Deep-cycle batteries utilise an AGM or Lithium technology and are suitable for applications requiring regular discharge and charging. In AGM batteries this could be as low as 50% of the battery capacity or up to 100% in lithium batteries. Sealed Performance Batteries has a number of deep-cycle batteries that are suitable for cycling in both AGM and lithium. This includes the Power-Sonic, Zeal and Invicta lithium ranges as well as some in the Energizer and ACDelco ranges. Depth of discharges can vary depending on the battery but for most AGM batteries it will be no more than 50% and lithium can go as low as 100% without damaging the battery. If you are unsure which battery please contact our customer support team, they will be able to point you in the right direction and find the right deep-cycle battery for your application.