Surveillance in the sun
Wireless technology has revolutionized many industries and the security industry is no different.
Twenty years ago, wireless alarm contacts or camera systems were unimaginable. Today, the home security market is dominated by wireless technology which is also changing the way commercial systems are designed. Wireless point to point is now commonly used for long-range applications where expensive fibre optic cables would have otherwise been required in the past. All these advancements in wireless technology have increased the demand for solar power which many view as the key to creating a completely wireless system.
Of course, solar technology existed long before Wi-Fi or cellular, but with all the years of research behind solar energy, why is it not being used more in security applications? To answer this question, one simply needs to understand the components and limitations of solar power.
Solar power systems are very simple when broken down into their three parts: solar panels, charge controllers and batteries. There are many different types of solar panels and charge controllers as well as thousands of different battery types, but those differences are not important for the purposes of this article.
To understand how these systems operate we have to start with the batteries. Batteries store energy and are really the key to keeping solar-powered systems online during those rainy fall days when you may not see the sun for a week. Users may believe the batteries are only required to get through the nights, but in reality, batteries are drained anytime there is not sufficient sunlight on the panels, for example on overcast days. The number or size of batteries in your solar solution will determine how many days the system will stay online without direct sunlight.
The most well-known component of any solar solution is the solar panels that convert sunlight into electrical energy. What most people misunderstand about solar solutions is that the panels rarely power any equipment directly, but rather they recharge the batteries that ultimately provide power to other equipment. More panels mean the system can charge faster. This is important for areas where you may have very short periods of sunlight. For example, three panels over a one-hour period could provide the same charge as one panel over a three-hour period. This is extremely important to understand when designing a system for countries like Canada where many areas get less than two hours of sunlight each day during the winter months. To fully recharge the batteries in only a two-hour window requires a lot of panels.
The last component of any solar solution is the charge controller. The charge controller acts as an interconnect between the solar panels and the batteries. As mentioned earlier, solar panels convert sunlight into electricity, but since sunlight is inconsistent, so is the power output by the panels. Batteries are not designed to ingest this type of fluctuating voltage range, and that’s where the charge controller comes in.
The charge controller takes the wide swings in voltage from the solar panels, converts it to the correct voltage, and then manages the rate at which power is released into the batteries.
This brings us back to our original question, why are solar solutions not more popular in video surveillance? Video surveillance systems need to be online 24/7 year-round. This is a big challenge during long overcast winter months where costly solutions made up of large battery packs and multiple solar panels are required to take advantage of the short periods of sun.
Solar provides a valuable and environmentally friendly method to power non-critical infrastructure. It is also a good source of supplemental power where traditional AC power is available when needed. For video surveillance however, solar is only practical when traditional power is impossible or very expensive to acquire. In those cases, properly designed systems by experienced solar engineers can provide a viable solution.
Colin Bodbyl is the chief technology officer of Stealth Monitoring
This story appeared in the March 2019 edition of SP&T News Magazine.
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