Recumbent tandem with dual motors and automatic tilting of solar panels

A solar-powered tandem built on the basis of an Azub Twin, equipped with two motors: a Grin all-axle direct-drive motor at the rear for regenerative braking and a geared eZee One motor at the front to assist on climbs or when carrying a heavy load. Each motor has its own PhaseRunner controller and is controlled by the rear motor’s torque sensor via a dual WP8 splitter connected to the Cycle Analyst.

They are powered by a DIY battery pack made up of 14S x 10P 21700 cells instead of the 18650 cells typically found in bike battery packs (52V, 53Ah). Its peak current of 80A allows it to power both motors simultaneously.

Two solar panels of 235W each are automatically oriented using a linear actuator. Instead of using light sensors, a 9D sensor featuring a magnetometer, accelerometer, and gyroscope was used to determine the bike’s orientation. Based on the time and position obtained via GPS, a program on an ESP32 board calculates the sun’s exact position and the optimal orientation of the panels. Rotation occurs only if it results in a sufficient power gain.