Building battery packs for various, significantly different applications, is often complex and risky. Detailed cell and pack modeling and simulation tools, along with existing and predicted power and energy profiles significantly reduce the risk of designing and integrating a new pack for new applications on the battlefield. This paper will discuss a number of modeling and simulation techniques, using case studies as examples, that ensure a battery pack, when integrated to the application, will meet the predicted performance goals and specifications. Actual data will also be shown to validate these techniques that significantly reduce development time and risk when providing power to the Warfighter.