15：The Big Differences Solar Charger Between PWM and MPPT Controller

1. Different 12 Volt Solar Charger Charging Efficiencies

The charging efficiency of PWM controller is only about 70%. The charging efficiency of MPPT controller can reach over 95%. For example, charging the 1 kW solar panel,the PWM controller can only generate the maximum power output per hour is 0.7kW·h, and the MPPT controller can generate power up to 0.95kW·h.

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MPPT Solar Controller VS PWM Solar Controller

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2.Tracking Function

The solar panel maximum power generation efficiency changes by temperature.MPPT controller has the automatic tracking function which can automatically track solar panels maximum power generation efficiency. Thereby improving the efficiency of power generation conversion rate.

MPPT can automatically adjust the voltage and current to the maximum transmission power for charging. Thus it can achieve maximum charging efficiency.Such as the solar panel output power is 1000W, the output voltage is 48V, the output current is 20.8A. If the solar panel power is reduced to 500W, MPPT controller will automatically adjust the voltage below 48V, so that the output current maintains the maximum output. It is like a DC-DC transformer rather than a switch, which can minimize charge losses. While the PWM controller is only fixed at a point to generate electricity, the PWM controller is more like a switch without automatic tracking function.

3. The differences of input voltage range

The maximum input voltage of the PWM controller can only reach 50 volts.The maximum input voltage of the MPPT controller can reach 150 volts.Therefore the MPPT controller can it easier to match solar panels.

4. Different scope of application

1KW below equipment recommended PWM controller, 1KW above recommended MPPT controller, the greater the power, the more MPPT effect can be reflected.

PWM controller is recommended for devices less than 1KW. MPPT controller is recommended for devices 1KW above. The greater equipment capacity, the efficiency of the MPPT controller can be maximized.

Choosing between an MPPT (Maximum Power Point Tracking) and a PWM (Pulse Width Modulation) solar charge controller depends on several factors including your specific needs, budget, and the characteristics of your solar power system. Here’s how to make an informed decision:

MPPT Solar Charge Controller

Advantages:

• Efficiency: MPPT controllers are more efficient, especially in colder weather or when the solar panel voltage is higher than the battery voltage. They can convert excess voltage into amperage, improving overall efficiency.
• Flexibility: These controllers work well with different types of solar panels and can handle higher input voltages, allowing for longer wire runs from the panels to the controller without significant losses.
• Better Performance in Non-Ideal Conditions: MPPT controllers can harvest more energy during non-peak hours and under less-than-ideal conditions like partial shading.

Disadvantages:

• Cost: MPPT controllers are generally more expensive upfront compared to PWM controllers.
• Complexity: They tend to be more complex and may require more advanced settings.

PWM Solar Charge Controller

Advantages:

• Cost-Effective: PWM controllers are less expensive and are a good choice for smaller systems or where budget constraints exist.
• Simplicity: They are simpler to install and use, making them suitable for straightforward applications without the need for maximum efficiency.

Disadvantages:

• Less Efficient: PWM controllers are less efficient, particularly in cooler temperatures or when there is a significant difference between the solar panel voltage and the battery voltage.
• Limited Flexibility: They do not handle higher input voltages as effectively and are better suited for systems where the solar panel voltage matches closely with the battery voltage.

Considerations for Choosing:

• System Size and Budget: Larger systems often benefit more from MPPT technology due to increased efficiency gains. For smaller systems or tight budgets, PWM might be sufficient.
• Environmental Factors: If you live in areas with varying temperatures or have long cable runs from panels to the controller, MPPT would be more beneficial.
• Future Expansion: If you plan to expand your system in the future, investing in an MPPT controller now could save costs later by providing better scalability.