HOW DOES A SOLAR LIGHTING SYSTEM WORK?
Many people who contact us do not have a full understanding of how a solar lighting system works, and that¡¯s understandable! There¡¯s often many questions, including does the system use batteries, what¡¯s a charge controller, how do the lights turn on, how big is the solar panel? These all are all good questions that we will address below.
The diagram below should help you to understand how a solar system works.
1. The process starts with the solar panel absorbing the suns energy and transferring it to the charge controller.
2. The charge controller regulates the power coming in from the solar panel, and uses the power to charge the rechargeable batteries. The charge controller makes sure the batteries do not over-charge or over-discharge.
3. When the sun sets, the solar panel sends a signal to the charge controller that it is night time. The charge controller will then turn on the light which is powered from the rechargeable batteries.
4. When the sun rises, the solar panel will send a signal to the charge controller and turn the light off. The cycle will then start over.
Solar panels are what collect the suns energy and convert it to DC power. This power is used to directly charge batteries with the use of a charge controller.
The size of the solar panel will depend on a few factors.
It depends on what it is that you are powering. It could be a 10 Watt light fixture, or a 100 Watt light fixture. The higher the power consumption, the bigger the solar panel will need to be.
The geographic location of where the solar panel is being installed has an impact on the size of the solar panel. A solar system powering a 10 Watt light will need a bigger solar panel if it is installed in Seattle, Washington, compared to Miami, Florida. This is because sun levels in Florida are considerably higher than the sun levels in Washington State.
The direction that the solar panel is facing and the angle it is installed will also have an impact on the size of the solar panel. To maximize the amount of the exposure to the sun, the solar panel should face due south. To maximize the performance of a lighting system during the winter months (the worst conditions for solar due to longer nights, shorter days and poor weather conditions) the solar panel should be installed at an angle 15 degrees plus the latitude of the installation site. For example the latitude of Atlanta, GA is approx. 33¡ãN so the appropriate angle for the solar panel would be approx. 48¡ã. If for some reason the solar panel has to face East or West, and/or needs to be installed flat on top of a structure, the solar panel will likely need to be bigger to make up for the unfavorable solar panel positioning.
The amount of time that the light will need to stay on for each night will also make an impact on the size of the solar panel. A 10 Watt light on for 14 hours will use more power than a 10 Watt light on for 6 hours. The longer the time the light will stay on for, the bigger the solar panel will need to be.
All solar systems use some type of battery, which surprises some people. Keep in mind that a solar panel absorbs the energy, it doesn¡¯t store it. A battery is required to store the energy which will power the light when the sun has gone down. The sizes and types of batteries supplied with solar systems vary greatly. Batteries can be small AA rechargeable batteries, lithium battery packs, or batteries similar in size to car batteries. The size and type of battery will depend on many of the same factors mentioned about solar panel sizing. The longer the light stays on for, and the higher the power consumption of the light, the bigger the battery will be. All of the systems we offer are supplied with a lockable weather proof battery enclosure to house the batteries.
Solar systems use a device to help regulate the energy collected from the solar panel, and transfer the energy to recharge the batteries. It could be a piece of circuity integrated into the lighting kit, or it can be a separate device called a charge controller. The charge controller will manage the power going to and from the batteries to prevent them from over-charging or over-discharging. The charge controller will also control when the light turns on and off. The solar panel will send a signal to the charge controller when the sun sets and rises, it will then turn the light on or off. Many charge controllers can be programmed to adjust the illumination time settings. A charge controller can be programmed to turn a light on from sunset to sunrise, or it could turn the light on for a certain amount of time after sunset and then turn off. They can also turn on for a certain amount of time after sunset, turn off, and then turn back on a certain amount of time before sunrise. We can also implement dimming, and motion sensors to save power.
Most solar lights use LEDs as a light source. LEDs are more energy efficient than older style bulbs such as incandescent bulbs, CFLs, high-pressure sodium or metal halide bulbs; meaning they can provide more light (lumens) using less power (Watts). The style of light fixture can vary greatly from decorative landscape lights, to flood lights, or to roadway and parking lot lights.