Tilt Sensors used for Solar Tracking 

Solar tracking is the ability to automatically orient solar panels in a given direction.

The main goal is to increase the power output of solar panels by making them more perpendicular to the sun's rays.

It is achieved by using a tracking system that can detect the sun's position and adjust the angle of solar panels. A typical tracking system consists of a tilt sensor, a servo system, and a controller.

Tilt sensors are the core component of every solar tracking system. They provide the controller with information about the current position and angle of the solar panel.

The controller then calculates the desired position and sends signals to the servo system that adjusts the angle of solar panels.

What is a Tilt Sensor?

A tilt sensor, also known as an inclinometer, is a high-precision device that measures the slope, angle, and tilt of an object relative to the horizon.

It detects the inclination of a surface and provides output signals as a function of the inclination it senses.

In solar tracking, tilt sensors measure the elevation and/or horizontal angle of the sun, compute the data, and determine the best tilt angle needed for the solar collecting structures.

An electric current is usually used to transmit information to the tilt mechanism (controller) about the best tilt angle.

The sun's position changes with the time of day, season, and weather. Solar productivity is affected by these factors when using fixed roof solar panels or ground mounts.

When tilt sensors are used, the solar collectors are always aligned with the sun, regardless of the weather conditions. This is why tilt sensors are so useful in solar tracking.

How do Tilt Sensors Work?

A tilt sensor's main objective is to collect data about the sun’s position and relay the data to a controller or solar collector tilting structure.

The data collection part of tilt sensors can be likened to heliotropism (the motion of plant parts with respect to the direction of the sun).

When the sun rises, the sensors will begin tracking it, then follow it (while moving the solar panel structure) until the sunsets. In the absence of sun, the tracker resets to its original position, ready for the next day's tracking.

For tilt sensors to work as a complete tracking system, they need to be coupled with a controller or the tilting mechanism.

Once the tilt sensors have computed the sun’s elevation and/or its horizontal position of the sun, they display this information in an analog or digital format and transmit it to the tilt mechanism.

The tilt controllers use this data to calibrate and adjust the solar panels accordingly.

A tilt sensor solar tracking system is ideal for projects where there’s a limited amount of space. Nevertheless, they can be used on large projects to enhance their efficiency.

Types of Solar Tracking with Tilt Sensors

Two types of solar tracking can be achieved with tilt sensors: single-axis and dual-axis tracking.

Single-axis tracking

Single-axis tracking is the most basic form of sun-tracking. It moves the solar panel in a single direction along a horizontal plane while maintaining one tilt angle.

A single-axis tracker is usually used in smaller-scale projects since it only moves the solar panel in one direction.

Pros

• Not a complex mechanism
• Cheaper to install and maintain

Cons

• Limited use on large-scale projects

Dual-axis tracking

Dual-axis tracking is the more sophisticated form of solar tracking. It moves the solar panel in two directions (vertically and horizontally) to maximize the sun’s energy.

This type of solar tracking is usually found in large-scale projects where a small increase in energy efficiency can translate to a huge amount of energy gain.

Pros

• Produces higher yields compared to a single-axis tracking system
• Complex mechanism/harder to install and maintain
• More expensive

What to look for in a Tilt Sensor for a Solar PV System?

Protection rating (IP Degree)

Tilt sensors like solar modules are usually exposed to environmental and climate elements and it’s important to ensure that they can withstand this.

A tilt sensor's protection rating or IP degree is the only way to measure how reliable and stable it’ll be in outdoor applications. 

Every electrical component has an optimal operating temperature range. The operating temperature of a solar tilt sensor is either between -20°C to +60°C (with an IP68 rating) or 0°C to 65°C (with an IP67 rating).

If you’re using the tilt sensor in very harsh conditions, then it would be best to choose the IP68 rating. If not, the tilt sensor with an IP67 rating is fine as well since it can withstand low temperatures without any problems. 

Accuracy and Precision

Tilt sensors need to be accurate and precise when measuring the sun’s position. Inaccurate measurements can cause a solar tracking system not to perform optimally.

The best solar tilt sensors are those that can provide accurate and precise data on the sun's azimuth, elevation, and inclination.

A +/- 2° accuracy is usually good enough for most projects. However, some projects can benefit from tilt sensors with higher accuracy ratings depending on the project's location and scale.

For tilt sensors, accuracy and precision are crucial since it determines the effectiveness of solar tracking and, consequently, the calibration of the solar collectors.

High-precision tilt sensors detect even the slightest sun direction and angle changes and reflect that by rotating your solar panels accordingly.

You can expect a noticeable increase in the overall performance of your solar PV system with even the slightest tilt.

High precision tilt sensors are resistant to external electromagnetic interference, allowing them to perform even better in tracking the sun.

Cost

The average cost of a tilt sensor is around $100. If you’re on a budget, you can go for the low-cost tilt sensors that cost around $30.

You can spend upwards of $300 for tilt sensors that are more precise and capable of tilting in horizontal and vertical axes.

The second option is recommended if you want to get the most from the tilt sensors, but ultimately, you should only purchase what you can afford.

Taking the time to compare prices between brands, then selecting the one that seems most affordable, can help you save some amount.

Size and weight

The size of a tilt sensor doesn’t really affect its performance, but it does affect how easy/difficult it is to install.

If you’re looking for a tilt sensor that can be installed without too much effort, then you should look for the one with the right size and weight.

Tilt sensors are usually small and lightweight.

The average size of a tilt sensor is 14.5 x 21.2cm or 5.7×8.4in, with an average weight of 0.3kg or 12oz.

Type of output

There are two types of tilt sensors used for solar tracking: analog and digital. While both types work well in tracking the sun, digital tilt sensors offer more advanced features.

Digital tilt sensors can track solar positions more precisely and accurately. They also increase the overall reliability of a solar tracking system by letting you set a virtual target for the solar modules.

Analog tilt sensors are usually less expensive than digital tilt sensors. However, they are not as easy to customize and configure, which means you have limited control over the output of your solar tracking system.

Advantages of Tilt Sensors for Solar Tracking

There are many advantages of using tilt sensors for solar tracking. Here are some of the reasons why you should consider using solar tracking systems with tilt sensors:

Increased productivity

Tilt sensors increase the productivity of your solar panels by tracking and adjusting to the sun's position.

You can expect greater energy output from your solar PV system with tilt sensors, especially if there is a considerable change in the sun's azimuth, elevation, and inclination as it moves across the sky throughout the day.

Automatic tilting of solar panels to match the sun’s position throughout the day can increase power production by 10 % to 25%. This is a range because there’re some climatic conditions and latitude considerations to take into account.

Solar panels with no tilt systems will only reach production at certain hours– when the sun is directly shining on them. Solar panels with a tracking system always maintain peak production since they have enhanced solar collection at all times.

Space-saving

Tilt sensors can reduce your solar system's footprint since they add less bulk to the overall design.

With the 20% power production achieved by tilt sensors for solar tracking, you can reduce the number of solar panels you need to produce a certain amount of power.

Let’s say you need 16 fixed-mount solar panels to produce 4KW of power. With tilt sensors, you can produce the same amount with just 13 similarly rated solar panels.

Cutting out 3 solar panels from the array is a great way to save on space and optimize land usage.

We all know that space is one factor that has been holding back the implementation of solar. The fact that tilt sensors can help solve a portion of this problem is exciting.

Cost benefits

Tilt sensors are cheaper for solar tracking compared to other mechanisms such as optical encoders. The market price may be the same, but the maintenance cost is where the huge difference is.

Tilt sensors have no moving parts, so it’s cheaper to run and maintain them. The same can’t be said for other technologies such as optical encoders.

Moreover, the increased solar production shortens the ROI period of your solar system, meaning you get solar for free faster and for an extended period.

Disadvantages of Tilt Sensors for Solar Tracking

Tilt sensors are not without their own set of disadvantages.

Here are some of the disadvantages you should think about before implementing tilt sensors in your solar tracking system:

Complex designs for PV/solar collector systems

When tilt sensors are used in solar power projects, the designing phase can get complicated, especially if you are using more advanced tilt sensors. With tilt sensors solar tracking, you have to plan for:

• Additional wiring/ trenching
• More focused site preparation
• Use of non-conventional solar mounting systems
• Need for non-conventional mounting systems

Not suitable for extremely harsh conditions

Different weather conditions could affect the accuracy and precision of tilt sensors for solar tracking.

The accuracy of the tilt sensor’s measurement is likewise limited by weather conditions such as fog, heat, and other weather phenomena.

Despite tilt sensors' durability, they can break under harsh weather conditions. Continual snowfall, for instance, will cause tilt sensors to fail. Sensors will perform optimally in standard weather conditions, and specifically in warmer conditions.

For this reason, you need to pay more attention when evaluating the IP degree of the tilt sensors you’re looking to buy.

More expensive than traditional fixed racking

Tilt sensors add about $0.1 per watt to the cost of solar arrays. While this may seem like a small amount, it can add up to a substantial overall cost of a solar project.

Of course, the price increment is compensated by the other benefits of tilt sensors solar tracking, such as increased productivity.

The higher cost per watt of solar tracking makes tilt sensors and other tracking technologies more suitable for projects where space is limited.

Requires more maintenance than stationary systems

Due to the additional electrical components of tilt sensors, they need more focused maintenance.

Frequent checks must, for example, be done to ensure that the wiring is intact and the integration of the tilt sensors with the controllers is seamless.

To make the maintenance of tilt sensors hassle-free, you should invest in premium tilt sensors following the guidelines we discussed above.

Frequently Asked Questions

Conclusion

Tilt sensors are core components of solar tracking devices, and they serve one important function: to orient the solar panels/modules/structure towards sunlight.

Using tilt sensors for solar tracking ensures that your PV system is always at its maximum power output, regardless of the weather and time of day.