We have investigated to determine the technical feasibility of re-purposing lithium-ion batteries for use in low-cost transportable renewable energy storage systems. In addition, the benefits of re-purposing these battery packs will be analyzed. When the Li-ion batteries in HEVs or PHEVs reach the end of their service life, recycling or re-purposing lithium-ion batteries poses a special challenge for automobile companies throughout California and the USA. Therefore, it is much more economical to first re-purpose lithium-ion batteries for transportable/renewable energy storage applications. Once the batteries have been consumed, if they cannot be re-purposed, they can still be recycled to their constituent ingredients.