Battery Charging System For Nanosatellite

Abstract

Nanosatellite is a small satellite weighing less than 10 g. One type of nanosatellite is a 1U CubeSat with a size (10×10×10) cm3. When orbiting the Earth, nanosatellites have two conditions, namely light time and eclipse time. Eclipse time is when the satellite does not get enough sunlight, while the primary energy resource of nanosatellite is sunlight. This final project will design a nanosatellite power supply with a battery charging and discharging system using a Battery charger IC. IC Battery charger has a power path feature that determines the power source of satellite power during light and eclipse times. The battery charging system is equipped with a float Voltage feature to keep the battery at its maximum capacity, temperature monitoring to maintain battery temperature and a minimum input Voltage to avoid Voltage drops. The discharge system features under Voltage protection to keep the battery Voltage at a safe level by reducing the bias current to <0.1 μA. by using float Voltage, temperature monitoring, minimum input Voltage and under Voltage protection. This system is expected to increase efficiency and keep the lifetime of the battery. The result of this project is that the battery can be charged with 1.05 Watt on minimum, where only one solar panel’s side is exposed to sunlight, 2.52 Watt when two sides are exposed, and 4.74 Watt when three sides are exposed to sunlight. Nanosatellite must turn off one of its modules when it’s minimum power. At the same time, nanosatellites can save 1.37 Watt when two panels work and 3.59 Watt when three panels work.