The Rolls Surrette S2-590AGM (S2590AGM) Deep Cycle Battery features a high cycle life without the need for maintenance. The AGM technology (Absorbed Glass-Mat) keeps the electrolyte (Acid) contained in the glass mats allowing the S2-590AGM (S2590AGM) to not expel any liquids even under severe overcharge. The S2-590AGM (S2590AGM) is a non-hazardous battery resulting in lower shipping costs and can also be shipped via air. AGM batteries have an extremely low internal resistance giving them a very low self-discharge rate. The S2-590AGM (S2590AGM) is a 2 volt battery with a capacity of 590 Amp Hrs. @ 100 Hr. rate or 550 Amp Hrs @ 20 Hr. rate. The terminals are brass auto posts with top threaded inserts. Warranty is 5 years (First 24 months free replacement, next 36 months prorated). For a single string of 590 Amp Hrs. @100 Hr rate, you will need 6 of the S2-590AGM (S2590AGM) for a 12-volt system, 12 of the S2-590AGM (S2590AGM) for a 24-volt system and 24 of the S2-590AGM (S2590AGM) for a 48-volt system. Each additional string will multiply the Amp Hrs.