Lithium boat batteries claim to turn all these performance expectations on their head. They claim discharge capacities of nearly 100% even at 100A discharge, and cycle lives of 2000+ at similar discharge currents and 80% DoD. The aim of our exercise was to put these claims to the test. To ensure fairness across. In simple terms, all the batteries on test delivered within 3-4Ah of their claimed maximum outputs at 25A and 100A, with some even achieving this at 150A. Also as the lithium battery discharges, its voltage remains nearly constant,. So is lithium for you? Well, being realistic, if you only use your boat 10-20 times a year, and just run lights and navigation equipment, then lead-acid. We normally try to give a suggested Best Buy in our tests, but in this case there is no one clear winner, and no single test measurement that we could fairly apply. For instance the Sterlings.