About Marine Batteries

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What is a Marine Battery?

Marine batteries tend to come in two battery types, either to start a marine engine or for powering the domestic electrical systems. The domestic batteries supply power over a period of time and they perform best under slow drain situations, as a power source for appliances and equipment in many boats, watercraft and vessels. Where marine starting batteries are concerned, these are primarily designed for starting marine engines, producing a high burst of power in order to start the engine. Marine domestic batteries are used to provide a power source to the electrical equipment and appliances on board, these are charged either when the engines are running through the onboard charging system, or when the vessel is moored and hooked up to the marina main power supply.

Within the marine and leisure battery ranges you will come across ‘Dual Purpose’ batteries, these batteries have the ability to supply power over a period of time for your electrical appliances (as mentioned below), as well as having the ability to provide cranking power which can start marine engines.

Marine domestic batteries, supply a steady source of power over a prolonged period of time for onboard equipment such as: computers, sensors, bilge pumps, heating, aircon, lights, fridge, kettle, television, to name a few. Marine batteries offer the ability to make sure you have the power needed for when you’re out at sea or inland waterways when you’re away from a mains power source for charging. Making your boating experience and surroundings a more comfortable environment.

Most traditional marine batteries are lead-acid batteries, we will explain the different technologies of lead-acid batteries below. A more modern technology, ‘Lithium’ LiFePO4 batteries are becoming more and more popular with anyone who requires a power source for starting marine engines or powering equipment and appliances onboard, far more efficiently than before.

Lithium marine batteries are becoming so popular because they have almost none of the disadvantages of traditional lead-acid batteries, which we will cover in the Lithium section.

Marine Battery Technologies

Most traditional marine batteries are lead-acid batteries, we will explain the different technologies of lead-acid batteries here and help you decide which technology best suits your needs.

Wet Flooded Batteries

Lead-acid batteries which are cheaper than AGM, Gel or Lithium batteries, providing a reliable low maintenance power storage solution making them a popular choice for powering your onboard equipment. There are two main types of wet marine battery, maintenance free, which is sealed so you can’t access the inside to check electrolyte (acid) levels. The other type is open, which means you can access the inside of the battery where you’ll check the electrolyte levels during your battery maintenance schedule.

As with all wet batteries, sealed or not, they need to be handle with care due to the acid content and kept in an upright position.

Rule of thumb: The more plates which a cell contains, and therefore form a larger surface, the larger the cold start power (CCA) which the battery can deliver for engine starting. However, if the space in the cell is used for fewer, but thicker plates, the cycle stability is increased. This means that the battery is designed for a higher charge throughput (continual charging and discharging process) as would be used in marine domestic batteries.

The cells are contained in a casing which is made from acid-resistant plastic (polypropylene). Early batteries had screw plugs which enabled them to be topped up with distilled water. Modern batteries are completely maintenance-free. Water does not need to be, and must not be topped up. Although AGM batteries still have “one-way plugs”, these must not be opened under any circumstances.

AGM Batteries

AGM, or Absorbent Glass Mat batteries feature a fibreglass matting which surrounds the lead plates with the electrolyte absorbed within it. AGM batteries are spill proof (and so can be theoretically mounted in any position) and have far better vibration resistance than a standard lead-acid battery.

The major benefits with AGM batteries are their ability to withstand a greater number of charging cycles and are better able to deep cycle, making them more reliable and capable of a much longer lifespan (for various technical reasons) than their wet counterparts.

Lithium Batteries

As mentioned previously, Lithium batteries are becoming far more popular and our extensive Relion range of Lithium batteries can cover all of your Lithium requirements. One of the reasons why Lithium batteries are so popular is that they have virtually none of the disadvantages of your traditional lead-acid batteries.

Here are some of the reasons why people are making the switch to Lithium batteries:

Relion Lithium Iron Phosphate batteries can be charged in as fast as 1 hour. We recommend using a rate that charges the batteries in 2-5 hours. Please refer to the data sheet for your particular model, to find the recommended charge rates. All of our data sheets are available on our website within the product section.

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Relion LiFePO4 Lithium Iron Phosphate batteries can be discharged up to 100% without risk of damage. Make sure you charge your battery immediately after discharge. We recommend discharging to be limited to 80-90% depth of discharge (DOD) to avoid the BMS disconnecting the battery.

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Relion Lithium batteries are approximately 50% lighter and provide up to 50% more energy than traditional flooded, AGM, or Gel lead acid batteries, and they provide more power.

Battery life is measured in life cycles and Relion’s LiFePO4 is typically rated to deliver 3500 cycles at 100% depth of discharge (DOD). If the depth of discharge is kept to 80% then the life cycles can increase to 6,000 cycles.  Actual life expectancy is dependent on several variables based on your specific application. If used for the same application, a LiFePO4 battery can last up to 10X longer than a lead-acid battery.

Relion Lithium batteries are highly efficient, offer super-low resistance (and 99% efficiency), allowing much faster charging, with minimal losses.

Lead-Acid batteries lose power more quickly during discharge, having a self-discharge rate of 5 times or more than that of a Lithium battery.

When Lead-acid batteries are stored, we recommend you check the level of charge approximately once a month and charge as required.

When Lithium batteries are stored, you can happily leave them from 3 -12 months, in a dry environment between -5 to 35 Degrees C, ideally at 50% state of charge.

LiFePO4 batteries are non-toxic, non-contaminating and contain no rare earth metals, making them an environmentally conscious choice.

Relion's Phosphate-based batteries offer superior chemical and mechanical structure that does not overheat to unsafe levels. Thus, providing an increase in safety over Lithium-ion batteries made with other cathode materials. This is because the charged and uncharged states of LiFePO4 are physically similar and highly robust, which lets the ions remain stable during the oxygen flux that happens alongside charge cycles or possible malfunctions. Overall, the iron phosphate-oxide bond is stronger than the cobalt-oxide bond, so when the battery is overcharged or subject to physical damage then the phosphate-oxide bond remains structurally stable; whereas in other Lithium chemistries the bonds begin breaking down and releasing excessive heat.

Lithium phosphate cells are incombustible, which is an important feature in the event of mishandling during charging or discharging. They can also withstand harsh conditions, be it freezing cold, scorching heat or rough terrain. When subjected to hazardous events, such as collision or short-circuiting, they won’t explode or catch fire, significantly reducing any chance of harm. If you’re selecting a Lithium battery and anticipate use in hazardous or unstable environments, LiFePO4 is likely your best choice.

Unlike Lead-acid batteries which require more maintenance and have fewer operation opportunities, Relion Lithium batteries are maintenance free.

Relion Lithium batteries can be mounted in any position because there is no fluid inside LiFePO4 batteries. This gives you the flexibility to install the battery where it is best suited for your application.


Lithium Benefits For Marine

Sailors, cruisers, racers and anglers want to spend as much time on the water as possible. Long lasting Relion Lithium Iron Phosphate (LiFePO4) batteries fit all types of watercraft and deliver the dependable power for everything you need, from onboard appliances, navigation equipment and sound systems to supporting off-grid living and adrenaline packed racing.

Relion Lithium batteries are built to last and designed to perform, making the perfect energy source to power your aquatic adventures. Lightweight, durable and maintenance free, our batteries charge quickly, store safely, and withstand the harshest temperatures and conditions.

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Why Choose Lithium Batteries For Your Sailboat?

Long days of adventure call for long hours of power, and sailboats have numerous components that require serious energy. Having reliable deep cycle power that can meet these extensive demands is crucial. Relion Lithium sailboat batteries offer a solution to these needs as they provide tremendous capabilities for those moments when you’re away from it all.

Upgrading To Lithium, Is It Worth It?

Sailing Nandji made the change from AGM lead-acid batteries to Relion Lithium batteries. In the below video they explain why they made the change and provide you with information comparing the two types of batteries.

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Off Grid Living, Why We Chose Relion Lithium

The Wynns have been living off lithium battery power for the past couple years and it has completely changed their off-grid lifestyle. Watch their video explaining why they chose Relion Lithium and why they feel it’s a better investment than going for lead acid batteries.

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Pro Series Angler Explains Why He Uses Lithium Batteries

As an angler, your time on the water is your most valued asset. A bass boat needs reliable marine batteries as they are necessary for both starting and running your fishing machine. Shorter charge times and more usable capacity without any late-day voltage sag means you can spend more time chasing that fish of a lifetime.

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