Choosing The Right Battery To Power Your Boat's Ignition

Marine batteries are a unique type of battery that powers boats and other watercraft. They are the heart of a boat's electrical system, providing power to start the engine and run electronics. There are three main types of marine batteries: starting (cranking) batteries, deep-cycle batteries, and dual-purpose batteries. Starting batteries deliver quick bursts of energy to start the engine, while deep-cycle batteries provide consistent power over a long period for electronics and appliances. Dual-purpose batteries combine the functions of both starting and deep-cycle batteries but are less efficient than specialised batteries. Marine batteries are designed to withstand the harsh marine environment, including saltwater exposure, high temperatures, and vibrations. They are also more resistant to deep discharge and have a longer lifespan than regular automotive batteries. When choosing a marine battery, factors such as boat size, engine type, onboard electronics usage, and budget should be considered.

Marine batteries: the pros and cons of each type

Marine batteries are an essential part of any boat, powering everything from the engine to onboard electronics. There are several types of marine batteries available, each with its own pros and cons.

Wet Lead Acid Batteries

Also known as "flooded" or "wet cell" batteries, these are the most traditional and affordable type of marine battery. They deliver high loads of power for a short duration, making them ideal for starting the engine.

Pros:

• Cheap and readily available.
• Can be purchased from automotive stores.

Cons:

• Heavy.
• Require regular charging.
• Need good ventilation as they release hydrogen.
• Prone to leaking.
• Useless once they go flat.

Sealed Lead Acid Batteries

Sealed lead acid batteries are a more durable option, often referred to as VRLA (valve-regulated lead acid). They come in two forms: absorbed glass mat (AGM) and gel.

Pros:

• Longer lifespan than wet lead acid.
• Leak-proof.
• Some options are dual-purpose.

Cons:

• More expensive.
• Need regular charging.
• Heavier than wet lead acid.
• Useless once they're flat.

Absorbent Glass Mat (AGM) Batteries

AGM batteries are a type of sealed, deep-cycle battery. They are spill-proof and can withstand more charge/discharge cycles than conventional batteries.

Pros:

• Maintenance-free.
• Greater charge currents, allowing use as a starter.
• Greater charge acceptance for quicker recharge.
• Spill-proof, leak-proof, and submersible.

Cons:

• Require a "smart" charger.
• Sensitive to overcharging.
• Shorter life cycle in deep cycle applications.
• More expensive than wet lead acid.

Gel Batteries

Gel batteries are a type of sealed lead acid battery that uses a thickening agent to create a gel-like substance. They offer a longer lifespan and exceptional cycle life, making them a cost-effective choice.

Pros:

• Sealed, no-maintenance design.
• Longer cycle life than flooded batteries.
• Better tolerance for deep discharges.
• Spill-proof and mountable in any position.

Cons:

• Higher cost compared to flooded or AGM batteries.
• Susceptible to damage from high temperatures.
• Not ideal for engine starting.
• Slower recharge rate.

Lead Carbon Batteries

Lead carbon batteries are an advanced form of VRLA battery, not widely known. They offer a higher life cycle, are leak-proof, and produce less sulfation.

Pros:

• Longer life.
• Less sulfation.
• Less corrosion of the positive plate.

Cons:

• More expensive.
• Larger and heavier than other batteries.
• Cannot be used as a starter motor.

Lithium-ion Batteries

Lithium-ion batteries are the newest and most advanced option, offering a high energy density and longer lifespan.

Pros:

• Long-lasting.
• Can use up to 80% of capacity.
• Small, lightweight, and easy to maintain.

Cons:

• Very expensive.
• Require specific boat adaptations.
• Sensitive to charge requirements.

In summary, when choosing a marine battery, consider your boat's size, engine type, onboard electronics usage, and charging system. Regular maintenance and proper charging are crucial to ensure optimal performance and longevity.

Starting batteries: what to look for

Starting batteries, also known as cranking batteries, are designed to deliver quick bursts of energy to start a boat's engine. When choosing a starting battery, there are several key factors to consider to ensure optimal performance and reliability.

Firstly, it is important to select a battery with sufficient cranking amps (CA) and cold-cranking amps (CCA). CA measures the battery's ability to deliver a burst of power at 32°F (0°C) for 30 seconds, while CCA measures the maximum current the battery can deliver at 0°F (-18°C) under the same conditions. CCA is particularly crucial if you plan to operate your boat in cold weather conditions. As a rule of thumb, gasoline engines require 1 cranking amp per cubic inch, while diesel engines require 2 cranking amps per cubic inch.

Another important consideration is the battery's marine-cranking amps (MCA). MCA measures the battery's power output in marine environments, which are typically warmer than the freezing point. Most boaters should focus on MCA rather than CCA. It is vital to ensure your starting battery has sufficient MCA to guarantee a successful engine start in all conditions.

When choosing a starting battery, it is recommended to consult the engine manufacturer's recommendations. Additionally, consider the size and power requirements of your boat. Larger boats with more sophisticated systems will have different power needs than smaller vessels with minimal electronics.

Starting batteries are not designed for extended, continuous use. If your boat demands continuous power for running electronics, you may need a separate deep-cycle battery or a dual-purpose battery.

It is also essential to consider the battery's reserve capacity (RC). RC indicates how long a battery can provide 25 amps of power before dropping below 10.5 volts. A higher RC means the battery can provide power for a longer duration.

When it comes to battery type, there are several options available, including flooded lead-acid batteries, Absorbed Glass Mat (AGM) batteries, gel batteries, and lithium-ion batteries. Flooded lead-acid batteries are traditional and affordable but require regular maintenance. AGM batteries offer higher performance and are more resistant to vibrations but are more expensive. Gel batteries provide long lifespans but are sensitive to charging conditions. Lithium-ion batteries are lightweight, have high energy density, and offer long lifespans but come with a higher price tag.

Finally, proper maintenance is crucial for extending the life of your starting battery. Regularly check the battery terminal connections for corrosion and ensure they are snug and secure. Protect the battery from extreme temperatures and vibrations to prevent damage.

Deep-cycle batteries: what to look for

Deep-cycle batteries are designed to be repeatedly discharged and recharged, providing sustained power over a long period. They are commonly used in applications such as golf carts, RVs, and solar power systems. When buying a deep-cycle battery, there are several things to consider:

• Ensure it is a "True or Real" deep-cycle battery.
• Check the Ampere-Hour or Reserve Capacity rating meets your requirements. Most deep-cycle batteries are rated over discharge rates of 100, 20, 10, 8, or 5 hours and/or reserve capacity minutes.
• It is better to have more ampere hours (or RC) as this will deliver longer discharge times.
• Understand the battery's electrochemical design. A battery of a certain dimension designed for UPS applications may deliver more initial runtime but will not provide the same life or number of cycles as a Deep Cycle battery of the same dimension.
• Consider the available space and weight restrictions.
• Understand what you intend to use it for. For example, a flooded deep-cycle battery is best for a vehicle that remains level or a stationary application. In contrast, a VRLA battery is better for boats and RVs, as they can operate in any orientation and are less likely to be damaged by frequent tipping or side installation.
• If regular maintenance is challenging, a sealed VRLA battery may be a better option as it requires less frequent watering.
• Check the battery's fluid level and voltage after charging.
• Ensure the battery is securely mounted to minimize vibration and movement, which can damage internal components.
• Regularly inspect the battery for signs of damage, bulging, or leaks, and replace if necessary.
• Never fully discharge a deep-cycle lead-acid battery. Repeated deep discharges will reduce the battery's total cycle life.
• Always ensure the charging settings match the battery.
• Never add or replace a single battery in a battery bank. When connecting batteries, ensure they are the same age, capacity, make/type, and voltage.

Dual-purpose batteries: what to look for

Dual-purpose batteries are a combination of both starting and deep-cycle batteries. They can provide the high cranking current to start the engine and support deep discharge cycles for onboard electronics. While dual-purpose batteries are convenient, they may not perform as well as dedicated starting or deep-cycle batteries in extreme situations.

• Battery Type and Compatibility: Ensure the battery is specifically designed for marine use and can handle both starting and deep-cycle functions. Some batteries may be better suited for one purpose or the other, so check the specifications to ensure it meets your needs.
• Capacity and Size: Consider the amp-hour (Ah) rating, which indicates how much energy the battery can store and deliver over time. Match the battery size to your boat's power requirements, especially if you have a larger boat with more electronics.
• Budget: Dual-purpose batteries can vary in price depending on the brand, quality, and technology used. Lithium-ion batteries, for example, tend to be more expensive but offer higher energy density and a longer lifespan.
• Maintenance: Look for batteries that require minimal maintenance. AGM (Absorbed Glass Mat) batteries, for instance, are maintenance-free and more resistant to vibrations.
• Durability and Longevity: Opt for batteries that are designed to withstand the marine environment, including exposure to saltwater, high temperatures, and vibrations. Check for features like full sealing to prevent leaks and vibration resistance.
• Safety: Choose a battery with safety features such as a venting system to prevent gas build-up and reduce the risk of explosion.
• Reviews and Reputation: Research the reputation of the battery manufacturer and read reviews from other boaters to get a sense of the real-world performance and reliability of the batteries.
• Warranty and Support: Look for batteries that come with a warranty and have a good after-sales support system in place, so you can get assistance if any issues arise.

By considering these factors, you can make an informed decision when choosing dual-purpose batteries for your boat, ensuring you have a reliable and safe power source for all your boating needs.

Marine battery maintenance

Marine batteries are essential for boating, providing the power to start the engine and run electronics. They are also designed to withstand the harsh marine environment, including saltwater exposure, high temperatures, and vibrations.

Regular Visual Inspections and Cleaning

Perform regular visual inspections of your battery to check for any signs of corrosion, loose connections, or physical damage. Clean the terminals and cable connections with a mixture of baking soda and water to ensure a solid electrical connection. Corrosion around the terminals can prevent your battery from functioning correctly. It is recommended to do this monthly, especially during heavy usage periods.

Charging Best Practices

Proper charging is crucial for extending the life of your marine battery. Avoid deep discharges as they can harm the battery. Only use a charger designed for marine batteries, and ensure you follow the manufacturer's charging cycle recommendations. Overcharging or undercharging can reduce the battery's lifespan, so consider investing in a charger with an automatic shut-off feature to prevent overcharging.

If your boat is in storage, ensure the batteries are fully charged before storing them. A partially charged battery is more likely to freeze. Store them in a cool location to prevent overheating or freezing, and keep them on a regulated trickle charger to maintain the charge.

Battery Security and Safety

Ensure the battery is securely mounted to minimize vibration and movement, which can damage internal components. Boats move jerkily through the water, so make sure the battery is seated correctly and does not slide or bounce around. When working with your battery, always wear safety glasses and gloves, and be cautious when handling metal objects.

Battery Size and Type

When choosing a marine battery, consider the power requirements. If you have a larger boat with high-power needs, you may need a higher-capacity starting battery. Smaller boats with fewer electronics may only need a lower-capacity battery. Additionally, if you use many onboard electronics, consider a deep-cycle or dual-purpose battery with a higher amp-hour capacity.

Parasitic Drains

Before storing your boat for an extended period, disconnect the battery from any devices or systems that may cause parasitic drains. Even when not in use, some electrical components draw small amounts of power, which can lead to a discharged battery over time.

Battery Monitoring

Consider investing in a battery monitor to keep track of the battery's health and performance. A good battery monitor will provide valuable information such as amperes, remaining ampere-hours, and capacity percentage. This will help you maximize your fun on the water by ensuring your battery is always in good condition.

Frequently asked questions