What type of battery is required for a battery back-up solar system?
The batteries used in solar systems are similar to car batteries, but are designed for deep cycling use in which a larger percentage of the capacity of the battery is used each night (and then fully charged up each day). Batteries designed for solar projects pose the same risks and demand the same caution in handling and storage as automotive batteries. The fluid in unsealed batteries is highly corrosive, levels should be checked periodically, batteries must be appropriately ventilated, and batteries should be protected from extremely cold weather. In practice we have found that when properly maintained batteries last for about 5-8 years, after which their capacity is significantly diminished.
