Marine battery vs. Deep cycle – similar, yet different approaches

All batteries are meant to store electric energy, rather than generating it. They store the energy, and then release it when the chemical constituents of the inside of the battery change.

There are a number of battery types, other than the typical car battery, and each application will place different demands on the battery itself – so it is always important to select the best one for your needs.

However, it can be a confusing process, especially when looking at these two – the deep cycle and the marine batteries.

They have many similarities and function in similar ways, with some slight differences; and these contrasts determine what makes them a good fit for certain scenarios and not for others. It is important to learn the differences so as to make the most use of them, which is what we will focus on in this article.

What are the differences between marine battery and deep cycle battery?

Battery type	Marine battery	Deep cycle
Cold cranking amps	700 to 1000	800 to 1000
Reserve capacity	90 to 140 mins.	90 to 100 mins.
	Check here	Check here

Marine battery vs. deep cycle – how these two compare

Energy output

The major difference between the two is their energy output. Since marine batteries can function as deep cycle or starter batteries, they are considered a hybrid type of battery.

On the other hand, deep cycle batteries can be useful for both marine and RV applications, though their use is limited to powering applications for a long time.

There are certain types of marine batteries that are deep cycle types by default, since they will need to power the boat for a long period of time.

However, there are some marine batteries that are dual purpose, and others starting types; what adds even more to the confusion is that many people will interchange the two, using deep cycle batteries to refer to all marine batteries, and vice versa.

The types of each battery and functionality

When it comes to marine batteries, there are 3 main types, with each functioning for a specified purpose. They are:

• Starting batteries – these are specifically meant to rev up outboard and inboard motors of boats. Their build and specs allows them to deliver large amounts of marine cranking amps or CCAs (cold cranking amps), in order to start the engine. Since they are only meant for starting the engine, it is necessary to have an additional deep cycle battery that helps to power any appliances of 12V, as well as trolling motors, once you switch off the motor.
• Deep cycle batteries – these are meant to give your activities a steady power source, especially for electronics like electrical appliances and trolling motors. Rather than giving the appliances a sudden energy surge, they will give a steady electric flow until complete discharge is achieved. This is the major difference between them and starting batteries: starting batteries cannot deep cycle (or else they will be permanently damaged), and deep cycle batteries cannot start an engine or crank it.
• Dual purpose batteries – these will offer the best aspects of both deep cycle and starter batteries. They aim to deliver large amounts of starting power, as well as a significant reserve capacity that can handle deep cycling activities for electrical appliances. The usual case is that they will give good performance, whether you use them as a starting battery or deep cycle types, but they will not give exceptional performance at each task.

On the other hand, deep cycle batteries come in 4 varieties, which are:

• Lithium-ion – Also referred to as an LFP battery, they are the non-rechargeable version of the deep cycle battery. They operate through the use of LiFePO4 as its cathode, while the anode is comprised of graphite carbon. When you examine their structure and operation, they resemble the batteries that electronics such as laptops use, but the difference is that they do not heat up as much.
• Absorbent Glass Mat (AGM) – In these types, the glass mat is responsible for giving the battery its internal structure, while also supporting the lead plates and making the battery resistant to vibration. Since this is the case, it allows the plates to consist of purer lead compared to other battery types, therefore giving AGM batteries a greater power density. They come in 2 types: flat plate (where the electrolyte is sandwiched between plates that are arranged in a row), and spiral plate (the more expensive option).
• Gel batteries – these began to appear in the 1930s, and became popular because they were less prone to leaking. They are similar to AGM batteries, but the difference is that AGM are wet cell batteries, while gel batteries have a stiff electrolyte due to the addition of fumed silica. The electrolyte will function in the same way as a liquid electrolyte, as long as it interacts with the plates.Another thing to note is that the antimony (which you typically find in the lead plates of flooded batteries) is replaced with calcium in a gel battery.
• Flooded batteries – the most common type of deep cycle batteries. They have a similar appearance to the standard car battery (though with some differences). Their design allows them to go through regular discharge on a nearly complete level, making them a good choice for use on a camper or trailer. They are quite advantageous because they are affordable, and can last for many years as long as you maintain them properly.

Marine battery vs. deep cycle – a comparison review

Marine battery – Overview and key features

These batteries will come in a variety of sizes and types, ranging from the starter batteries that are meant to start engines, along with the deep cycle batteries that work well with trolling appliances and motors.

At the end of the day, marine batteries will vary greatly in their use and performance, which makes it important to know the features of good marinebatteries. These include:

• CCA rating – this is a measure of the starting power of the battery, and measures the number of amps the battery can deliver at a temperature of 0^OF in 30 seconds. The larger the CCA rating, the more likely the battery is to start any normal engine, especially those with a CCA of at least 700.
• Reserve capacity (RC) – this is the amount of time that the battery takes to drop below 10.5V while it discharges 25A of power, at the exact temperature of 80^O The higher the RC, the better the potential performance of the battery.
• Design and maintenance – it is always best to go for batteries that use AGM or gel technology than the traditional lead-acid approach, as they are much easier to maintain and will not be prone to leaking issues.
• Date of manufacture – the battery will lose its effectiveness over time, and will not maintain charge as well as it originally can. To get the best from the marine battery, it is a good idea to check the manufacturing date, and it should be at most 6 months old.

Just as there are several types of marine batteries, there are some top brands as well. Some of them are:

Optima 8052-161 D31M BlueTop dual purpose battery

This is another dual purpose battery that gives both great reserve capacity for deep cycling, and starting power. If you have an RV or boat that needs a great amount of power, this is a great choice for you.

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Optima Batteries 8040-218 D35 YellowTop dual purpose battery

Unlike the others on this list of marine batteries, this is a YellowTop Optima that works well as a dual purpose battery. It has a RC of 98 minutes, and 650 CCA, soit will pack a serious punch for your boat.

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Optima 8006-006 34M BlueTop marine starting battery

This is the most powerful starting battery on this list, exclusively made for marine engines and RVs. Thanks to the high durability casing and very good starting power (it has 1000 marine cranking amps and 800 CCA), it remains an excellent choice for your boat engine.

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What we like

• They are strong enough to withstand heavy use for several years
• Have higher reserve capacity compared to other battery types
• Will not tend to leak as often

What we do not like

• They can be quite pricey

What can you see with the marine battery?

• They can be different types: starting, deep cycle or dual-purpose. Most of them are dual-purpose types
• They have heavier lead plates compared to other battery types
• Their use depends on their build and specs
• Their design allows them to be useful in both starting an engine, as well as powering other electrical devices on the boat

Deep cycle battery – Overview and key features

Not all marine batteries are deep cycle types, though. There are several types of deep cycle batteries, which are:

• Lithium ion
• AGM (absorbent glass mat)
• Gel batteries
• Flooded batteries

There are numerous deep cycle batteries worth considering, thanks to their features and benefits, and we will highlight some of them below. They include:

VMAXTANKS 6V 225Ah

This has the benefits of quick recharging, as well as a steady inflow of electric energy, though their disadvantage is lasting for a year and losing their quality quickly after that.

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Battle Born LiFePO4 deep cycle battery

This is among the best AGM batteries around, with a rating of between 3000 and 5000 cycles, as well as a 3-year full replacement warranty from the manufacturer.

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Lifeline Marine AGM battery

This battery will allow you to support applications using low amperage, and it does so for long periods. The design also meets the strict specification of the U.S. military and Coast Guard; which says many things about its quality.

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Carmanah CMH-AGM-100 deep cycle battery

This model wins because of its impressive cost to power ratio, and is very easy to move around thanks to the built-in carrying handles.

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NPP NP6-200Ah golf cart battery

This is not the cheapest you can find, but it is also not as expensive as some other options. However, its winning aspect is the value for money it gives you, which makes it worth its price.

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What we like

• They charge quite quickly
• They are durable
• Have a steady power supply and high DOD (depth of discharge)

What we do not like

• Tend to be expensive
• Less specific output of energy

What can you see with the deep cycle battery?

• Able to handle deep discharge without damage
• Usually maintenance free
• Do not have issues with spillage of electrolyte

Verdict: So which is better? The marine battery or the deep cycle one?

In terms of both batteries, they are fairly similar in their functions and energy use, so your choice will depend on what you want to achieve. However, for purposes of more general use, the deep cycle battery is the better option, as it will allow you to power more applications compared to the marine battery.

Frequently asked questions

Can deep cycle batteries start engines?

Depending on the engine, yes they can. However, this does not apply to deep cycle marine batteries – so if you want to start your boat, you are better off getting a dual purpose model.

What about the maintenance of batteries?

The flooded battery will need greater maintenance and ventilation, as well as regular checks for corrosion. Generally, keep your batteries charged to prolong their lifespan.

How can I store a marine battery?

Different manufacturers will specify their requirements, but as a general rule:

• Never expose the battery to water
• Store them in an upright position
• Minimize exposure to vibration