Dual MPPT Vs Single MPPT-Which is Better?


The four-letter abbreviation MPPT is frequently used in the solar business, but few people are familiar with it. Understanding the meaning of MPPT and how it works is crucial because doing so can enable a user to increase the efficiency of his/her photovoltaic system and thus its profitability. But there are different types and functions such as dual mppt and single mppt. So, what is dual mppt and what is meant by dual mppt vs single mppt? Read the blog to learn about MPPT and other related facts.

What is an MPPT? What is Dual Mppt?

MPPT or Maximum Power Point Tracker is a circuit (typically a DC-to-DC converter). It is used in a majority of modern photovoltaic inverters. Its job is to maximize the energy available from the connected solar module arrays and that too at any time during its operation.

As you have already learned about what an MPPT is, let’s about what is dual MPPT. A dual MPPT offers two channels, and the algorithm permits two strings per input without fusing. With regard to the data in the table, an inverter with dual-MPPT functionality enables significantly more system design flexibility, substantial cost savings, and higher amounts of harvested energy.

Dual MPPT Vs Single MPPT-Which is Better?

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Whenever the topic comes about dual MPPT vs single MPPT, the question arises which is much more efficient? Let us find out the answer to this question in the following lines. Simply stated, dual MPPTs are superior to one in the vast majority of applications with two strings or more. Check out the chart below for evidence to back up this claim.

Single Inverter AttributeSingle MPPTDual MPPT
Allow connecting arrays with different solar azimuth anglesNoYes
Allow connecting arrays with different solar tilt anglesNoYes
Allow connecting arrays with different string lengthsNoYes
Allow connecting strings of dissimilar modulesNoYes
Allow connection of more than two strings without combiner fusingNoYes
Provide better monitoring granularityNoYes

Without the need for fusing, dual MPPT’s two channels, and code enables two strings per input.

If you thoroughly consider the entries in the provided comparison table, you’ll notice that an inverter with dual-MPPT functionality allows significant cost savings, much greater system design flexibility, and higher levels of harvested energy.

Why is a MPPT Necessary?

A solar module has a limited energy DC supply. It also has internal impedances that vary throughout the course of the day. These variations are primarily dependent on the level of solar irradiance impinging on the module face as well as the cell temperature. This results in a lower efficiency operation for the connected strings, this is unless the inverter can match the strings to extract maximum power.

The MPPT circuit constantly monitors the array current and voltage. It aims to drive the operating point of the inverter to the maximum power point of the array. This way there will be a higher energy harvest.

Also Read: What is MPPT Charge Controller?

What is the Advantages of Multiple MPPTs of an Inverter?

After learning about the better option between dual MPPT vs single MPPT, you must also be curious to learn what is the advantages of multiple MPPTs of an inverter. Well, the following pointers will solve your curiosity-

1. Since each MPPT can only accommodate one string length, having more MPPTs results in more design flexibility. For instance, a design using a multiple-MPPT inverter can have different string lengths based on the needs of the roof, with some having 20 panels and others having 21 panels. All threads going into a single MPPT inverter must be the same length to be mixed on a roof

2. Since only one module type can be used with each MPPT, so using more MPPTs will allow module ratings or types to be mixed on a roof. For instance, if 275W modules are best suited for the available roof space, one area of the roof could use 320W modules. With a single MPPT inverter, all modules connected into one inverter must be the same model.

Also See: 6 Best MPPT Solar Charge Controllers

3. Allowing for setups on multiple-facet roofs with various pitch angles. When compared to modules mounted on the west side of the roof, those mounted on the east side will generate much less current. While a multi-MPPT inverter could use both current values and thus completely utilize the modules with greater current, a single MPPT inverter would output power based on the lower current value. A multi-MPPT inverter can produce 2% to 3% more output than a single-MPPT one for designs with an east-west orientation.

4. A shaded module produces a significantly lower current. Due to this, the current of the whole string will drop down to the value of the affected module. However, on a multi-MPPT inverter, there are only two strings per MPPT. This causes the current from two strings to drop. In the case of a single MPPT inverter, even if only a single module is shaded, the entire array current will drop.

With this, we have arrived at the end of this blog and till now you should have gotten a fair idea about dual MPPT vs single MPPT. Now you know which one is better. These terms will no longer confuse you in the future.

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