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Choosing a boat battery

Battery technology is always evolving and changing at a rapid pace.

Much of the advancements in battery technology comes from electric vehicles and consumer electronics. There’s a race between major brands to develop the smallest, lightest and most powerful battery. These batteries are able to make cars go further and our phones last longer without being too heavy and cumbersome. The technology, even compared to two or three years ago, is far more advanced. Who knows what the next few years will bring? Whatever happens, there’s sure to be some exciting new developments in battery technology.

So what does this have to do with boating and fishing? The good news is, much of this technology that has been developed for other industries and products can be shared and used in our boats. We can take advantage of lighter, more powerful and longer last batteries to power our boats and our onboard gadgets.

Over the following pages, let’s look at what batteries are suitable for various purposes onboard a boat and find out about the latest technology in marine batteries.

What batteries are best?

There are several styles of batteries suitable for boats and many boats these days carry more than one type.

Just like a car, to start an outboard engine we require a battery. These batteries are commonly called crank or starter batteries.

You can buy a specific crank or starting battery or you can choose the option of having a multipurpose model that starts your engine and also runs basic electrics such as your sounder and nav lights.

Typically, these batteries are charged via the alternator in your engine and don’t require you to top up the charge after a day on the water. It’s similar to a car battery in that regard.

Although that’s where the similarities end. A car battery is designed to withstand high heat and has the sole purpose of starting your engine. A boat battery, such as Century’s Marine Pro, is built to withstand vibration and pounding that a boat experiences and that type of battery is your only option on a boat. If you use a car battery in a boat, it wouldn’t last long!

The Fishing World Bar Crusher has one of these Marine Pro batteries as the starting battery and it also runs the sounder, nav lights and bilge pump.

Another point worth making is that lithium batteries shouldn’t be used as starter batteries and some engine manufacturers are rumoured to not honour warranties when lithium is used for this purpose. Of course, lithium is fantastic for running electric motors and other accessories on the boat. More on that later…

Deep cycle

Traditionally, boat users have also used deep cycle batteries. Deep cycles hold charge and are used for operating boat accessories such as electric motors and other electronics. You can think of these more like batteries on your phone. You use the boat’s accessories and they eat into the battery’s storage. The battery eventually runs out and requires recharging.

The lead acid variety of these batteries are typically large and heavy. The more charge they offer, the bigger and heavier they get. While they are heavier, they’re also cost effective and there are a few options.

Let’s look at a few different types of deep cycle batteries.

There are three most common types of lead acid batteries: Flooded, AGM and Gel.

The “Flooded” or “wet cell” battery is the most common. They’re available in many different sizes, types and uses.

These lead acid batteries usually aren’t sealed and you need to be careful when handling them that they don’t spill or leak. They also require maintenance in the form of topping up with water.

They are usually more cost effective than the other types.

The next type is an AGM or Absorbed Glass Matte. These are more expensive than the Flooded battery and are still a lead acid battery. The difference is these are sealed and are constructed differently inside.

The end result is a maintenance free battery that doesn’t spill. It has become a common type of battery to be used for charging electric motors.

Another type of deep cycle is the Gel battery. Gel batteries are also sealed, although, as the name suggests, use a gel instead of the absorbed glass matte. They’re also sealed and leak-free and require no maintenance.

The take away with deep cycle is there is no right or wrong battery. Choose one that fits within your budget, your boat, and your purpose.

It’s also worth looking at your options for recharging your deep cycle. Different types can require different chargers and some charge faster than others.


Lithium is another great option and is now commonly used on boats of all sizes. Lithium, such Century’s Lithium pro Battery, is still designed for deep cycle applications. They’re ideal for running electric motors and powering any electronics onboard your boat, from sounders to lights and pumps, etc.

Lithium has several advantages. It’s very light and can outlast a traditional deep cycle in its daily use and over life of the battery.

Some of the better lithium battery manufacturers also offer integration with apps that allow you to monitor battery level and condition. This also prolongs the life of the battery and is mighty useful. It really is the way of the future. The only problem with lithium is it’s more expensive and may be cost prohibitive for certain boats and budgets.

You may have heard the term Lithium-ion. Without going into too many technical detail, these are often preferred for smaller devices such as phones and cameras.

For boats, many users are opting for the latest LiFePO4 lithium technology.

The new Century Lithium Pro battery uses Lithium Iron Phosphate (LiFePO4) technology and are capable of delivering over 3000 cycles at 80% depth of discharge. Century says they offer a longer service life compared to lead-acid batteries.

Another advantage is they charge up to 10 times faster than a lead acid battery.

These lithium batteries are half the weight of comparable lead acid batteries and are around the same dimensions in size.

Given the massive weight difference they’re ideal for smaller boats and for dual battery set ups where weight becomes a problem.

Another aspect of any lithium deep cycle battery is the Battery Management System – or BMS. Century says the role of the BMS is to regulate and protect the charge and discharge of the Lithium battery cells, in order to protect against short circuits, over-charging or over discharge. The Century Lithium Pro has an advanced BMS system which also incorporates a Bluetooth monitoring system to monitor battery capacity, state of charge, plus voltage readings and state of health.

Lithium batteries can be recharged using a DC to DC charger, solar panel/blanket or a lead-acid “smart” battery charger which can be configured for lithium batteries – such as Century’s CC1212-XLi battery charger and maintainer.

Century’s Lithium Pro batteries are tested for performance and safety, including a “vibration” test, meaning they’re well suited to marine applications.

What battery you choose depends on many factors. We have only covered the very basics of battery technology and it’s changing so fast it’s difficult to keep up.

My advice is to go with a trusted battery brand that offers all types of batteries and look at the one that fits your needs and budget.

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