Ideally, your battery bank should only be made up of a single series of cells. The more cells that are included, the higher the chance of there being random defects. There’s also a greater chance of losing equalization, resulting in cells failing prematurely.
If you can’t stick to just a single series of cells in your battery bank, limit it to three parallel battery strings.
If you’re using a solar panel or wind power system, you should make sure that your battery bank is big enough to carry six to ten days of load.
This ensures:
You’ll always have a nice back-up supply of power.
And you’ll also be able to use your batteries a little more gently so you don’t have to consistently drain them.