The Best Places To Put Batteries On Your Boat

Marine batteries are an essential component of any boat, providing power to start the engine and run electronics. There are several types of marine batteries, each serving a different purpose, such as starting (cranking) batteries, deep-cycle batteries, and dual-purpose batteries. Installing a marine battery can be a straightforward process, similar to installing a car battery. However, it is important to take necessary precautions when working with electrical equipment. Before installing a new battery, it is crucial to have the appropriate tools and safety gear, such as wrenches, safety glasses, and gloves. The process involves locating the battery, switching off the marine battery switch, and disconnecting the battery cables. When installing the new battery, it is important to ensure proper alignment and secure connections. Regular maintenance and care, such as cleaning and monitoring battery life, are crucial to prolonging the life of marine batteries.

Battery type: cranking, deep-cycle, or dual-purpose

Marine batteries are designed to power everything from a boat's engine to electronics and accessories. There are three main types of marine batteries, each serving a different purpose: cranking, deep-cycle, and dual-purpose.

Cranking Batteries

Cranking batteries, also known as starting batteries, are designed to deliver quick bursts of energy to start a boat's engine. They are not intended for extended or continuous use. Cranking batteries have many thin plates, maximising the plate surface area inside the battery, which makes it easier to provide the necessary power to start a marine vessel.

Deep-Cycle Batteries

Deep-cycle batteries are built to provide consistent power over long periods, making them ideal for running electronics, appliances, and trolling motors. They have fewer, thicker plates, allowing them to provide continuous power output safely. Deep-cycle batteries can be entirely drained and recharged frequently, and they are less prone to overheating.

Dual-Purpose Batteries

Dual-purpose batteries aim to balance the characteristics of both cranking and deep-cycle batteries. They can deliver the high burst of power needed to start an engine and provide a moderate amount of sustained power for electronics and accessories. While dual-purpose batteries are less efficient than specialised batteries, they can be sufficient for smaller boats with less demanding engines.

Choosing the Right Battery

The choice between cranking, deep-cycle, and dual-purpose batteries depends on the boat's size, power needs, and intended usage. Larger boats with sophisticated systems or high power requirements may need separate starting and deep-cycle batteries or a dual-purpose battery. It is important to consider the boat's specific design and stick with the recommended battery type to avoid failure or other issues.

Battery chemistry: flooded lead acid, gel, AGM, or lithium iron phosphate

Marine batteries are responsible for any electrical process on your boat, from the trolling motor to GPS, radios, and more. They are designed to supply higher bursts of energy and withstand the forces of the water.

There are three main types of boat batteries: flooded, sealed, and lithium. Each has its own pros and cons, and it's important to choose the right one for your boat.

Flooded Lead-Acid Batteries

Flooded lead-acid batteries, also known as "wet cell" batteries, are the most common type of deep-cycle battery. They are the most cost-effective option upfront, but they require periodic inspection and maintenance due to containing free liquid and gas. They emit hydrogen gas, which can be explosive and corrosive in extreme cases, making maintenance more difficult and dangerous. Flooded batteries are also more susceptible to extreme climates and can be damaged by rapid, forceful movements.

Gel Batteries

Gel batteries are filled with an electrolyte similar to wet-cell batteries, but the liquid is turned into a gel. This eliminates the need to replenish the cells with water. They are generally maintenance-free, have a greater resistance to boat vibrations, and can be stored over winter without frequent recharging. However, they are more expensive than wet-cell batteries and require special equipment to charge.

AGM (Absorbed Glass Mat) Batteries

AGM batteries provide superior power and are resistant to vibration, can be installed at any angle, and are sealed, non-spillable, and maintenance-free. They can last up to twice as long as standard flooded batteries, making them an efficient and strong choice. Most AGM batteries have a lifespan of around 500 cycles. They are generally more expensive due to high manufacturing costs and are sensitive to overcharging and high voltages, requiring specific chargers.

Lithium-Ion Batteries

Lithium batteries are a newer option, offering high performance and a rising choice for boaters worldwide. They often perform better and last longer than lead-acid batteries, with lifespans of up to 2,000 cycles. They have multiple voltage output options and are smaller and significantly lighter than other alternatives, which can greatly impact boat performance. However, they are the most expensive option, costing four to five times more than lead-acid batteries. They also require temperature regulation in freezing conditions.

Battery installation: locating and securing the battery

The process of installing a marine battery is usually simple, but it's important to be aware of the potential risks involved when working with electrical equipment. Before you begin, you'll need a new boat battery and a battery box to protect the battery from the elements. You'll also need two wrenches of different sizes to remove the existing battery connections and install the new one.

Locating the Battery

First, locate the battery within your boat and switch the marine battery switch to "off". Disconnect the battery cables, starting with the negative cable, then the positive cable. Gently lift the battery out of its box or compartment and place it out of the way, ensuring that the cables are completely clear.

Installing the New Battery

With the old battery removed, check that the terminals of the new battery are lined up with the cables. Lift the new battery into the battery box or compartment. Before reconnecting the cables, grease the terminals with a small amount of Vaseline to ensure a strong, reliable connection.

Reconnect the cables, beginning with the positive terminal, then the negative. Ensure that any loose cable is secured out of the way. Using your wrench, make sure the cables are firmly attached to the battery terminals, tightening them softly but firmly.

Once the cables are attached, place the lid back on the battery box or close the lid of the compartment.

Securing the Battery

It's important to secure the battery so that it doesn't move around. The American Boat and Yacht Council (ABYC) recommends that batteries are secured so that there is no more than one inch of movement in any direction. Pre-manufactured, acid-proof battery boxes are available in various sizes and are the best way to safely anchor the batteries.

If you're using more than one battery, you may need more than one box. Home-built battery boxes must be constructed from marine-grade plywood, covered inside and out with fibreglass cloth saturated with epoxy, and secure enough to withstand a capsize.

Do not mount batteries directly above or below a fuel tank, fuel line, or filter, or directly below battery chargers or inverters.

Testing the Battery

Switch the marine battery power switch to "on". To test the battery, switch on any electronic device that depends on the battery as a power source, such as navigational equipment. If the device works, the battery is properly connected. If you're testing a starting battery, you can also attempt to start your boat's motor to check that the battery is functioning correctly.

Battery maintenance: cleaning, charging, and storage

Marine batteries are the heart of a boat's electrical system, so it's crucial to keep them well-maintained. Here are some detailed tips for cleaning, charging, and storing your boat's battery to ensure optimal performance and longevity.

Cleaning

• Prepare a cleaning solution: Mix baking soda with distilled water. Baking soda neutralises battery acid, and distilled water is recommended over tap water to avoid introducing minerals that could harm the battery.
• Disconnect the battery: Turn off the marine battery switch or disconnect the battery cables, starting with the negative cable, to ensure safety during maintenance.
• Wipe down the battery: Use a cloth to remove dust and debris from the battery case, making it look pristine.
• Clean the terminals: Apply the baking soda solution to the terminals to eliminate corrosive sulfate deposits. This ensures efficient power and voltage transfer, extending the life of your battery.

Charging

• Avoid overcharging: Overcharging can damage the battery and reduce its lifespan. Only use a charger designed for marine batteries, and follow the manufacturer's instructions for proper charging voltages and procedures.
• Use a trickle charger: When your boat is not in use for extended periods, consider using a trickle charger to maintain battery health and keep it charged.
• Store fully charged: Before off-season storage, ensure your batteries are fully charged. A partially charged battery is more likely to freeze.
• Prevent deep discharges: Aim to recharge your battery when the state of charge drops below 50%. Storing your battery fully charged also helps prevent self-discharge.
• Monitor battery voltage: Use a voltmeter to regularly check the battery's voltage and ensure it remains within the optimal range.
• Equalize the battery: Consider using a battery conditioner to equalize the battery, which involves a controlled overcharge to break down sulfate deposits on the battery plates, extending the battery's lifespan.

Storage

• Use a battery box: Secure the battery in an acid-proof box or tray to contain spills and protect it from physical damage.
• Store in a cool, dry place: Keep the battery in a well-ventilated area, away from direct sunlight, and protect it from extreme temperature changes.
• Prevent overcharging: Use a reliable battery charger that stops charging once the battery is full to avoid overcharging and damaging the battery plates.
• Regularly charge during storage: Periodically charge stored batteries, especially during prolonged periods of inactivity, to maintain their charge level and prevent self-discharge.

Battery disposal: recycling and safe disposal methods

Marine batteries are essential for boating, powering everything from the engine to electronics and accessories. They are also designed to be 95% recyclable, so it is important to dispose of them properly.

In general, batteries contain reactive chemicals and metals that generate electrical energy. These valuable materials can be recycled to protect the environment. However, if thrown away, they can be harmful to the environment. Some batteries contain toxic metals such as mercury, lead, cadmium, nickel, and silver, which can pose a threat to human health or the environment if not managed properly.

In many states, it is illegal to dispose of a marine or automotive battery in the trash. Batteries should be recycled at a battery recycling center or returned to a marine supply store. If you’re not sure where to dispose of old batteries in your area, check Call2Recycle, which has a list of battery recycling centers sorted by state and ZIP code. Many local districts also host collection events for residents to drop off batteries.

If recycling is not an option in your area, contact the manufacturer or retailer for advice on safe disposal. Some battery manufacturers and recycling facilities also have mail-in programs.

When disposing of batteries, it is important to take precautions to prevent fires and other hazards. Tape over the battery terminals or place batteries in separate plastic bags to prevent short circuits and potential fire hazards.

In addition to proper disposal, it is also important to maintain and care for your marine batteries to extend their lifespan. Keep them clean and free of dirt or corrosion. Store them in a cool, climate-controlled environment when not in use. Regularly check the battery terminal connections to ensure they are snug and corrosion-free.

Frequently asked questions