The reading I did years ago stressed that you should definitely cycle batteries to as close as Zero as possible, but if you want to do long-term storage keep them at 40%. Seems like there is a lot of myth around how batteries work and proper practice. A unified resource on this would be great!
Layman Science Wizard recently explained to me that pumping water up into a storage tower (using solar-based energy) and then using the gravity-drop to generate electricity again (when the sun is gone) was also very effective. A natural battery of sorts. No batteries to wear out, neither. Feasible?