News Blog from Autospark

The Differences Between a Car Battery and a Marine Battery

AUGUST 2016

Whether by land or sea, when you're getting around in a motorized structure, you're depending on the wonders of battery technology! However, the battery that sits in your car, truck, or ute is remarkably different to the one that powers your boat.

This is because the marine environment requires a different sort of battery in terms of construction, but also because marine batteries were simply designed to suit a different role than car batteries. Here are the key differences between a car and a marine battery – and why you definitely don't want to substitute one for another!

How Thick Are Your Lead Plates? – Starter vs. Deep Cycle Batteries
Lead acid batteries are found in both your car and your boat; essentially a set of lead plates that have been immersed in diluted sulfuric acid, an electrolyte. When immersed in the sulfuric acid, an electric charge is produced, which is then stored within the battery.

The size of the lead plates determines the type of lead acid battery. Car batteries, which fall into a class known as starter batteries, consist of lots of thinner plates. Marine batteries are made up of a combination of these same thinner plates, as well as thicker, heavier plates that are traditionally found in what are known as deep cycle batteries. Marine batteries are a cross between the starter type of battery found in cars, and deep cycle batteries, which are often used to charge solar powered systems.

The Job of Your Car Battery
Batteries do not make electricity – they store it. The batteries in your vehicle or boat take a charge when the machine is in operation. That 'charge' is then stored as energy that can be used later on.

For autos, the battery traditionally has a single purpose – to start the car. This is why they are referred to as starter batteries. It essentially powers the starter motor and ignition system. That's why when your battery is dead, your car won't start! As opposed to marine batteries, car batteries are made from a larger number of thin lead plates, which are needed to create the massive initial current to get your car started. Today, car batteries also can impact your electronic fuel injection system and other sensitive systems.

As such a central component of your car's operation, as a vehicle owner, it is wise to have your car battery and connections checked on a routine basis. This way, you'll never run into problems with a faulty or old car battery. As a general rule of thumb, car batteries will last for three to five years.

The Job of Your Marine Battery
Marine batteries on the other hand will not discharge such a huge amount of energy at one time, but rather they will supply that initial burst, as well as a continuous supply of energy. They are used to crank the engine and they supply the energy for the electrical features of the boat. Your boat's lighting, sound system, and pumps are all energised by your battery.

This is why for boats that are equipped with all the maritime extras, like GPS, navigation lights, fish finders, and other devices, it is advised to use a full, deep cycle battery. This is a better option than the traditional hybrid deep cycle/starter batteries that are otherwise used as marine batteries.

Marine batteries are more robust than car batteries. They are made up of thicker lead plates and tend to have a sturdier overall structure in order to cope with the vibrations and shaking that come with moving across lakes, oceans, and rivers. They are built to withstand the bumpy nature of marine travel without incurring damage, unlike car batteries, which are built to endure a smoother form of travel.

While there are key differences between a car battery and a marine battery in terms of construction and use, both are still lead acid batteries. They need to be handled with care during recharging or replacement in order to prevent shocks, burns, and other hazards. And it is important that the batteries and their connecting components are routinely checked.


For all your battery needs from installation to repair, Autospark is your source for vehicle and boat servicing. We stock a wide range of both car and marine batteries and can ensure that your car or boat is equipped with the right battery. Contact us to learn how we can help keep your vehicle or boat in excellent condition.

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