Using solar power for security equipment

If you're considering using solar power for security equipment, can you answer 'Yes' to the six questions below?

Solar electric power is a valuable technology providing continuous, reliable and cost-effective power when used in appropriate applications. However, there are fundamental questions to consider when sizing and specifying solar for a site that has no access to utility power or where access is impractical. Understanding the answers to the following six questions will help determine if solar is an effective technology for powering equipment at such locations.

1. Have you identified your load configuration?
2. Is your load in a location with limited or no access to commercial (grid) power?
3. Does your load require power conditioning?
4. Is your site typically unattended year round?
5. Is your load operating in harsh environmental conditions?
6. Is your application critical in nature - is reliable power essential?

1. Have you identified your load configuration?

There is no technical barrier to the use of solar for any security load. Applications can include access control, alarms, system monitoring, video surveillance, CCTV and lighting, ranging from small single use applications to wide area surveillance projects. Equipment most commonly powered by solar includes a wide range of cameras (fixed zoom, PTZ, with or without fans) with associated sensors and alarms, wireless transmitters and radios.

However, the size of the array (the total collection of solar electric modules required) and the battery bank is directly proportional to the daily load requirement. This means that at a certain project size, a solar system can become very large and very expensive. It is a good idea to reduce the security application total load to as few watts as possible when considering solar energy. The sweet spot is for loads below 75 watts of continuous demand (3 kWh/d). Solar electric systems typically make great economic sense when powering loads at 300 watts of continuous demand (7 kWh/d) or less. For larger loads, we can consider solar systems in a hybrid combination with an on-demand generator, such as a diesel or propane generator set or fuel cells.

2. Is your load in a remote location with limited or no access to commercial (grid) power?

A solar electric system is an excellent remote-site technology since it is co-located with the load equipment. It does not require long-distance trenching of power lines. The power goes where the load goes, making solar electricity an ideal distributed power supply.

3. Does your load require power conditioning?

Solar is a DC technology. Solar electric modules and lead-acid batteries are DC devices, typically configured at 12V, 24V and 48V. Battery operating voltage is set to vary from -2% to +25%. If your load can operate within that voltage range, you can power it directly from the DC output of a solar electric system. If your load needs to operate in a tighter operating voltage tolerance (i.e. 5%) or if your load is operating on AC, power conditioning will be necessary (DC/DC converter or inverter). The losses related to this power conditioning need to be taken into account in the sizing of the solar solution.

4. Is your site typically unattended year round?

Solar electricity can be designed as almost a pure maintenance-free power technology. A solar electric system will operate unattended year round with only annual inspections required. If you have a remote site you plan to operate unattended for the bulk of the year, you will find solar electricity to be totally compatible with your equipment's maintenance regime.

5. Is your load operating in harsh environmental conditions?

Solar electric systems are designed to operate reliably in remote, rugged sites and are built to satisfy demanding environmental standards. Well-designed solar electric systems still operate successfully when exposed to climate extremes such as hurricanes, tropical rainforests, snow, corrosive salt air and excessive temperatures.

6. Is your application critical in nature - is reliable, continuous power essential?

Well-designed solar electric systems have been successfully powering a huge variety of industrial load equipment for the past 30 years. When properly sized, the rugged nature of solar systems makes them the most reliable form of power on earth.

If you can answer yes to all, or even most, of these six fundamental questions, solar is a power source to consider for your outdoor security equipment.

About the author: Bruce Wilson is the security sales manager for SunWize Technologies. Since 1992, the firm has been providing solar power sources to industry and government with applications in telecommunications, oil and gas, security and transportation.

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