Please raise your hand if you've ever felt betrayed by the solar street lights you just installed. The night is starting to fall, the lights should come up, but they stay off. In this very moment you are probably cursing yourself for being enthusiastic about solar energy and its applications.
Sooner or later this is exactly what happens once you buy solar street light. You are told by the sales department of the company that their model of solar street light is a perfect fit for your application, throwing bunch of numbers and calculations right in front of your face. What they also tell you is that it will have 5 or more days of autonomy (this is just a fancy term used to explain that it will be/stay operational) once bad weather occurs.
Guess what! 99% of the time (except for you guys located around the equator) you will not have the autonomy you have been promised and you will feel deceived for the money you have invested into solar street lighting.
We have good news for you guys! The technology has evolved and today more than ever before, it is possible to achieve 365 days autonomy with your solar street light by applying remote management control and monitoring.
In this blog post, we will walk you through the basics of smart solar street light technology, how it works and what you need to know in order to make the right purchase decision next time you do it. Ready? Let's dive in.
Fundamentals of Smart Solar Street Lighting
• Solar Street Lighting - The Past
We will start with the basics. What are the key elements that you need to have in each solar street light in order to make it functional? Let's see:
- Solar Panel
- Solar Charger Controller/ Inverter (depending on the voltage in the system)
- LED Light
- Interconnected cables
In this blog post, we will presume that you know the basic configuration for solar panel, battery and led light and we will focus on additional components that you need to be aware of in order to make solar street lights intelligent, but above everything else functional. However, if you are in doubt check out this article where you will find more details depending on your needs.
• Smart Solar Street Lighting - The Future
Now, how do we make it smart? As a matter of fact it's not that hard, once you know what components to apply. Let's see:
- Smart off the grid controller (there is on-grid solution, but for the sake of simplicity we will talk about off-grid alone)
- Motion Sensor
- Temperature probe
- Software solution
Smart off the grid controller
The magic starts once you change your standard solar charger controller with the smart one. Smart solar charger controller performs the same functionality as the regular one, except for the fact that it has built in communication protocols (for you guys that want to know more on this topic check out this article) so that remote control and monitoring is made possible. Once you do this, you have given your street light communication options and now you can control it remotely from any location via Desktop, Mobile or Tablet application.
Motion Sensor and Temperature probe
What's more, when the brain of the system has been established, we just have to add couple of sensors in order to make it really smart and able to provide lighting just when we need it.
Motion sensor is a crucial part to have in the system since it is used to provide lighting when movement is registered. On the other hand, we need to install temperature sensor (probe) to be able to figure out the battery temperature and optimize its performance so that we can prolong battery lifecycle. It is the most expensive element thus more about battery optimization in our next blog session. For now it's enough to know that battery performance can be optimized, decreasing maintenance costs in the future.
Finally, once you have all of the system components in place you need a software solution that will enable you to proactively monitor and control each solar street light in real time.
In the next section we will explain how to use software solution in order to make solar street light functional throughout the year and to always have lights when you need them.
• Manage and control your lights remotely
Here comes the most exciting part, so let's jump into it.
Once we have real time remote control and monitoring over the system no matter where the smart solar street light is, we can observe the parameters, change them and adapt to different conditions and situations. What's more if you have a possibility to know what will happen in the future ( weather prediction) then nothing can surprise you and your system.
Cloud solution and data communication
Data is continuously streamed from smart solar charger controller to the cloud service. Data captured includes voltage and current readings for solar panels, load ports (LED light in our case), battery as well as battery temperature. Over 24 different indicators are also sent to the cloud to monitor services maintained by the controller. This data is stored in the Cloud to enable ongoing support, maintenance, and troubleshooting.
Having installed motion sensors on each pole with dimming functionality, we will have light on demand in crucial periods while saving energy during times when full light performance is not truly needed. For instance, the city of Barcelona saved 2-3 billion € in electricity by implementing motion sensors on part of the street light network in the city.
Adjusting lighting schedules for smart solar street light
Next, software application makes it simple to set up and change lighting profiles that automatically adjust based on time of the day. For example, if you know that pedestrian frequency is highest from 8 PM to 11 PM, you will adjust brightness to 100 % of light. However, after midnight you know that pedestrian frequency is very low thus you would dim the lights to 40% and turn on the motion sensor. Once someone is passing by, the lights would go to 100% brightness (you can even adjust how long the light will stay on 100 % once pedestrian traffic occurs).Just so you know, when you dim led lights from 100% to 40 % your eye would not see even notice the difference. This means that the light level from the pedestrian point of view stays the same whereas you save 60% of energy costs. Check out this video to see it in action.
Predicting the weather is the key
Without knowing what will happen in the future, you would not be able to optimize current energy levels. Let me give you an example; if we know that in the next 5 days we can expect rainy days without sun, we would set our smart solar system into conservative mode of lighting, saving vast amount of energy in order to stay operational. In addition, when the bad weather is behind us and we expect sunny conditions then we can go back to 100 % lighting performance. This is exactly why you need smart algorithms and weather predictability inside of your software application so that you can predict future events in order to optimize your current energy levels.
To conclude, solar street light have not been adopted so far as dependable substitute for traditional street lighting due to the fact that they are not reliable source of lighting. Times have changed and today with the help of smart technology, we are able to transform solar street lights into standardized lighting solution demystifying its bad reputation from the past.
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