Solar panels are an excellent way to reduce your dependence on fossil fuels and they’re also relatively inexpensive and easy to install. However, their output can vary significantly depending on the amount of sunlight they’re exposed to. This is where Maximum Power Point Tracking (MPPT) can help.
MPPT is a technique that allows you to get the most out of your solar panel by tracking the point at which it produces the most power and then directing that power to where it’s needed most. MPPT ensures that your solar panel operates at its maximum efficiency, no matter what the conditions are like outside.
For this article, I wanted to take a deeper look into maximum power point tracking and explain what it is, how it works, and how it could help power your entire home…even after several days with limited sun exposure.
What Does Maximum Power Point Tracking Do?
Maximum power point tracking (MPPT) is a technique used commonly with solar panels and wind turbines to maximize their power output by matching the impedance of the generator to the load. The maximum power point (MPP) of a solar panel or wind turbine is the operating point where the maximum output power occurs.
The MPP varies with temperature, Solar Irradiance, and wind speed (for wind turbines) so, the goal of MPPT is to extract the maximum available power from the renewable resource by constantly adjusting the operating point to match changing conditions. In short, maximum power point trackers allow you to produce more energy by actively finding the best position.
How Does Maximum Power Point Tracking Work?
A maximum power point tracker (MPPT) is an electronic DC to DC converter that optimizes the match between the solar array (PV panels), and the battery bank or utility grid. They are also used with other renewable energy systems, such as small wind turbines but for the purpose of this article, we’ll stick to solar panels.
Maximum power point tracking is based on the fact that, for each condition of solar isolation and temperature, the solar module produces a unique electrical power versus current and voltage characteristic curve. The actual operating point of the solar module will be determined by the load that is attached to the module and is tracked by a specific algorithm.
There are many different types of MPPT algorithms, but they all have one common goal: to find and maintain operation at the Maximum Power Point (MPP). The most common type of algorithm used in Maximum Power Point Tracking systems is Perturb and Observe (P;O).
This type of algorithm adjusts the duty cycle of a DC-to-DC converter connected between the renewable resource and load until it finds an increase or decrease in output power. It then maintains operation at that duty cycle until conditions change again.
There are also a number of different MPPT controllers on the market, but they all work in essentially the same way: by constantly monitoring the voltage and current output of your solar panel (or array), they calculate the point at which those two values produce maximum power output (the “maximum power point”).
Why Do You Need Maximum Power Point Tracking?
As I mentioned earlier, the output of a solar panel can vary significantly depending on the amount of sunlight it’s exposed to. This is due to the fact that the voltage and current output of a solar panel is not linear. In other words, as the amount of sunlight increases, the voltage and current output of the panel does not increase at the same rate.
This means that if you’re not careful, your solar panel may not be able to provide enough power for all of your needs. This non-linear relationship between voltage and current is what’s known as the “I-V curve” of a solar panel. The I-V curve is unique to each solar panel and can change depending on the temperature and amount of sunlight the panel is exposed to.
To make things even more complicated, the maximum power point can change depending on the conditions the panel is exposed to. For example, as the temperature of a solar panel increases, the maximum power point shifts to a higher voltage. But this is where MPPT can help you out.
By constantly monitoring the voltage and current output of your solar panel, an MPPT system can calculate the maximum power point and then adjust the load on the panel to match it. This ensures that your solar panel always operates at its maximum efficiency, no matter what the conditions are like outside.
MPPT systems are particularly useful in off-grid applications, where the amount of sunlight can vary significantly from day to day. By constantly tracking the maximum power point, an MPPT system can ensure that your solar panel is always operating at peak efficiency, even on days with limited sun exposure.
How Much Do MPPT Devices Cost?
More powerful MMPT devices designed for larger arrays can cost as much as $500 but a smaller 10amp device can cost as low as $40. The overall cost of an MPPT device depends on the type of device you choose, the size of your solar panel array, and the features you need.
Be careful purchasing a cheap MPPT, though. You’ll get what you pay for so take time to research various features and find an MPPT that suits your solar array and daily solar exposure.
How Much Of A Difference Do MPPT Devices Actually Make?
A good MPPT can increase the power output of your solar panel by as much as 30%. That means if your solar panel is rated for 100 watts, an MPPT could increase its output to as much as 130 watts.
$500 for a quality MPPT device may seem steep but in the grand scheme of your entire array, it’s really a small percentage of the total cost. Nevertheless, you may be wondering if it’s worth spending so much on a single tracker. How much of a difference would it really make?
In addition, an MPPT can help you get the most out of your solar panel on days with limited sun exposure. This is because an MPPT can track the maximum power point of your solar panel, even as the conditions outside change. This means that on a cloudy day, an MPPT can help you get more power out of your solar panel than you would without one.
Finally, an MPPT can help prolong the life of your solar panel by protecting it from damage caused by over-voltage. Most solar panels are designed to operate at a voltage of 18 volts. However, when the sun is shining bright, the voltage of a solar panel can increase to as high as 30 volts. If this happens, it can damage your solar panel or the batteries it’s connected to.
An MPPT can prevent this by constantly monitoring the voltage of your solar panel and then reducing the load on the panel when the voltage gets too high. This not only protects your solar panel from damage, but it also helps to prolong its life by preventing it from being exposed to voltages that are too high for it to handle.
So, as you can see, an MPPT can make a big difference in the performance of your solar panel. If you’re serious about getting the most out of your solar panel, an MPPT is a worthwhile investment.
Are There Any Disadvantages To Using An MPPT?
There are a few disadvantages to using MPPT, but they are relatively minor.
- First – MPPT systems can be more expensive than non-MPPT systems. This is because they require more sophisticated electronics and often come with additional features, such as voltage and current monitoring. That being said, though, it’s pretty much required to use an MPPT if your array consists of more than two panels.
- Second – MPPT systems can introduce a small amount of power loss. This is because they need to convert the DC output of your solar panel to AC and then back to DC again. However, this power loss is usually less than 5%, so it’s not usually a cause for concern.
And that’s really about it! As you can see, maximum power point tracking is a great way to get the most out of your solar panel, especially in off-grid applications. So, if you’re looking for a way to increase the efficiency of your solar panel, an MPPT system is definitely worth considering.