Off grid led lighting-solar lighting has been there for so many years. You probably seen this in your neighbor’s garden. This low lumen output solar panel charged led light with small battery inside if fully charged by sunlight would run 6-10 hrs. will automatic on at dark.
Can we use this technology at large scale outdoor roadway lighting ,area lighting, municipal lighting at sunniest regions ?
I bet most drivers will notice this type solar power led speed sign and noticed it may not work at late evening or really cloudy days.
so the first question of that is how reliable of the solar lighting technology ? what is the system life and operational runtime when it on battery power?
What is the major system component is solar power off grid led lighting?
1) Solar panel, this is the source of the power for the system. the photovoltaic solar panel will convert sunlight energy into electricity to charge the battery during the day. There are several different types of solar cells in the solar panel with different conversion efficiency and cost: monocrystalline silicon(15%-20%), polycrystalline silicon(13%-16%), and thin film(7% to 18%).
2) Battery, it is used to storage the power generated by the solar panel and use it when lighting is needed. There are a few different types of batteries used in photovoltaic power storage: Lead Acid,Lithium Iron Phosphate, Nickel Cadmium. Different type of battery require different type of charging and discharging regime due to its chemicals restraints and limits.
3)LED light fixture, where the led is powered by the battery to convert electricity to light. The led fixture need to be designed to power directly with DC power from the battery which typical at 12V ,24V.
4) Power conversion electronics and controller for charging and discharging the battery. solar charger adapts the output from the solar panels to battery storage system. The charging system typical needs built-in maximum power tracker control to ensure that the maximum solar power available is processed in the optimal manner into the battery system to achieve better battery life. The discharging (led driver) also need to monitor battery capacity to not over depleting then damage the battery.
5) Other lighting fixture controller such as external photo sensor or wireless communication module built in for operation status monitoring and maintenance.
The off grid power system is intrinsically a complex electrical system with a lot system components works together seamlessly. This also mean system reliability is pending on multiple components that may not work well together. If different component designed by and supplied by different suppliers, there could be incompatibility issues .
There are many benefits of total off grid solar led lighting systems ,such as :
1) focus on delivery of light not the whole infrastructure( no more utility power wiring)
2) no utility bill by off grid using renewable energy -solar photovoltaic
3) no power outage concern with battery power even operational without sunlight
4) energy efficient solar power led lighting reduced overall energy consumption and carbon foot print overall
There are a lot companies already in this market that have provided a lot great products and solutions.
it has been in solar lighting business since 2004. It address different types of market needs and also offer all-in-one solar lighting products.
its all-in-one solar street led light features:
- Impact-Resistant Monocrystalline Solar Panel
- Optional Dual-Sided Light Bars
- Extruded and anodized aluminum housing
- MPPT charge controller
- 160-180 lumens per watt
- Phillips 5050 chips
- LiFePO4 battery
- Two- 15 Meter / 50 Foot motion sensors
- Built-in timer
- Programmable by remote control
- Resistant to Category 5 Hurricane
- Light Shields
FlexSol Solutions
FlexSol Solutions has devised a unique way of make curved cylindrical solar panels with modular design that use high efficiency(upto 23%) monocrystalline silicon solar cell . The solar panel works with highly reliable lithium batteries that can tolerate high temperature and lasts longer. It also integrates wireless remote communication for remote management and control.
one of biggest concern is still about the reliability of the solar panels and battery. when solar lighting sit in outdoor condition , the harsh environment like direct Sunlight UV exposure ,high temperature high humidity and weather proof cable and connection between subsystem put a much higher demand on system design and reliability testing.
Both CSA and UL have the PV and environmental testing facilities to help manufactures to do design validation testing. UL has created
UL8801 Outline of Investigation for PV luminaire system in 2020.
The big focus of UL 8801 is on bringing all the system components together in a way that helps ensure the power flow between them aligns with their individual capabilities, system-level cumulative risks (such as heat generation) are properly evaluated, and individual component failure modes are adequately managed by the system control features. As investigation experiences accumulate and feedback is received from interested parties, UL expects to issue a new edition of the outline with updates and revisions.
Overall solar lighting is not for big time yet due to the complexity of system which make it hard to do a highly integrated design at a really cost effective way. The current novelty use has taught lighting manufacture and PV system integrator a lot about the PV module and led technology. with the more advancement and cost parity on some high storage capacity battery technologies, we will see a boom in off grid solar power street lighting products according to a 2020 market research.
