Boating, sailing and other water activities like waterskiing and wakeboarding are some of the great joys of living near a body of water. In order to be sure you have the best experiences every season, it's important for you to maintain your watercraft. This means making sure it has enough power to perform. Just like cars and trucks, boats and other watercraft need regular inspections to make sure they are running properly. If your boat is having power problems, it may be time to replace the battery. Before you do this, however, it is a good idea to learn about the different kinds of marine batteries, so you know which one is right for your boat.
Just like the batteries inside most cars and trucks, marine batteries are typically lead-acid batteries. It's possible to have two kinds of marine batteries for your boat—a starting battery that provides a burst of ignition power and a deep-cycle battery that powers the boat's instruments, lights and radio. The starting battery, after providing power to the engine, will then be recharged by the boat's alternator. The deep cycle battery will provide consistent power at a lower level (and then is recharged when necessary).
AGM (absorbed glass mat) batteries are considered by many to be one of the best kinds of batteries because they can resist vibration and deterioration. Your choice of AGM battery will determine whether you are looking for a deep cycle battery or a starting battery. It's important to note that there are some AGM batteries that have starting functions but do not have deep cycle functions. You should think about what you want to power in your boat, how much power your boat needs and how many batteries you need. There are many boats that need at least four batteries to run everything properly, including the electronic and navigation systems. You will want to look for batteries that can provide weight savings, as well, because you don't want to add too much extra weight to your boat (especially if you have multiple batteries to replace).