This project aims to build a smart solar-powered streetlight system utilising a lithium-ion-based system and equipped with Internet of Things (IoT) sensors to collect environmental data such as temperature and air quality remotely. This new system will provide us with an environmentally-friendly and potentially cost-effective means of keeping our streets bright at night.
Photo by Asia Chang on Unsplash
At the present, streetlights rely on conventional electrical systems to provide them with power at night. However, there is potential for streetlights to be outfitted with standalone solar-powered systems to reduce operating costs and environmental impacts. Dr. Tey Kok Soon and his team (Mr. Immad Shams and Mr. Luqman Hakim Hashim) at the University of Malaya have been working on one such system.
As conventional lead acid batteries are too bulky and have short lifespans, Dr. Tey opted to utilise a lithium-ion battery base in order to achieve optimum utilisation of available solar energy. The lithium-ion battery pack is built from a series of parallel connected lithium-ion battery cells (see Figure 1); this particular pack consists of four series-connected cells with a total nominal voltage of 14.8 volt. Without proper management, the voltage of the battery cells may be different from each other; battery cell with lower voltage will limit the current supply of the whole string and thus affect the performance of the whole pack. To counteract this problem, a voltage balancer circuit is used to equalize the voltages of the series-connected cells. Furthermore, the storage system is protected by a smart control system to prevent overcharging and deep discharge circumstances.
The system it equipped with a light-dependent resistor (LDR) in order to detect sunlight availability. The LDR sensor detects a sufficiently high level of sunlight intensity, the system will automatically begin charging the battery pack and will stop when the sunlight intensity drops (i.e. at night-time). The LDR sensor will also determine the operation of the LED light, automatically switching it on when it is getting darker. The proposed system is also equipped with maximum power point tracking (MPPT) to track the maximum power from the solar panel under different weather conditions, maximizing the generation and usage of solar energy. Finally, the system has been equipped with Internet-of-Things (IoT)-based sensors designed to detect the surrounding environment and air-quality based on dust, humidity and temperature. The data is automatically collected and can be sent to the main server via Wi-Fi connection.
A lab prototype with a 150 W solar panel has been built (see Figures 4 & 5) and has already been validated, with the printed circuit board for the whole system currently undergoing validation. As of now, the next step is to properly combine both systems (battery bank and IoT sensors) into a single working system.
Solar-powered standalone battery-operated streetlights can be powered without needing AC grid wiring especially in more remote or rural areas. This battery system can be easily implemented in any location with high levels of sunlight available and can provide any voltage range required via stacking up the battery packs. In addition to streetlights, this solar-powered battery system can be implemented into other appliances such as USB phone chargers and information boards at bus or train stations. This new battery system will help pave the way towards more environmentally-friendly and potentially cost-effective power systems.
Figure 1: Lithium-ion battery pack.
Figure 2: Block diagram of the proposed system
Figure 3: Overall System Board
Figure 4: Battery Pack
Figure 5: System under validation
Figure 6: Data collected in server displayed in Dashboard
Author and researcher featured:
Associate Prof. Dr. Tey Kok Soon Department of Computer System & Technology, Faculty of Computer Science and Information Technology firstname.lastname@example.org,
Copyedit: Michael Hoe Guang Jian (email@example.com)