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Many options come up when you do a general search on Google for Solar Powered Street Lights. In addition, many shops on Google, Amazon, and other mass retailers have lights ranging from tiny little lights to some larger scale systems that are all mass-produced. This is all causing a major problem in the commercial solar-powered street light market.
With many markets, mass production is how to operate; however, this hurts the solar industry, especially in the lighting sector. With so much misinformation about what these mass-produced solar powered street lights can do, it is hard to make sense of everything and traverse this landscape to find a quality system.
I wanted to take a few minutes of your time to go over some of these various problems, what to look out for, and why purchasing a light from a quality manufacturer will leave you in a better place overall.
Solar Power Street Light Component Comparison
The best way I could think of doing this is a component comparison. Let's break down each component and compare what a 300 Watt Outdoor Solar LED Street Light is available on Amazon compared to what a commercially designed solar street light is made of.
Solar Panel
One of these mass-produced systems provides a solar panel typically mounted on top of the fixture and integrated together. However, for this comparison, I chose to go with a smaller system that still has its own solar panel, separate from the fixture, to be more similar to a commercial setup.
The solar panel is 27.5" x 13.8", so at maximum is around a 40-Watt panel. Doing some basic math, this means that the panel produces around 90 Watt hours if you are in an area with 3 hours of solar insolation per day. That isn't much power.
A typical commercial solar lighting system has a much larger solar panel, typically starting at 150 Watts, which is 58.25" x 26.25", going up to much larger systems with solar arrays that are 80" x 66" or larger with some manufacturers. That means that a lot more power is being produced, ensuring the batteries receive the full charge required to operate the light at night.
The panel mounts are also much different. The small panel mounts to the fixture head, or separately on the pole, with thin metal straps. These can easily be torn off in a high wind event or bad storm. So not only do you now have to replace the panel or system as a whole, but it also wastes resources that could be used to create a better product.
A commercial solar lighting system mount uses either industry standard mounts that have been engineered to handle the solar or their own custom mounts like SEPCO has developed, that can withstand up to 170 MPH winds in some cases. Having the solar panel mounts engineered to these standards ensures your system will stand up to just about anything mother nature throws at it.
Solar Battery
The solar battery should be sized to provide a backup for times of bad weather and for the worst-case scenario, such as a long winter night. Most of these package units have a couple of little batteries, usually lithium-ion, but only hold a charge for a night or two at best, operating at the most minimal output. On top of that, they typically need perfect conditions to charge the batteries back to full. This means that even one bad day can greatly increase failure probability. Plus, with the larger discharge, the battery cycles are low and will require the batteries to be replaced every year or two.
A commercial solar lighting system will come with a minimum of three nights of full operation backup with a Lithium option or five or more nights of backup for a GEL/AGM option. The sizing allows the system to operate with more than one day of bad weather, which is common in northern climates and allows the batteries to last many years. Not only does this reduce maintenance costs, but it also reduces a ton of waste.
Understanding climates is also important with the battery assemblies. For example, a Lithium battery doesn't have the capabilities to operate in extreme cold or hot climates; therefore, they are only good for areas with a more mild climate than Arizona or Maine. On the other hand, GEL batteries operate till -40° and are also non-hazardous, air shippable, etc.
LED Light Fixture
There is a ton of misinformation that is passed around when it comes to LED light fixtures. For example, the top performance of an LED module is 220 LpW; however, that is raw lumen data and not actual performance with the drivers, optics, etc. Honest companies show the amount of light produced after all the various components are used, showcasing the real data and the actual light output in use cases.
Another problem we see a lot is using cheap materials in the manufacturing of the fixture heads. The metal rusts or degrades long before the LED modules should, making the fixture heads themselves something that needs replacing way too soon, increasing costs to the end user.
Die-cast aluminum is the industry standard material used for fixture production with good finish powder coats or paints that can stand up to many different weather conditions, including snow, salt spray, dust, and more. An LED can last up to 100K hours, or 22 years on average, so the fixture housing should last just as long.
Solar Controls
The solar control system plays a huge role in ensuring your system operates as prescribed as it is the system's brain. That means if the lights are supposed to operate from dusk to dawn, the controller will keep the lights active while watching battery levels and other system conditions.
Many solar lighting systems state that they operate from dusk to dawn; however, that doesn't mean that they operate on at full output from dusk to dawn, though that may be what you are led to believe. Instead, many of the cheaper lights on the market operate at a reduced output, usually around 10% of full, or even sometimes off, until motion is detected. Then the lights kick on at full for a few seconds until no more motion is detected, then reducing or turning back off.
This is okay where sustained light levels are not required, but we are seeing this more and more in specifications in a hidden way. Instead of sizing the system to operate properly, many companies are shorting the solar and/or the battery to save costs initially and stating that the light operates from dusk to dawn, failing to mention the use of motion or other operation profiles.
Cutting corners with these types of controls, especially when lighting is for safety and security, adds liabilities to the end user and puts people in danger.
Fixture Arms
Fixture brackets hold the fixture to the pole or wall; however, not using a metal that will stand up to the elements will leave you with a system falling apart way before it should. The fixture arm should be made of good quality painted steel or marine grade aluminum and use stainless steel fasteners to hold it to the pole. Thin, cheap aluminum or steel will degrade, rust, and fall apart long before it should.
Poles
We see two main problems in the solar lighting industry regarding poles; lack of wind loading and structural integrity. This is problematic because the system could fall if there is a wind event or snow load that overloads the pole, meaning that the end user can be left holding the liabilities, especially if someone gets hurt.
Instead, having the poles designed to handle the added load of the solar power assembly, the system weight and EPA, with the local wind load requirements, will ensure that the system will stand up to mother nature. No worries of liabilities of the solar lights falling and causing harm to people or property in a high wind event situation or even a bad storm.
Learning About Sun Hours
Now that we have covered various components, let's look at one thing that is completely missed by many – Sun Hours. Sun hours are calculated by the total charge produced by the sun throughout the day. At 9 AM, it only produces about 10% of its charge, same with at 4 PM. Solar noon is the only time it is producing at 100% charge. The total is what is used in solar calculations.
In most southern areas, this ranges from 3.5 sun hours up to just over 5 sun hours in the winter. In the northern climate, it can be as low as a single sun hour in the winter months. Understanding your area's sun hours is crucial to understanding if your solar lighting system is sized properly.
This information is gathered from NREL or National Resources Canada, a 3rd party source that collects this data from various locations around the world. This data is then compiled and yearly and monthly averages are provided so that solar systems, both on and off-grid, can be sized accordingly.
Most off-the-shelf systems do not use this when doing system sizing. Instead, they use a one-size-fits-all approach and then use 6-8 or 8-10 hours of direct sunlight to charge. Unfortunately, one hour of direct sunlight in Maine is much different than one hour of direct sunlight south Florida during different times of the year. Therefore, this information is subjective and useless in the solar industry.
Instead, having the system sized to the amount of sunlight available in your location and the needs of the system to produce a full charge is critical to the product's lifespan. Not only will this produce a system that lasts a long time, but the system will also be more reliable, even when everything isn't perfect.
Light Distributions
Many of the light fixtures used in the mass-produced systems have zero optics other than shoot out as much light as possible in as many directions as possible. There is no care to what type of light optic is used for what type of application, nor if the light shining on the ground is all in one small spot or spread out in a set pattern.
Light distributions are important when it comes to many types of lighting applications. For example, a Type 2 distribution produces light in a long, linear fashion, while a Type 4 distribution produces light for a larger area in front of the fixture, but doesn't go as far out to each side from the fixture. Understanding these aspects are important to producing a system that will illuminate the area required.
If you have a long pathway, say 1000' long, and you use type 2 optics on a fixture, you will have lights spaced probably around 100' between poles, needing a total of 10 or so poles along this pathway. However, if you take the same pathway and use a fixture that only produces light in a round area on the ground, you may need double or triple the mount of fixtures to produce the same light levels along the pathway.
Now the installation costs can go up because the number of systems you have to install has increased, the light isn't as even along the pathway with hot spots and dark areas, and the overall look of a project can look less thought out and more thrown together.
Lumens vs. Watts
Do you know the difference between a lumen and a watt? A lumen is the amount of light produced by the LED and the watt is the amount of power the LED requires to operate. A 100-Watt LED fixture can produce anywhere between 50 and 200 lumens per watt and have very different lighting than one another.
Understanding how bright a light fixture is by reading the data published by the fixture manufacturer and LED company, and by producing light layouts using industry-specific software will help you visualize how bright the light is. This will ensure you have the correct amount of light around a site, with no hot spots or dark areas, making for good visibility.
Understanding Operation
Many lights state that they operate from dusk to dawn, but this statement can be false. The light may operate from dusk to dawn, but only when motion is detected. Technically, the light is operating from dusk to dawn, but only has the capacity to operate an hour or two at full output. This means that the light is not on the rest of the time.
In some cases, the lights operate at a reduced output from dusk to dawn with motion to full. This too is not always acceptable in projects where sustained light levels are required.
These operational changes are not always easily found on some mass-produced system specifications as many companies like to hide this information. Reading the fine print and researching will ensure you understand exactly what to expect from the lighting system.
System Backup
The last piece I want to hit on is the system backup. There will be times where the sun doesn't shine as bright and you can't produce a full charge in a single day. So having plenty of autonomy, or backup, is necessary to ensure that the solar streetlight will operate as specified.
GEL and AGM batteries should have a minimum of five nights backup to extend the life of the battery and provide the required autonomy. Lithium batteries can reduce to three days backup, but should only be used in the correct climates. If you live in a very cold or hot climate, Lithium isn't going to work properly and should instead opt for the older technology.
Conclusion
If sustained light levels are required throughout the night, the system must meet specific wind load requirements, needs plenty of backup, and needs to last for years to come; then an all-in-one mass-produced system will not meet your needs. Instead, a commercially designed solar powered street light is required to maintain illumination and provide a system that will stand up to the test of time. See how SEPCO can work with you to determine the best system to meet your needs and save you money in the meantime.
