to use a PWM charge controller, you need to ensure that your home battery and solar panel system have matching voltages. This may not be the case if the solar panel is large and designed to power your entire home. Due to this reason, they are primarily used in small DIY solar systems with a small battery and a few low-voltage panels. 

What To Consider When Purchasing Solar Power Charge Controllers

Workers working among solar panels.

If you are in the market for a new charge controller, there are a few features you need to keep in mind to ensure you are purchasing one that fits your needs best.

The Kind of Panels You Have

The first factor you need to consider is the kind of panel you have. Most off-grid solar panels are 36-cell panels, and these can usually charge a 12V battery. Such small systems work great with PWM charge controllers that require the voltage of the battery and the panels to be the same. 

Other kinds of solar systems are larger and have 60 to 72 cells. These are usually used with grid-tie solar panel systems with high voltages. For such setups, a larger MPPT controller is needed. 

The Size of Your System

The size of your solar system also plays an essential role in the charge controller you buy. If you have a large setup, it is likely that the voltage of the battery will not match that of the solar system. Due to this mismatch, you cannot use smaller PWM charge controllers; instead, you will have to opt for MPPT controllers. 

You should also check the voltage before you make your decision because MPPT controllers are less efficient if your setup has less than 170W.

The Temperature You Expect

The climate you live in also plays a huge role in the type of controller you should purchase. Suppose you live in a relatively colder region. In that case, you should opt for an MPPT controller because they work better than PWM controllers.

The drop in temperature often causes an increase in voltage which PWM controllers cannot handle. MPPT controllers can capture them efficiently and are the better choice in such a situation. 

If you live in a warmer climate, there is no extra voltage to deal with, making PWM charge controllers the perfect option. Provided that it is a small setup with matching voltages between the panels and the battery.

Your Budget.

The kind of solar or wind power charge controller you purchase depends mainly on the amount you are willing to spend. Generally, MPPT controllers are more expensive than PWM controllers, and this difference is primarily due to the difference in efficiencies. An MPPT controller is designed to offer 20% higher efficiency than PWM controllers. 

The extra cost of the MPPT controllers is also due to their four-stage charging method that protects your battery and ensures that it lasts long. This is not to say that PWM is the lesser charge controller because they have their own advantages. Although they are cheaper, they are much more versatile and easy to install. 

What To Consider When Purchasing Wind Power Charge Controllers

Closeup of wind turbines.

When purchasing wind power charge controllers, you must choose one that perfectly matches your system in two aspects. These two aspects are capability and maximum size. Other factors you need to consider are whether it supports your battery bank type and your battery bank voltage.

You should also consider the input power type and the maximum power capability in watts. The maximum power should meet or exceed the wind turbine’s capabilities. 

Common Mistakes When Using a Charge Controller

Solar-powered systems have a lot of different components, which often increase the chances of error. The most common mistake made when using charge controllers includes connecting the AC load to the charge controller. Ensure that you only connect DC loads to the charge controller’s output. 

You should also only attach low-voltage appliances directly to the battery.

Another mistake many people make is mounting the charge controller far from the battery. Ensure that they are close together since the measurement of the battery’s voltage is vital for the function of solar charge controllers.

Pros and Cons of MPPT and PWM Controllers

Solar panel on a building top.

Although both MPPT and PWM are designed to be used in different situations, you may need to choose between the two. Here are some pros and cons to make the decision easier. 

MPPT controllers Pros PWM controllers Pros
They offer an increase in charging efficiency by up to 30%. They are extremely inexpensive.
You can have an array of higher input voltage as compared to battery banks. They are available in various sizes of up to 60 amps.
You can purchase various sizes of up to 80 amps. They are extremely durable and have a passive heat sink style and cooling. 
Their warranties are longer. Their various sizes enable them to be used for many applications.
They offer flexibility and an option for system growth.

There are also some cons of both types that you should be aware of.

MPPT Cons PWM Cons
They are expensive and can cost almost twice as much as AWM controllers. The voltage of the battery and the panels should match.
They are larger in size. There are no controllers over 60 amps.
MPPT charge controllers can force the PV array to be compromised. They offer limited capacity for growth.


Once you know the kind of controller you want, you must purchase one from a reputable brand. These brands use the latest technology to craft their products, meaning they are the best in the industry.


Renogy’s power charge controllers are designed to be DIY-friendly and have options that can be used for all kinds of off-grid projects, no matter their size. They offer a large variety of inverters, charge controllers, panels, and even batteries. Most charge controllers under this brand are perfect for smaller projects. If you need a controller of any size, Renogy will probably have it. Popular controllers from the brand include the Renogy Wanderer.


If you are searching for a reliable power charge controller, BourgeRV’s controllers are the best in the market. They are incredibly reliable and perfect for those in search of off-grid solutions. They have PWM and MPPT chargers and various sizes and compatibility options to choose from. Some popular models from the brand include the BougeRV MPPT Charge Controller and the BougeRV PWM Charge Controller.

Victron Energy

Victron Energy offers the widest range of off-grid energy supplies. The company has been a staple in the industry for ages and manages to produce products based on its customer’s needs. You will be able to find a large variety of different charge controllers under this brand. Some popular models include the Victron Energy BlueSolar PWM and the Victron Energy BlueSolar MPPT.


How do I choose a charge controller for my wind turbine?

To choose a charge controller for your turbine, you must ensure a few things. These include that the one you choose has the maximum input power type, supports your battery’s voltage and type, and has the maximum power capabilities. 

What happens if the charge controller is too big?

If you choose a charge controller that is too big, the power will be wasted as the controller will always limit the output. 

Can I connect two solar panels to the same charge controller?

Yes, you can connect two solar panels to the same charge controller, provided that you attach them in parallel. Your battery management system should also be able to handle the maximum input power.


Solar and wind chargers are put in place to protect your batteries from receiving excessive amounts of voltage and getting damaged. They are extremely useful, provided that you select the correct one. Many considerations go into choosing the perfect power charge controller. Still, if you keep specific considerations in mind, you will be able to choose one that fits your needs best.