An off-grid solar system is designed for the power needs of mid-to-large size homes. Unlike a grid-tie solar system, off-grid systems have no connection with the utility grid and must make all the electricity necessary for your home. Off-grid solar systems operate from the stored energy in a battery bank. Solar panels are used to keep the battery bank charged. Your off-grid solar system has to be sized properly to support your daily power needs and replace the stored energy pulled from the battery bank.