Marine Batteries 101: Back to Basics

Power - by Joe Weber - updated on 3/4/2024

Sun on your face, wind in your hair, fishing rod in your hand… the day could not be any better. Nothing ruins a perfect day on the water like a surprise dead battery. But fear not! This quick guide will give you a brief overview of marine batteries, how to take care of them and help you choose the right one for your boat.

From cranking to deep-cycle, we'll make sure you understand the basics and leave the dock with confidence. So, grab your virtual life jacket and dive in - smooth sailing awaits!

What Are Marine Batteries?

Marine batteries are like the unsung heroes of your boat, powering everything from starting the engine to running your fishfinder and other accessories. Unlike car batteries, marine batteries are built tougher for the waves, vibrations, and deep discharges that come with life on the water. Think of them as your reliable first mate, always keeping your boating adventures worry-free!

Types of Marine Batteries

Marine batteries come in a few different varieties depending on what you are looking to power on your boat.

• Starting Batteries (Cranking Batteries): Deliver a short, powerful burst of energy to crank your boat's engine. Similar to car batteries, they have high Cold Cranking Amps (CCA) ratings, indicating their ability to crank your engine, even in cold weather.
• Deep Cycle Batteries: Designed for sustained power supply to your boat's electrical systems, like fishfinders, trolling motors, and lights. They have deep reserves and can be discharged and recharged repeatedly without damage. They have high Amp-hour (Ah) ratings, indicating their total energy storage capacity.
• Dual-Purpose Batteries: Offers two batteries in one with starting and deep cycle capabilities, great for smaller boats with limited space for extra batteries. They provide reliable cranking power and moderate deep-cycle performance for accessories.

Marine Battery Chemistries

When it comes to batteries for your boat, there are three main chemistries to choose from, each with its own set of pros and cons:

1. Flooded Lead Acid: The traditional and most affordable option. They offer high cranking power but require regular maintenance, mainly checking electrolyte levels and removing corrosion and can be quite heavy.

   A great basic battery choice is in the Duracell Ultra Flooded line. They have options that range from starting to deep-cycle. They are a fantastic option that provides powerful and reliable energy with a long service life. Best used in boats with moderate power demands.

2. AGM (Absorbed Glass Mat): A great upgrade to flooded batteries, AGM batteries require no watering and are spill-proof, making them ideal for confined spaces and can be mounted in many positions. They offer great cranking power and moderate deep cycle performance but are generally more expensive than flooded batteries.

   If you are looking for an upgrade for your boat with lots of power demands but still want strong starting power, look no further than the dual-purpose X2Power AGM battery. Get the ultimate performance available with higher CCAs, more durable plates and 3 times the life of flooded batteries.

3. Lithium Iron Phosphate (LiFePO4): The latest and most advanced option. Specifically designed for deep-cycling, they offer exceptional deep-cycle performance, lifespan and are incredibly lightweight. However, they do come at a higher initial price point but last incredibly long.

   If you are looking for the pinnacle of deep-cycle performance for your heavy-use fishing boats, tour boats, professional angling and more, then the X2Power Lithium deep-cycle battery is the best battery for you. With 10 times the life of flooded deep-cycle batteries, half the weight and built-in Bluetooth monitoring, these batteries are a next-level upgrade for your boat.

   See below for an easy-to-follow chart of the pros and cons of the different chemistries.

Chemistry	Pros	Cons
Flooded Lead Acid	Affordable, good cranking power, proven reliability	Requires maintenance, heavy, limited mounting options
AGM	Maintenance-free, spill-proof, good deep cycle power, very durable	More expensive than flooded, more sensitive to overcharging, heavy
Lithium Iron Phosphate	Highest energy storage and deep cycle performance, long lifespan, lightweight	High initial cost, deep-cycle only, sensitive charging requirements

Ultimately, the best chemistry for your boat battery depends on your specific needs and budget. Consider factors like your boat size, engine type, power demands, and how often you use your boat when making your decision.

How to Choose the Right Marine Battery

Choosing the right marine battery is crucial for smooth sailing and avoiding unexpected dead-on-the-water or dead NOT-on-the-water situations. Here's some quick tips to help you navigate the options:

• Consider the size of your boat and the size of your motor. Smaller boats may be able to get away with only a single starting or dual-purpose battery while larger boats or boats that are used for fishing may require multiple batteries to start the engine and operate all of the fishing equipment.
• How many electronics do you run? Boats that have a lot of power demands will need more powerful batteries or separate deep-cycle batteries.
• Think about the temperature. If you operate a fishing boat that hits the water in early spring or are just one of those who can't wait for the weather to heat up, you might want to consider a battery that works better with extreme temperature variations.

How Do You Maintain Marine Batteries?

Keep your batteries happy and healthy all year by following a few simple steps.

1. Routinely check fluid levels (flooded lead-acid batteries)
   Regularly check and top up the water level in your Flooded Deep Cycle battery cells with distilled water, never use tap or filtered water. Only add enough to cover the plates, and remember, consistent upkeep is key to keeping the battery healthy.
2. Clean the battery
   Think of cleaning your battery like giving it a much-needed spa day. Removing grime and corrosion helps it perform better and last longer, keeping your boating adventures worry-free. A terminal protection kit is a handy item to keep in your toolbox.
3. Charge deep-cycle batteries after each use
   Letting your marine battery sit partially discharged is like keeping your car in first gear - It's not good for its health! Recharge it as soon as possible after each use to maximize its lifespan.
4. Use a battery maintainer
   A battery maintainer is essentially an automatic babysitter for your battery. It keeps it topped up safely while you're not using it, preventing deep discharges and overcharging while maximizing its lifespan so it's ready to go when you need it.

How Do You Store Marine Batteries?

Storing your boat battery properly is crucial to ensure its longevity and avoid any unpleasant surprises come spring. Here's a short list of tips to store your batteries the right way for a ready-to-go battery in the spring.

1. Charge it: Before storing, give your battery a full charge using a battery charger specifically designed for your battery type (AGM, flooded lead-acid, etc.).
2. Disconnect the battery: Once fully charged, disconnect the battery from the boat's electrical system (if you haven't already) to prevent parasitic draws that can slowly discharge the battery over time.
3. Clean it: Wipe down the battery exterior with a damp cloth to remove any dirt and grime. Use a terminal cleaner and wire brush to remove any corrosion and clean the terminals.
4. Keep it in a cool, dry place: Avoid storing it in freezing temperatures, relentless heat, direct sunlight, or areas with high humidity. A garage or shed can be a suitable option.
5. Connect it to a maintainer: Battery maintainers automatically keep the battery's charge at an optimal level, preventing sulfation and extending its lifespan.
6. Check it regularly: For flooded lead-acid batteries, check the electrolyte level every few months and add distilled water if necessary to keep the plates submerged. If you don't have a maintainer, check the charge every couple of months and charge the battery if the charge drops below optimal levels.

For more information on properly storing your marine batteries, take a minute to read another one of our helpful blog articles "Storing Your Boat Battery in the Winter".

How Long Do Marine Batteries Last?

Well-maintained marine batteries can boast lifespans of 4-6 years but remember, longevity isn't guaranteed, it's a reward. By following the tips and tricks we've shared in this post, you'll be equipping your battery for a long and healthy life on and off the water.

From choosing the right type to proper storage practices, your proactive care will ensure your boat never gets left stranded due to a dead battery. Failure to maintain or properly store your batteries could result in you replacing batteries much earlier than you need to.

Batteries Plus Is Here to Help

We know that questions and concerns will always come up. That's what the battery experts at your friendly neighborhood Batteries Plus are here for. Stop by, give us a call or visit our blog and website for all the help you need with your marine batteries. From helping you test your batteries to picking out the best ones for your boat, we've got you covered.