Circuit Boards for Solar Light systems (BMS, MCU Board, Inverter...)

Printed circuit boards, or PCBs, connect and mount components on a circuit board, and different circuit boards connect each other to form a functional system, like a solar light system. Speaking of circuit boards for solar light systems, the LED PCBs in aluminum or FR4, or copper substrate to be used for the light itself is the least you want to learn about. The circuit boards used for the solar MPPT (maximum power point tracking) charging, battery packs, and DC-DC power conversion to the MCU control board, LED driver, and inverter board are what you are most interested in.

PCBONLINE, an OEM PCB manufacturer, provides one-stop circuit boards for solar light systems. In our article, we will explore what circuit boards for a solar light system are.

Solar Light System Circuits of Different Complexity Levels

As functional complexity increases, a solar lighting system is no longer a simple single-board solution but a multi-board system that works in coordination.

Solar light systems, from the simplest lawn lights to high-power road lighting systems, have different circuitry complexity levels. Whether simple or complex, its circuit is determined by its application and quality tier.

There are basic lawn solar lights, household lights of medium complexity, and off-grid and solar street lights of the advanced tier.

Basic Lawn Solar Lights Circuit

A solar lawn light system using direct current (DC) is the most basic and cheapest, featuring a simple circuit.

Its circuit consists of:

• Solar panel for DC power generation (typically 2V to 6V),
• Charge control, whose simplest form uses a diode to prevent reverse current flow,
• Battery, usually 1 cell Ni-MH or 1 cell lithium,
• Light control switch, which detects ambient light intensity and automatically turns on at dusk
• LED driver for simple current limiting or boost conversion)

It requires no battery management system (BMS), no inverter module, no control IC, but only uses a photoresistor + MOS/transistor. Small and single-layer circuit boards are enough for this simple solar light circuit. Sometimes, it requires only a small PCB on the back of the solar panel.

The focus of the circuit board for the basic lawn solar circuit is the LED driver and light control section, but the overall circuit is still simple.

Household Solar Lights of Medium Complexity

A household solar light system requires charge management and battery management, so its circuit requires smarter control and protection.

Its circuit includes:

• Solar panel for PV input,
• Charge management module (MPPT or PWM),
• Lithium or LiFePO4 battery pack,
• BMS module for overcharge, over-discharge, and overcurrent protection,
• DC-DC conversion circuit, Boost/Buck for the LED,
• Light control + time control + Microcontroller (MCU),
• LED constant current driver providing high efficiency and stable brightness

A household solar light system requires multiple circuit boards for charge, protection, control, and an LED driver, and the control board manages energy and logic control. However, it is still a DC system without an inverter.

The focus of circuit boards in this solar light system is the control boards, which include solar charge management, battery BMS, and lighting control logic. The LED light PCB is merely the end-point carrier.

BMS circuit board made by PCBONLINE

Off-Grid and Solar Street Lights of the Advanced Tier

An off-grid solar light system, such as solar street lights, is a complex architecture with a complete circuit that closely resembles a mini-PV system.

Such an advanced off-grid solar light circuit includes:

• Solar panel array from 18V to 36V or even higher,
• MPPT charge controller to achieve maximum efficiency charging,
• Battery pack with a cell connection system (CCS), a BMS, and multi-series Lithium or LiFePO4 cells,
• DC-DC converter or DC-AC inverter (some may even output 220V),
• Load drive control for smart dimming, timing, and remote communication,
• Communication and sensing (LoRa, illumination, temperature, current detection, etc.)

Inverter circuit board made by PCBONLINE

The PCB design of the circuit boards for the off-grid solar light system has quite a lot to focus:

• Safety isolation between the high-voltage DC input and the buck circuit,
• Copper thickness design and thermal management for high-current paths, for example, PCB busbar,
• Integration of MCU control logic, power management unit, and BMS interface
• Electromagnetic compatibility (EMC) and lightning protection design

Still, the main control circuit boards, including charge control, energy management, and BMS interface, are the core circuit boards. The LED light PCB and solar panel are merely peripheral modules.

For a straightforward overview of the different solar light circuitry, here's a table.

Circuit Boards for Mid to Advanced Solar Light Systems

What are the circuit boards used in household or street solar light systems? PCBONLINE manufactures and assembles these high-current PCBAs used for solar systems, and below is our explanation of these circuit boards.

A typical solar light system architecture is as follows.

What about the electrical relationships between the different circuit boards for the solar light system? You can check the following table.

Depending on the solar light system types, the number of circuit boards for a solar light system ranges from three to eight.

• Medium-power solar light (20–40W): 3–4 circuit boards, and they are MPPT + BMS + LED driver + control board.
• Smart garden/integrated streetlight (50–100W): 4–6 circuit boards, and they include an MCU, a light sensor, and a DC-DC conversion board.
• Off-grid solar lighting system (>100W or with AC output): 6–8 circuit boards, which include an inverter and communication boards.

Partner with PCBONLINE for One-stop Circuit Boards for Solar Lights

PCBONLINE is committed to PCB manufacturing and assembly for solar, not only solar energy devices like solar light systems. We are especially good at high-current PCBAs because we have rich experience in thermal management and large/small current separation.

Founded in 2005, PCBONLINE has two large advanced PCB manufacturing bases, one PCB assembly factory, stable supply chains, and an R&D team to provide you with solar light system circuit boards under one roof.

If you want to get R&D assistance or get a quote for your solder light systems, PCBONLINE is pleased to receive your message and provide help and PCBA manufacturing services. Please email info@pcbonline.com to reach out to us. We will provide one-on-one engineering support throughout your project.

Conclusion

Circuit boards for a medium to high-end solar light system include a BMS for battery protection and monitoring, a solar MPPT board for power regulation and charging control, a DC-DC conversion board for power conversion, an LED driver board for constant-current output to LEDs, and a main MCU control board for system logic and coordination. PCBONLINE is proud to lead the high-current PCBA manufacturing for solar energy applications. Contact us to order our turnkey circuit boards for solar lights and see how we can support your green energy initiatives.