Those who have ever experienced a power outage understand the major headaches associated with losing electricity; figuring out how to keep food from spoiling, how to get water, plumbing, lighting, and heating & cooling to name a few. Some of us may have sworn to never have to experience that again, and have investigated a backup generator or battery system only to find them extremely expensive. What if there was a way to own an energy system that serves as a battery backup, reduces utility bills when electricity is available, and has the option to take your home completely off of the grid affordably? This is going to be possible in the near future with the development of Home Energy Storage Systems (HESS) that utilize repurposed automotive cells.

Due to the nature of the battery chemistry, most automotive Lithium-Ion battery packs will need to be replaced after approximately 10 years of service. After that time, they are no longer suitable for their original application, but most will have 80% capacity remaining.

Based on sales over the last few years (and future projections), battery packs will start coming out of vehicles in large quantities around 2020. These cells are suitable for repurposing applications.

Repurposing of cells involves a series of steps by a manufacturing facility to ensure that the cells are in proper working condition and suitable for future use. Though early in its development, the emerging repurposing industry is anticipated to be a multibillion-dollar market by 2020.

Some prior research and discussion have been focused on using these cells for load leveling applications for utility companies. This requires the construction of large-scale systems that would need to be purchased by large utility companies.

Other prior research has focused on removing the pack and controls entirely from the vehicle and retro-fitting it as a home power system. Currently several automotive suppliers are exploring this option.

A small HESS was constructed that could easily have more cells added to power essential appliances in a small home. The current system has the ability to log charging and discharging real-time, and outputs 120 VAC from a 13.2 VDC, 120 Ah source.

This product offers many benefits to consumers, including:

- Enabling consumers to consistently achieve electricity rates of off peak pricing by charging at night and drawing power during on-peak times.

- Serving as a backup power supply.

- Enabling the consumer to easily integrate renewable energy resources.

- Providing energy independence depending on the renewables that are available, the size of the system, and the demand of electricity by the consumer.

Special care was taken when developing the system to ensure that all cells were controlled within the manufacturer’s specifications.

The market for a product such as this becomes much more attractive to consumers since the cells within the battery pack can be purchased at a fraction of the cost of a new cell. This enables these systems to be much more competitively priced than those with new cells.