3 Types of Batteries Used for Powering Boats

If you’re considering purchasing a boat, whether for pleasure or as a commercial venture, you should know the basics of how they operate, especially if you’ve never owned one before. It’s important to know what type of battery to purchase if you need to replace one. There are three different types of batteries used on boats:

  • Starting Batteries
  • Deep Cycle Batteries
  • Dual-Purpose Batteries

When choosing a battery, you need to know the purpose of it.

Starting Batteries

The name of these batteries imply what they do: they are used to turn over the crank and start the boat. Starting batteries consist of several thin plates that provide extra surface area to generate high powered bursts of current required to start a boat. They can generate anywhere from 75 to 400 amperes for 5 to 15 seconds. The starting battery is automatically recharged by the boat’s alternator and as long as the alternator is not malfunctioning, your boat will be ready for restart after it is shut down.

Deep Cycle Batteries

After the starting battery has provided the necessary power to start your boat, anything else you need power for on the boat will run off the deep cycle battery. However, if power is provided by other sources, such as solar panels, a shore power charger, or an alternator, then the deep cycle batteries will stay dormant until they are needed.

A deep cycle battery is made with thicker plates to provide heavier discharges over longer periods of time. In addition, the plates are built with more antimony, which is a metalloid, than starting batteries. When selecting the best deep cycle marine battery for your boat, you should choose one three to four sizes larger than the anticipated amount of energy it will use between each recharge cycle.

Dual-Purpose Batteries

You will usually get better performance from a deep cycle or starting battery, but a dual-purpose battery can be used for some applications. They have thicker, larger plates that are made with more antimony than starting batteries and they can tolerate deeper discharges. They are mainly used for smaller craft, such as runabouts or small powerboats, in which the battery both starts the boat and provides house power.

Two dual-purpose batteries can be used to provide house and starting power for sailboats or they can be used on boats with only one battery bank. The dual-purpose battery will be a better choice than starting batteries, because they can provide longer, more reliable service. For larger boats, a deep cycle battery should be bought, because dual-purpose batteries don’t have the same storage capacity.

Battery maintenance is just as important for your boat as it is for your automobile and will help prolong the battery’s life. Occasionally check the connections to make sure the cables are not loose and check for corrosion on the posts. If you see any build-up on the battery posts, remove the cables and clean both the posts and cable connections with a wire brush. Then replace the cables, tighten them, and start the boat.