Summary: Connecting lithium battery packs in parallel can boost energy storage capacity and system flexibility. However, improper configurations may lead to safety risks. This guide explains the process, safety considerations, and real-world applications – perfect for solar installers, EV enthusiasts, and industrial energy. When multiple batteries are connected in parallel, their individual ampere-hour (Ah) capacities add up, resulting in a higher total capacity. However. Yes, you can mix different capacity lithium batteries, whether a normal 12V 100Ah battery or a Lithium server rack battery. This means two 12V 120Ah batteries wired in parallel will give you only 12V. But increases capacity to 240Ah. The plan below is practical and direct.