Concept of modularity is fast picking up in small satellites due to the ever-increasing user demands for cartographic applications at cadastral level, urban and rural management, coastal land use and regulation, utilities mapping and development and various other remote sensing application. Modularity will enhance the ability to launch a new satellite within few weeks of user's request. Thermal design of small class of satellites is quite challenging due to its space and power constrains. To meet this challenge the thermal design has to be simple and robust. Traditionally, the TCS is vigorously designed, analysed and optimised for every satellite mission. The next generation satellites demand a more modular thermal control system to meet the wide range of mission requirements. With various boundary conditions and flight uncertainties it is a must to account these factors. In the satellite, temperature requirements of battery are typically narrower that other surrounding elements. This paper describes the modular approach of thermal design for batteries in small class of low Earth orbit satellites suitable for various inclination orbit