How to Choose the Right Solar Inverter? MPPT vs PWM Explained

Having a solar system is a smart means of saving the environment and money. But in order to effectively use your solar system you require the right solar inverter. Your inverter transforms the electricity generated by your solar panels into usable power within your household. Using the wrong inverter can lead to inefficient performance and wasted resources. Two of the most popular charge controllers for inverters are MPPT and PWM. In this blog post, we'll describe both and assist you in selecting the most suitable choice for your requirements.

What is a Solar Inverter?

Let's first learn about what a solar inverter is. Solar panels generate electricity in the form of DC. But homes and appliances use alternating current (AC) most of the time. A solar inverter converts DC to AC so that your home can use the electricity of the sun.

Solar inverters also possess a charge controller in off-grid solar systems and hybrid setups. The charge controller controls the charging of electricity into the battery. One of the two simplest forms of charge controllers is:

• Pulse Width Modulation

• Maximum Power Point Tracking

Both are doing the same simple thing but in different ways and produce different results.

What is PWM?

PWM is the conventional and simpler form of charge controller. It powers the battery directly through the solar panels. If the battery reaches a certain voltage, the controller lowers the flow of power so that the battery is not overcharged.

Benefits of PWM:

• Less costly

• Simple to install

• Best suited for small systems

Operation:

PWM charge controllers reduce the panel voltage to equal the battery voltage. This wastes some energy as the additional voltage from the panel is not utilized to the maximum.

For instance if your panel produces 18 volts and your battery requires only 12 volts the additional 6 volts are wasted in the process. This results in lower efficiency.

What is MPPT?

MPPT is a new and more efficient technology. MPPT stands for Maximum Power Point Tracking. It regulates the voltage from the solar panels to obtain the maximum power possible regardless of the weather or time of day.

Characteristics of MPPT:

• Improved efficiency (up to 30% more efficient than PWM)

• Operating efficiently in cloudy and cold conditions

• Best suited for large systems

• Very slightly higher price

How it works

MPPT controllers track the best voltage and current point through which the solar panel works most efficiently. It then delivers that power according to the battery need. That wastes no power and the battery is charged efficiently and quickly.

MPPT vs PWM: Key Differences

The following is a simple comparison to provide you with an idea about the key differences.

Efficiency: MPPT is more effective than PWM especially if sunlight is weak or the temperature is low.

System Size: PWM is effective for small systems with low power demand. MPPT is better suited for large systems with higher power demands.

Cost: PWM is cheaper but less powerful. MPPT is costlier but yields more output.

Technology: PWM uses simple switching. MPPT uses smart tracking and can handle voltage fluctuation better.

Battery Charging: MPPT charges batteries faster and more efficiently especially when panels produce extra voltage. 

Which One to Choose?

Choose between MPPT or PWM depending on your needs, budget, and solar system size. These are some recommendations:

Choose PWM if:

• You have a small solar system

• You're working with a tight budget

• You live in an area with strong and stable sun

• Your solar panel voltage is close to your battery voltage

Choose MPPT if:

• You have a medium-sized to large solar system

• You want better performance in different weather

• You want to be able to use higher-voltage solar panels

• You live in areas that have changing sunlight and temperature

Why Quality Matters

Whatever you choose, buy a good quality inverter. A cheap or bad quality inverter will cut down the life of your battery and use a lot of energy. Poor inverters may also fail at times when you want them to work. For this reason, our products at Microtek are employed by thousands of people across India. We offer efficient and long-lasting inverters that cater to everyone's demands and needs.

Final Thoughts

A solar inverter is the brain of your solar system. Taking the right decision is important for energy saving, optimal performance, and uninterrupted power to your home without any problem. PWM suits simple needs, but MPPT is more efficient and suited for changing conditions. If even then you are not sure, then it is always advisable to seek advice from the experts before choosing any one of them.