Solar energy harvesting is on the rise, but the main drawback of solar energy harvesting is that it can only generate electricity when the sun is present in the sky. To overcome this issue, batteries are used to store the energy which can be used at a later time when solar irradiance is insufficient to generate electricity.
The reference design from ADI is of a high-efficiency Li-Ion battery charger with Maximum Power Point Tracking (MPPT) and TELEMETRY. The design is up to 97% efficient and can accept various power sources including Solar Panels of up to 200W. The reference design features a buck-boost configuration, therefore, it can take input voltage below, above, or equal to the battery voltage from 17V to 54V and features a USB to I2C controller for enabling communication. The Reference design is highly programmable and is suitable to be used as a Solar charger or a stand-alone charger for multiple cell chemistries which includes Li-Ion, LiPo, SLA, etc.
You can download the datasheet of this reference design by clicking here.
The on-chip logic of LT8491 IC enables true MPPT function which continuously tracks the maximum power point at all times. In order to select the maximum value on the power curve, it periodically sweeps the input panel voltage.
The LT8491 includes a slave I2C compatible interface for digital control of the charger settings and digital readouts of charger telemetry and status. The module is compatible with an MS Windows-Based Graphical User Interface (GUI) application called “simpleLT8491” which enables the user to monitor and control the telemetry and status data of the charger and battery pack in real-time. The DC2703A-A-KIT is capable of supporting higher current and voltage for different cell configurations by replacing the input side MOSFETs and capacitors with ones with higher ratings.
The core circuitry of the LT8491 MPPT charger is shown below:
The circuitry of LT8491 MPPT charger
The Schematics can be downloaded by clicking here.
Features of the Reference Design
• Operation from Solar Panel or DC Supply
• VIN Range: 17V to 54V
• VBAT Range: 1.3V to 80V
• Single Inductor Allows VIN Above, Below, or Equal to VBAT
• Automatic MPPT for Solar Powered Charging
• Automatic Temperature Compensation
• I2C Telemetry and Configuration
• Remote sensing of battery voltage
The company provides various resources such as Schematics, Gerber files, User Interface firmware, etc. which can be downloaded by clicking on this link.