We need power even when it is not sunny outside
It would be nice if everyday was sunny without a cloud in the sky, but as we know, this is not the case. So we had to plan for the days where our solar panels would not be producing energy. We determined that a battery bank was necessary, with enough storage to last a day or two. Additionally, we selected all of the electrical components (AC/Heat, light fixtures, water pump, etc.) based on their energy consumption... the less energy used the better.