How do you maintain solar batteries?

If you want longer battery life, is in solar batteries required:

- Check the acid level at least every 6 months

- All batteries must not be under 10.8 - 11V, because the battery could be empty , it can be even destroyed.

- For open batteries (ordinary solar cyclically-acid batteries); no cell may not be empty -> Needs occasional control and filling  electrolytes in the battery