Solar Power Manager for 12V Lead-Acid Battery

The Solar Power Manager for 12V Lead-Acid Battery is a medium-power solar management module designed for off-grid renewable energy and IoT projects. Capable of charging 12V lead-acid batteries at up to 4A from standard 18V solar panels, it delivers multiple regulated 12V and 5V outputs for loads up to 100W. It is ideal for makers, engineering students, and hobbyists building autonomous outdoor stations, security setups, agricultural devices, and robotics.

High-efficiency MPPT solar charging

Powered by the CN3767 management IC with a fixed 18V MPPT algorithm, the module maximises solar energy harvesting from 15V to 25V panels. It achieves an average charging efficiency of 94% and improves performance by 10% to 30% compared to standard PWM controllers.

Board overview and layout

The compact 68mm by 68mm board provides clear status indicators and dedicated connection points for solar input, 12V lead-acid batteries, and regulated loads. Included aluminium cooling fins and thermal pads ensure effective heat dissipation across temperatures ranging from -40°C to 85°C.

Off-grid deployment and integration

Designed to simplify renewable power integration, this module easily connects standard 18V solar panels to 12V lead-acid batteries. It offers a dependable power foundation for off-grid street lighting, environmental monitoring stations, pumps, and field robotics.

Controllable dual high-power outputs

The board features a high-current 12V 8A output (OUT2), a 5V 5A output (OUT1), and two 5V 2.5A USB ports supporting common charging protocols. Except for USB1, every output can be dynamically switched on and off using 3.3V or 5V microcontroller I/O pins to manage system power consumption.

Dedicated four-stage battery management

Lead-acid batteries are safely managed through trickle, constant current, constant voltage, and float charging cycles with a 13.55V float voltage. Built-in protection guards against battery over-charge, reverse connection, and excessive discharge with a 10.8V cut-off threshold.

Comprehensive system safety protections

Solar inputs are protected against backflow and reverse polarity, while all DC and USB outputs feature short-circuit, over-current, and over-temperature safety circuits. OUT1, USB1, and USB2 share a combined continuous capacity of 5A (25W) with an 8A peak.

Downloads & documentation

• Product wiki (DFRobot)