PWM vs MPPT Solar Charge Controller

For RV owners, few components are more important than the solar charge controller they use in their systems. They perform a number of important functions to charge and protect RV batteries, and while there are several different types of controllers, there are two types that do the best job.

The two best types of solar charge controllers are Pulse-Width Modulated (PWM) and Maximum Power Point Tracking (MPPT). What follows is a breakdown of PWM vs MPPT, how they both work and what are some of the most important tradeoffs when using each one. 

Below we will also cover the best MPPT & PWM solar charge controllers in the market today.

What Do Solar Controllers Do? 

Solar controllers monitor the voltage being applied to a battery. They make sure the battery gets to a fully charged state as quickly as possible. They also prevent the battery from overcharging which prevents sulfation; the number one reason for early battery failure. Therefore, the solar controller helps extend your battery lifespan. 

When the battery is fully charged, the controller protects the battery by limiting the amount of current flow to the battery.

In most solar panel systems, the panels are sized by watts, but the solar charge controllers attached to them are sized by amps. The voltage and amps between the panels and the battery must be carefully matched in order for solar charge controllers to perform the charging properly.

The quality of the solar charge controller matters, too. One of the best ways to tell a well-made controller from a cheaper one is to look for UL certification or other labeled evidence that the device has undergone independent testing according to accepted standards.

Cheaply-made controllers often give off electrical noise that can interfere with TVs, devices and other electronics, and this level of certification and testing minimizes that possibility.

Also, there are a number of emerging features that are an important part of advancing solar charge controller technology. These include Bluetooth connectivity that makes it possible to monitor and control charging remotely, and these can be convenient for those who have the budget to afford them.

Pulse Width Modulation (PWM) Solar Controller 

PWM solar charge controllers are the standard charge controller for most RV solar panel applications. They work according to a basic battery charging procedure known as trickle charging.

Trickle charging works by slowly reducing the amount of power going into a battery as it approaches a fully-charged state, then maintains a "trickle" to keep the battery topped off and fully charged.

Maximum Power Point Tracking (MPPT) Solar Controller 

MPPT is a more complex and expensive way to perform charging. It works by using an algorithm incorporated to extract the maximum amount of power from the photovoltaic (PV) module for your RV battery. The voltage at which the PV module produces maximum power is called peak power voltage

The maximum power amount will vary under different conditions, e.g., the amount of solar radiation from sunlight, the ambient temperature, and the temperature of the solar cell itself.

MPPT works by checking the output of the Photovoltaic (PV) module, then comparing it to the battery voltage. It determines the best power point the PV module can produce to charge the battery, then converts the ideal voltage to supply the maximum amount of current to the battery.

Quick NOTE: PV panels convert thermal energy into electricity while solar panels convert solar radiation into heat.  

MPPT is most effective in cold, cloudy or hazy conditions, which is when PV modules tend to work best. It also works better when the battery state of charge is lower since the MPPT can then extract more current to charge the battery. 

Difference Between PWM Solar Controller and MPPT Solar Controller 

The size and arrangement of the solar panel system is important when it comes to what type of charging to use.

PWM controllers work best with 36-cell solar panels that are designed to charge a 12V battery, which is a typical design. MPPT controllers work better with 60- and 72-cell panels, which usually have a higher voltage.

Also, PWM systems are ideal for small setups. While MPPT can handle large systems but tends to be less efficient when used in larger applications. As mentioned earlier, MPPT controllers are also better at handling colder temperatures.

Budget and efficiency considerations matter, too. MPPT controllers are usually more expensive than PWM because they have a four-stage charging method that can help extend battery life. They can also handle different voltage levels across a wider array of solar panel numbers.

PWM controllers, meanwhile, are easier to install, but their overall lower efficiency is the reason for the lower prices.

Want to Buy a Solar Charge Controller? Check out our selection of the best MPPT & PWM Solar Charge Controllers for RV.

Best PWM Solar Charge Controllers

Renogy Voyager 20A 

Renogy Voyager 20A is designed to be used to charge two 12V batteries. This solar controller is waterproof, so you can use it in any weather conditions without worrying about anything. It is sturdy and highly reliable. It has a large LCD that will show all the information you need to know. It's usable with many batteries, including AGM, flooded, or gel. Below are its features:

  • 4-STAGE PWM Technology: The Voyager controller is equipped with advanced smart PWM technology with high charging efficiency.
  • IP67 Rated Waterproof
  • Multiple Protections: The Voyager controller has multiple intelligent protections against reverse polarity, over charge, short-circuit, reverse current, overload, and over discharge, keeping your battery fully protected.
  • Backlit LCD displaying system: shows accurate and timely information.

HUINE 20A is made to extend the lifespan of batteries and solar panels. This controller will allow you to connect your panels and batteries more efficiently. It provides peace of mind since you know that your battery is correctly charged. It is waterproof so that you can use it in all weather conditions. The product is made from premium components, making it ideal for use in harsh environments such as outdoors or traveling.

  • IP68 Rated Waterproof and great for outdoor use
  • It has short circuit protection, over charge protection, over discharge protection, reverse protection. Can extends battery life time.
  • Can automatically senses 12V or 24 Volt for your batteries, working mode of the solar charge regulator is 24 hours.
  • Three LED lights can help you to know solar charging status, battery level, and load status.
  • Easy to mount directly on the frame of the solar panel

Best MPPT Solar Charge Controllers

This is our favorite MPPT charge controller in the market today for your RV. This product can be used in RVs, boating, and off-grid solar power systems. It is designed to charge 12V, 24V, 36V, and 48V battery packs. The item is controllable through a smartphone and is also compatible with solar trainers and e-bike charging stations. It will allow you to track the amount of energy produced each day and adjust the charge voltage accordingly.

  • Automatically detects 12V or 24V DC system voltages. Compatible with various Deep Cycle battery options: Sealed, Gel, Flooded, and Lithium.
  • Innovative MPPT technology with high tracking efficiency up to 99% and peak conversion efficiency of 98%.
  • Electronic protection against reverse polarity, overcharging, over-discharging, overload, short-circuiting, and reverse current.
  • Independent LCD screen and multiple LED indicators for displaying system operation information, customizable parameters, and error codes.
  • Electronic protection against reverse polarity, overcharging, over-discharging, overload, short-circuiting, and reverse current.
  • Die-cast aluminum design allows for efficient heat dissipation.

It is highly efficient and has many features that will make your life easier. This fantastic product includes Bluetooth, an integrated MWC controller to store solar power, a three-step charge algorithm with max current control, and dual MPPT charge settings. The board comes with a built-in regulator, which ensures its safe operation of it. This item will allow you to maximize the lifespan of your batteries by adequately charging them. It is designed to work well in harsh environments.

  • Bluetooth Smart Built-In
  • 5 Year Warranty

The product is designed to protect your batteries and solar panels from overcharging. It has three automated charging modes: PWM, PPM, and MPPT. You will know how much energy you are producing without needing extra accessories. You can connect this device to 12V or 24V battery systems. The LCD is easy to read and will show all the information you need about your system.

  • Advanced Maximum Power Point Tracking (MPPT) technology, with efficiency no less than 99.5%
  • LCD display design, dynamically displaying tool's operating data and working condition
  • Available for PC monitoring and external display realizing real-time data checking and parameters setting
  • User programmable for battery types, load control etc.
  • Protection from Battery over discharge / Battery reverse polarity / Load overload

AIMS Power is waterproof, making it ideal for use in harsh weather conditions. It is also sturdy and highly reliable. It has a large LCD that will show all the information you need to know.

  • POWERFUL: The AIMS MPPT charge controller uses an efficient algorithm to fully adjust with weather conditions to ensure that maximum power is harvested from the solar panel array throughout the day.
  • STACKABLE: Stack up to 10 of the same AMP rated AIMS MPPT solar charge controller together to maximize your solar array.
  • CHARGING: 4 stage charging at 12, 24, 36, or 48 Volt DC for 8 different types of batteries including lithium and a user defined option with adjustable voltage.
  • SAFE: Thermal design rugged case, Marine coated, Protections include: overload, short circuit, high voltage, high temperature, low voltage and auto correct
  • CERTIFIED: CE, ETL to UL1471 and RoHS compliant

Top solar is one of the most trusted brands in solar electronics. This solar charge controller is designed to provide your solar panels with the power they need to generate the electricity you need. It is suitable for both single and multi-step charging. It has three automatic modes that include PWM, PPM, and MPPT. The product will give you peace of mind by monitoring its performance regularly.

  • Features advanced MPPT technology with 99% efficiency
  • Complete system performance with a maximum conversion efficiency of 97%
  • Automatic detection of 12V or 24V DC system voltage.
  • Works with all popular battery types such as GEL, SEL, Flooded, AGM, and Lithium.
  • Die-cast aluminum design allows for efficient heat dissipation.

The product is designed to protect your batteries from overcharging. It comes with three charging modes: PWM, PPM, and MPPT. You can connect this device to 12V or 24V battery systems. The LCD is easy to read and will show all the information you need about your system.

  • Display real-time power generation and current.
  • Display fault records, to facilitate customer troubleshooting in a timely manner.
  • Battery temperature sensor (BTS) automatically provides temperature compensation.
  • The latest MPPT algorithm is used to track the maximum power point of solar power generation in real time. The charging efficiency is over 98.5 % and the tracking accuracy is over 99.73 %.