Boat Battery Basics: Choosing The Right Power Source

Marine batteries are essential for boating enthusiasts to ensure their vessels have enough power to operate electrical loads such as lights, motors, and pumps. There are three main types of boat batteries: starting batteries, deep cycle batteries, and dual-purpose batteries. Starting batteries, also known as cranking batteries, provide a burst of power to start the engine, similar to a car battery. Deep cycle batteries, on the other hand, release power slowly and are designed to be drained and recharged multiple times, making them crucial for navigation and powering accessories. Dual-purpose batteries combine the functions of both starting and deep cycle batteries, making them ideal for smaller boats with limited space. When choosing a marine battery, boaters must consider factors such as performance, durability, maintenance, and cost. Additionally, battery chemistries include flooded lead acid, gel, AGM (Absorbed Glass Mat), and Lithium-Ion Phosphate, each with its own advantages and disadvantages.

Deep-cycle marine batteries

Gel batteries do not require much maintenance and rarely leak. However, they are expensive and hard to maintain if issues do occur, as it is difficult to reach their internal components. They also require more recharging, as they can only discharge to 50% depth.

AGM batteries are popular because they do not require frequent recharging and can be stored for a long time without losing their charge. However, they are expensive and slow to charge, and failure to disconnect the battery charger once the cycle is complete can cause irreversible damage.

Lithium batteries are the most advanced option. They last longer, weigh less, are hassle-free, and are non-toxic. They are also more environmentally friendly than lead-acid batteries, as they do not leak or require ventilation. They require zero maintenance and are not prone to sulfation or damage if left partially charged. They are also faster to charge than lead-acid batteries.

Dual-purpose marine batteries

Marine batteries are available in three types: starting batteries, deep cycle batteries, and dual-purpose batteries. Dual-purpose marine batteries are designed to provide enough power to start the engine and turn it over, while also providing sufficient energy to keep the trolling motor running consistently. They can be used for both starting engines and powering house loads.

The RELiON HP line, which includes the RB100-HP and RB300-HP, are dual-purpose models capable of providing up to 800 amps for two seconds to start a boat's motor. The RB100-HP is a Group 31 battery, and the RB300-HP is a Group 8D battery. These batteries are ideal for bass boats and charter fishing boats.

Dual-purpose batteries are also available in lithium variants. Interstate lithium dual-purpose batteries offer engine-starting power and deep-cycle capabilities for extended use, making them ideal for various boating needs. While lithium batteries have a higher upfront cost, their long lifespan, efficiency, and reliability make them a smart and cost-effective choice for boaters.

Ionic, a brand that manufactures lithium dual-purpose marine batteries, claims that their batteries are currently the only lithium deep-cycle batteries in the marine industry with Bluetooth technology. This feature allows users to monitor their battery charge at any time using their mobile app.

Some boats don't have room for more than one battery, so they require a dual-purpose battery. However, many boaters choose to use separate starting and deep-cycle batteries as dual-purpose batteries are not as powerful as dedicated starting batteries, and they don't last as long as deep-cycle batteries.

Marine starting batteries

When selecting a marine cranking battery, it is important to ensure that the Cold Cranking Amps (CCA) value meets or exceeds your vehicle's needs. CCA refers to the number of amps a battery can deliver at 0°F for 30 seconds without the voltage dropping below 7.2 volts. Marine Cranking Amps (MCA), on the other hand, are measured at 32°F, resulting in higher numbers. Larger engines or boats with multiple electrical systems require marine starting batteries with higher CCA ratings.

Some marine cranking batteries, such as the Redodo 12V 140Ah dual-purpose model, can also function as deep cycle batteries. These batteries can provide sufficient CCA to start an engine and power electronics such as trolling motors and navigation systems. This versatility makes them ideal for boaters who need both high cranking power and steady energy for prolonged use of onboard systems.

It is worth noting that marine starting batteries should be protected from extreme temperatures to ensure optimal performance and longevity. While some batteries can operate at temperatures as low as -20°C, prolonged exposure to extreme temperatures can reduce their overall lifespan.

When choosing a marine starting battery, consider factors such as CCA, MCA, battery size, weight, and safety features like a comprehensive Battery Management System (BMS) that protects against overcharging, over-discharging, and other potential hazards.

Marine battery maintenance

Marine batteries are essential for any boat owner, as they power the engine and any on-board electricals. There are three types of boat batteries: starting, deep cycle, and dual-purpose. Starting batteries are designed for short bursts of high energy to start the engine, while deep cycle batteries provide a more sustained power output over a longer period, and dual-purpose batteries can be used for both.

To ensure the longevity and optimal performance of your marine battery, regular maintenance is key. Here are some tips for maintaining your marine battery:

Regular Inspection and Cleaning

A visual inspection of your battery is important to check for any signs of corrosion, loose connections, or physical damage. Clean the battery terminals regularly with a mixture of baking soda and water to neutralise any corrosion build-up and ensure a solid electrical connection. During the summer, tighten your battery terminals once a month to prevent losing the connection.

Check Electrolyte Levels

If you have a flooded battery, it is important to maintain its water level using only distilled water, as regular tap water can cause calcium sulfation. Check the water level regularly, especially in hot weather and after heavy usage, and add water to cover the plates if they are exposed.

Grease the Terminals

Using dielectric grease, a type of silicone lubricant, can help prevent electrical problems and corrosion, as well as insulate and seal the battery terminals.

Secure the Battery

Make sure the battery is seated properly in the battery compartment to avoid it sliding or bouncing around as the boat moves through the water.

Charging

Always use the right cables and connect them to the correct battery terminals. Negative goes to negative, and positive goes to positive. Charge your battery at the right amp and follow the manufacturer's recommendations for charging cycles. Avoid deep discharges and overcharging, as these can damage the battery. Invest in a quality marine battery charger with an automatic shut-off feature to prevent overcharging.

Battery Monitor

Consider investing in a battery monitor to keep track of amperes coming in and out, remaining ampere-hours, and capacity expressed as a percentage. This will help you maximise your fun on the water by ensuring your battery is always ready to go!

Marine battery types

Marine batteries are designed to handle the unique challenges of the marine environment. They power everything from a boat's engine to electronics and accessories. There are three main types of marine batteries, each serving a different purpose: starting (cranking) batteries, deep-cycle batteries, and dual-purpose batteries.

Starting batteries deliver quick bursts of energy to start the boat's engine and are not designed for extended, continuous use. They are also known as cranking batteries and are designed to quickly deliver a large amount of power to start an engine. Once the engine is running, the alternator takes over, and the battery is no longer needed for long-term power.

Deep-cycle batteries are built to provide consistent power over a long period and are ideal for running electronics, trolling motors, and appliances. They are also known as house batteries and are designed for steady, sustained energy output, making them perfect for electronics like fish finders, GPS systems, and onboard appliances that require a continuous power supply over long periods.

Dual-purpose batteries combine the cranking power of a starting battery with the deep-cycle capability, providing a versatile solution for boats with limited space. However, they are less efficient than specialised batteries.

Now, let's take a closer look at the different types of marine battery technologies available:

• Lead-acid batteries are inexpensive in the short term and can be recharged multiple times. However, they require constant maintenance and are prone to breakage and leakage.
• Gel batteries are popular in marine applications due to their exceptional cycle life, resistance to vibration and shock, and ability to function in a wide range of temperatures. They also have a higher depth of discharge and recharge faster than AGM and flooded batteries.
• AGM (Absorbed Glass Mat) batteries are sealed and spill-proof, making them maintenance-free. They can handle greater charge currents and have a faster recharge rate.
• Lithium batteries, specifically LiFePO4 (Lithium Iron Phosphate) batteries, are making significant inroads into the marine market due to their stability, lightweight design, high efficiency, and long lifespan. They are more expensive but often provide better long-term value.

Frequently asked questions