Batteries generally function as electricity storage. The process of storing and using electricity is done by charging and discharging. In the Solar Power Generation system the function of the battery is very important to distribute electrical energy from the solar panels to the load. In order for the process of storing and distributing electrical energy to take place normally and optimally, a management system is needed. This paper discusses the work functions and methods of the battery management system (BMS) and compares the types of batteries used in solar power plants from Lithium-Ion (Li-Ion), Lithium-Polymer (Li-Po) ) and Lead Acid (VRLA). so that the operation of the solar power generation system operates more optimally. The function of the Battery Management System (BMS) is to manage the process of charging and discharging the battery, as well as monitoring the condition of the battery, calculating secondary data, reporting battery data, protecting the battery, managing conditions around the battery, and maintaining battery balance. In the Study on Optimization of Battery System Management in Lithium and Lead Acid Batteries at the New Renewable Energy Research Center at the IT PLN