This design is based on a Linear LT8490/LT8491 High Voltage, High Current Buck-Boost Battery Charge Controller with Maximum Power Point Tracking (MPPT).

Most PV solar regulators are buck regulators and require the PV panel voltage to be above the battery voltage. This design uses a buck-boost topology and allows the PV solar voltage to be above, below or equal to the battery voltage.

The IC itself allows for a PV panel voltage in the range of 6V to 80V. Please note this design uses 63V input capacitors, and these would need to be switched out for panel voltages exceeding approximately 50V. The low voltage shutdown is configured for 5V.

The LT8490/LT8491 will charge both Lead Acid and Lithium Batteries between 1.3V and 80V. Again, please observe output capacitor voltage ratings – The output caps in this design are rated at 35V but can be replaced with higher voltage ratings, if required.

The MPPT (Perturb and Observe) and charging algorithms are incorporated into the LT8490/LT8491 - hence no programing is required.

The LT8491 is a more recent version of its predecessor and adds telemetry and configuration over an I2C interface. Telemetry data includes voltage/current/power in, voltage/current/power out, efficiency, battery temperature and various charging status parameters.