Use series when you need higher voltage and use parallel when you need more capacity (longer run time); combining both lets you tailor voltage and amp-hour capacity to match your equipment. . In every energy storage system (ESS), how batteries are connected— in series or in parallel —plays a critical role in determining system performance, safety, and scalability. This fundamental configuration choice directly affects voltage, current, capacity, and overall reliability. Understanding. . Understanding batteries in series vs parallel is crucial for building efficient, reliable energy storage systems. Let's explore everything you need to know! What is Wiring in Series? When wiring batteries in series, you connect the positive terminal of one battery to the negative terminal of the. . Battery pack configurations determine how much power a battery can provide and for how long. in series, 2. series-parallel combinations.