Buying Guide: Boat & Marine Batteries

Deep Cycle Flooded, AGM & Lithium Batteries for Boating

Deep-cycle marine batteries are engineered for long-lasting, reliable power, making them ideal for fishing boats, kayaks, and watercraft relying on trolling motors, live well pumps, and fish finders. Unlike standard starting batteries, they feature a design with fewer, thicker lead plates that allows them to withstand high temperatures and be deeply drained and recharged many times. This unique construction ensures they can deliver high electrical currents at a consistent rate over extended periods, giving you the durable energy needed to power all of your onboard applications.

Shop Deep Cycle Marine Batteries

Dual Purpose Marine Batteries

Sitting right at the mid-point between starting and deep-cycle models, dual-purpose marine batteries offer the best of both worlds by providing the strong cranking power needed to start your engine alongside the cycling capacity to run your accessories smoothly. Available in flooded lead-acid, Platinum AGM, and Ultimate AGM designs, these versatile batteries are an excellent, cost-effective solution if you are looking to save both money and onboard space. By replacing a traditional two-battery setup with just one dual-purpose unit, you can reliably power your boat's engine and all of your electronic applications at the same time.

Shop Dual Purpose Marine Batteries

Starting Batteries for Boats

Much like a car battery, a boat starting battery is engineered to deliver a short, powerful burst of cranking amps to turn over your engine when you turn the key. Its design utilizes thinner, wider plates to maximize surface area and deliver these high initial currents, which are then quickly replenished once the engine's alternator kicks in. While this setup is perfect for powering inboard/outboard motors, marine lights, and radio communications, it strictly limits the battery's depth of discharge. Because they can only be drained by a small percentage without causing damage, starting batteries should never be relied upon to run heavy onboard electronics or power a trolling motor.

Shop Starting Marine Batteries

Batteries Plus carries three different marine battery chemistries. The best one for you will depend on how hard you run your boat, your boat’s power demands and what accessories you have attached to it. Always select the battery that suits your boat’s needs.

Flooded Boat Batteries

Often called "wet cell" batteries, flooded batteries use a liquid sulfuric acid electrolyte to fill the case and cover the lead plates. This is where the term "flooded" comes from. Flooded batteries are not as rugged or vibration-resistant as other chemistries and must be mounted vertically to prevent electrolyte spillage. They self-discharge slightly more than other batteries, so you must ensure you charge them periodically in the off-season to keep them healthy.

They offer the lowest initial cost of all the batteries but require routine maintenance to ensure a long life. With proper care, flooded batteries can last several hundred charge cycles.

AGM Boat Batteries

Every year, more and more boaters are making the switch from flooded to AGM batteries to power their boat. AGM, short for Absorbed Glass Mat, batteries use a fine fiberglass mat, tightly packed in between the lead plates and then soaked in a sulfuric acid electrolyte solution. The fiberglass mat provides much more durability than a loose-flowing electrolyte.

AGM batteries have a lower internal resistance, allowing them to provide greater starting power as well as better charge acceptance. They can charge twice as fast as other lead-acid batteries. AGM batteries come in dual-purpose varieties that can handle both starting and deep-cycle operations.

They also feature longer lifespans than flooded batteries, have a lower self-discharge rate in storage and are virtually maintenance-free.

Lithium Marine Batteries

Lithium Iron Phosphate (LiFeO4) batteries are the newest and most advanced marine batteries on the market today. X2Power and Energizer Industrial Lithium (LiFePO4) marine batteries are for deep-cycle applications only and are not to be used as starting batteries.

Boasting the highest energy density of all other marine batteries, LiFePO4 batteries pack a tremendous amount of power in a lightweight package. When looking at a BCI Group 24M battery, the AGM version is 57.7 pounds. Lithium? 20.8 lbs. In addition to the weight savings, lithium batteries have 10x the life of lead-acid batteries, charge 4x faster than AGM and provide the best deep-cycle performance money can buy.

LiFePO4 batteries do have a higher initial cost than most batteries. However, with their long lives, you will no longer have to replace batteries as often, saving money in the long run.

10 Year, 2000 Cycle Limited Warranty on X2Power Lithium Batteries With Bluetooth

Shop X2Power Lithium Batteries Shop X2Power Lithium Chargers

• Get your current battery tested - Have your battery tested for free at Batteries Plus, especially if you've had your boat in storage for a season or more.
• Get yourself a battery box - Use a battery box to minimize the impact of vibration and also to keep your battery secure. (Note that sometimes they're required by law.) An unsecured battery can cause damage to both the battery and your boat.
• Keep connection points clean and electrolyte levels up - If you notice corrosion on your battery terminals, clean it up with a mixture of baking soda and water. If your boat carries a flooded battery, monitor the electrolyte levels before charging or operating your boat.
• Waterproof chargers for the win - Waterproof chargers are perfect for your time on lakes, rivers or other waterways; you'll never find yourself on the water with a dead battery.