This paper presents results that quantify how the homogenous and heterogeneous parallel interconnection of lithium-ion battery packs affect adversely their cycle-life, and how this problem can be corrected. Laboratory tests and modeling/simulation of two different lithium-ion battery packs are presented that highlight the importance of monitoring and controlling battery packs in parallel. A solution to this problem was designed and a prototype implemented that has the potential to fit within the available space of a commercially available lithium-ion 6T battery pack [1], [2]. This solution controls the sharing of load among heterogeneous and homogeneous lithium-ion 6T batteries with an efficiency of 95% or better, which is anticipated via simulations, to provide an improvement of cycle life of at least 3% for homogeneous and 10% for heterogeneous interconnections. This solution provides additional benefits including terminal voltage regulation and the flexibility to work as an active balancer in series interconnections of 6T battery packs without additional power paths.