The first sub-system I am designing for WCTU is the battery system. Originally I had planned on using 6Ah Lithium Ion Batteries however there are several problems(as specified here) with these batteries such as underrated protection circuits and small wire size which cause an unwanted high voltage drop. Luckily, the CMU robotics club received a large shipment of UR18650E Lithium Ion Cells that I have access to. These cells although larger than I would have hoped, are easily obtainable and will meet the project’s design specification. My next task is to design a battery charging circuit.