If by maintenance you mean not needing to watch and refill water levels I agree AGM can be a good choice, but only with the right charging conditions as the others have said. Our house bank AGMs lived 8 seasons with no issues, and our engine and thruster batteries are still going strong in season 12. The only “maintenance” I do is to clean the posts once a year. Having said that ours live very sheltered lives. They sit on a shore charger all spring, summer, and fall, and are left disconnected for the winter. We do lots of day sails that bring them down to no worse than 80% SOC, and a handful of nights anchored out per year where they go closer to 50%.