Lead-acid batteries are the oldest and today the most widespread technology used for energy storage. Used for starting the engines of cars, motorcycles, boats, etc. but also for millions and millions of off-grid and on-grid photovoltaic systems. This type of battery has the enormous advantage of being extremely reliable. AGM technology Inside the AGM batteries there is a valve that automatically renews the energy production without having to fill the battery with the addition of acid.If the abbreviation AGM (Absorbed Glass Mat) is shown on the battery it means that inside there are fiberglass plates that absorb and retain acid. In normal state, lead AGM batteries are equipped with a gas recombination system inside. The valves therefore have the task of releasing gas in the event of an overload. The AGM plates therefore make it possible to reduce the production of gas by transforming it into water and redistributing it in the internal circuit so that it produces current. AGM technology therefore allows to have a hermetic battery without any possible leakage. Should the battery fall, the acid will not leak. AGM batteries also do not require any type of maintenance: unlike lead-acid batteries, they do not require regular additions of electrolyte.