[Full Guide] Starting Battery vs. Deep-Cycle Battery

When it comes to powering marines and RVs, finding the right battery is crucial. Two popular types of batteries are starting (cranking or starter) batteries and deep-cycle batteries. But what are the differences between them, and which one is the best for your needs? Let's take a closer look at these two battery types.

Part 1 Everything about Starting Battery

1.1 Definition of starting battery

A starting battery, also known as a cranking or starter battery, is designed to supply a large burst of energy over a short period, typically a few seconds, to start an engine. Starting batteries have thick lead plates, widely spaced, with a high number of thin plates to increase the surface area. They also have a high cranking amperage (CA) and a high Cold cranking amperage (CCA) rating.

1.2 Types of Starting Batteries

There are several types of starting batteries available in the market. Here are some of the most common types:

1. Flooded Lead-Acid Batteries: These are the most common type of starting batteries. They have a liquid electrolyte that requires periodic maintenance, such as adding distilled water to keep it at the proper level.

2. Absorbed Glass Mat (AGM) Batteries: AGM batteries are maintenance-free and have a different construction from flooded-lead batteries. They use an extended glass mat as a separator, which holds the electrolyte in place, making it impossible to leak.

3. Enhanced Flooded Batteries (EFB): EFB batteries are a type of flooded lead-acid battery designed for use in vehicles with start-stop systems. They provide better performance and durability than standard flooded batteries in vehicles that require frequent engine starts.

1.3 Starting Battery Design Features

When designing a starting battery, several key features are considered to ensure its optimal performance and reliability. Here are some important design features of starting batteries:

Chemical Composition

Starting batteries typically use lead-acid chemistry, which involves lead plates submerged in an electrolyte solution of sulfuric acid. This combination allows for efficient energy storage and discharge during engine startup.

Plate Construction

The plates in a starting battery are designed to maximize surface area, allowing for greater energy storage capacity. They are typically made of grids or meshes made from a lead alloy, which provides strength and durability.

Electrolyte

The electrolyte in a starting battery is usually a diluted sulfuric acid solution. It facilitates the chemical reactions between the lead plates, enabling the flow of electrons and the conversion of chemical energy into electrical energy.

Casing

The battery casing is made from a durable, heat-resistant material such as polypropylene or hard rubber. It protects the internal components from physical damage and prevents leakage of electrolyte.

Terminal Design

The battery terminals provide the connection points for electrical cables. They are designed to be corrosion-resistant and provide a secure and reliable electrical connection.

Sealing

Starting batteries are typically sealed to prevent electrolyte leakage, which ensures safety and allows for maintenance-free operation. Sealed batteries are often referred to as "maintenance-free" or "maintenance-free AGM" (Absorbent Glass Mat) batteries.

Cold-Cranking Amps (CCA)

CCA is a measure of a battery's ability to start an engine in cold temperatures. Starting batteries are designed to deliver high CCA ratings to provide sufficient power for quick engine cranking, particularly in colder climates.

Vibration Resistance

Starting batteries need to withstand the vibrations and shocks associated with engine operation and vehicle movement. They are designed with features like reinforced plates and internal structures to ensure durability and prevent damage from vibration.

State of Charge (SOC) Indicator

Some starting batteries include a built-in SOC indicator, such as a charge level gauge or a hydrometer. These indicators help users monitor the battery's charge status, allowing for timely recharging or replacement when needed.

Size and Form Factor

Starting batteries come in various sizes and designs to fit specific applications and vehicle types. The battery's physical dimensions and form factor must match the vehicle's requirements to ensure proper installation and compatibility.

1.4 Advantages and Disadvantages of Starting Battery

A battery starter, also known as a jump starter or booster pack, is a portable device used to start a vehicle with a weak or dead battery. Below are the advantages and disadvantages of using a battery starter:

Advantages

Portability: The battery starter is a portable device that can be used anywhere to jump-start a vehicle without the need for a second vehicle or long jumper cables, making it ideal for emergencies.

Safety: Battery starters are relatively safer compared to traditional jump-start methods as it has less risk of electric shocks or explosions.

Fast Start-up: Battery starters can help start the vehicle faster since it provides direct power to the battery, unlike traditional jump-start methods, which rely on another vehicle's battery charge.

No External Power Required: A battery starter does not require an external power source making it ideal for remote locations or when you are stranded on the road.

Disadvantages

Limited Use: Battery starters have limited power and can be used only a few times before they need to be recharged. This can be an issue, especially if you tend to use it frequently.

 Expensive: Battery starters can be expensive compared to traditional jumper cables, which are generally cheaper.

 Maintenance: Battery starters require maintenance, such as periodic charging and storage in a cool, dry place to maintain their effectiveness. This can be time-consuming and can add to its cost.

 Malfunction Risk: There is always a risk that battery starters could malfunction, and in some cases, it can be dangerous, particularly if it overheats or short circuits.

 In conclusion, a battery starter can be a reliable solution for jump-starting a vehicle in an emergency. Knowing its advantages and disadvantages will allow you to make informed decisions when considering using a battery starter.

Part 2 Everything about Deep Cycle Battery

2.1 Definition of Deep Cycle Battery

A deep cycle battery is a type of rechargeable battery that is designed to provide power over a long period and withstand repeated discharging and recharging cycles. Unlike a starting battery, which is designed to provide a quick burst of power for engine cranking, a deep cycle battery is engineered to deliver sustained power for extended periods of time.

Deep cycle batteries are commonly used in backup power systems, off-grid solar systems, and electric vehicles, as well as boats and recreational vehicles that require an independent power supply. They are typically made of lead-acid chemistry, either flooded or sealed (such as AGM or gel), but can also come in other chemistries like lithium iron phosphate (LiFePO4).

The main features of deep cycle batteries are their larger capacity and thicker, more closely spaced plates, compared to starting batteries. This design enables them to withstand discharging down to a much lower state of charge and recharging multiple times without significant damage to the battery.

Deep cycle batteries are also rated in Ampere-Hours (Ah), which represents how much current the battery can deliver over a certain period. A deep cycle battery is a reliable and efficient power source that can provide sustained power for applications that need it.

2.2 Types of Deep Cycle Battery

1. Lead-Acid Batteries: These are the most commonly used deep cycle batteries and are available in two types - flooded lead-acid (FLA) and sealed lead-acid (SLA). FLA batteries require regular maintenance as the electrolyte level needs to be checked and topped up periodically. On the other hand, SLA batteries are maintenance-free.

2. Lithium-ion (Li-ion) Batteries: Li-ion batteries, such as LiFePO4 batteries are gaining popularity in the deep cycle battery market due to their higher energy density, longer life, and lighter weight compared to lead-acid batteries. They are also less prone to sulfation and can be charged faster.

3. Nickel-Cadmium (Ni-Cd) Batteries: Ni-Cd batteries are another type of deep cycle battery, but they are less commonly used due to their toxicity. However, they have a longer cycle life compared to lead-acid batteries and can operate in extreme temperatures.

4. Nickel-Metal Hydride (Ni-MH) Batteries:Ni-MH batteries have a higher energy density compared to Ni-Cd batteries and are also less toxic. However, they are less efficient in extreme temperatures.

Lead-acid and LiFePO4 batteries are the primary types of deep cycle batteries available in the market today. While lead-acid batteries have been around for longer and are less expensive, LiFePO4 batteries have become increasingly popular due to their higher energy density, longer cycle life, and improved safety features. Learn more differences on  A Complete Comparison Between LiFePO4 Battery And Lead Acid Battery. 

2.3 Deep Cycle Battery Design Features

Deep-cycle batteries are specifically designed to provide sustained power over extended periods, making them ideal for applications requiring continuous or deep discharges followed by recharging. Here are some key design features of deep-cycle batteries:

Thick Plates

Deep-cycle batteries typically have thicker plates compared to starting batteries. Thicker plates increase the surface area, allowing for greater energy storage capacity and better resistance to the chemical and physical stresses of repeated deep cycling.

Active Material Composition

The active material on the plates of deep-cycle batteries is often a sponge-like lead dioxide (positive plate) and pure lead (negative plate). This composition enables the battery to handle repeated deep discharges and recharge cycles.

Electrolyte Concentration

The electrolyte in deep-cycle batteries is usually more concentrated compared to starting batteries. A higher concentration helps support extended discharge and recharge cycles by providing a larger reservoir of active material in the electrolyte.

Reinforced Plate Structures

Deep-cycle batteries are designed with reinforced plate structures to withstand the mechanical stresses associated with deep cycling. These reinforcements can include thicker plate supports and additional separator materials to prevent damage and loss of active material.

Separator Design

The separators in deep-cycle batteries are designed to withstand the rigors of repeated cycling while preventing the plates from coming in contact and causing a short circuit. They are typically made from materials such as microporous polyethylene to provide adequate electrical insulation.

Battery Case

The case of a deep-cycle battery is built to withstand vibrations and protect the internal components. It is usually made from a durable material like polypropylene, which provides mechanical strength and resistance to corrosion.

Deep Discharge Cycling

Deep-cycle batteries are designed to handle deep discharge cycles, meaning they can be discharged to a significantly lower state of charge compared to starting batteries without experiencing significant degradation in performance or capacity.

Capacity Ratings

Deep-cycle batteries are often rated based on their capacity to deliver energy over a specific period. Common capacity ratings include Ampere-Hour (Ah) and Reserve Capacity (RC), which indicate the total amount of energy the battery can deliver before needing to be recharged.

Cycle Life

The cycle life of a deep-cycle battery refers to the number of full discharge and recharge cycles it can withstand before experiencing a significant reduction in capacity. Deep-cycle batteries are designed to have a high cycle life to ensure long-term reliability.

Voltage Stability

Deep-cycle batteries are engineered to maintain a relatively stable voltage throughout the discharge cycle, allowing for consistent power delivery. This stability is important for applications where a stable power source is required, such as renewable energy systems or electric vehicles.

2.4 Advantages and Disadvantages of Deep Cycle Battery

Advantages

Longer lifespan: A deep cycle battery typically lasts two to three times longer than a standard starting battery due to its rugged construction and ability to handle repeated discharge and recharging cycles.

More efficient and durable: Deep cycle batteries are designed to deliver power over an extended period, making them more energy-efficient and durable than starting batteries.

Greater capacity: A deep cycle battery has a larger capacity than a traditional starting battery, meaning it can retain more energy and run for longer periods before requiring a recharge.

Versatility: Deep cycle batteries can be used in a wide range of applications, from off-grid solar systems to backup power supplies in homes and businesses.

Disadvantages

Initial cost: Deep cycle batteries can be more expensive than starting batteries, especially if they are made of advanced materials such as lithium-ion.

Weight: Deep cycle batteries are often heavier than starting batteries due to their thicker plates and larger capacity.

Slow charging time: Due to their larger capacity, deep cycle batteries can take longer to charge fully than starting batteries.

Sulfation: If a deep cycle battery is allowed to discharge too much or is left in a discharged state for an extended period, sulfation can occur which can reduce its lifespan and performance. This could happen to both lead-acid and LiFePO4 battery.

Part 3 Comparison of Starting Battery Vs. Deep-Cycle Battery

1. Differences in Function:

Starting batteries are designed to provide a burst of high current to start an engine, and then be quickly recharged by the alternator. They are made to supply high electrical current for a short period of time, but not for an extended period of time. They are not designed to be deeply discharged and recharged repeatedly like deep-cycle batteries.

Deep-cycle batteries, on the other hand, are designed to provide a steady, lower current for a longer period of time. They are typically used for applications such as RV house batteries, off grid life, trolling motor batteries, and solar panel batteries. They are designed to provide a sustained flow of electrical power over an extended period of time and to be deeply discharged and recharged repeatedly.

2. Differences in construction:

In terms of construction, starting batteries typically use thinner and more numerous lead plates to increase the surface area and provide a high current output. They are designed to withstand a high number of shallow discharges and recharges.

Deep cycle batteries, on the other hand, usethicker and fewer lead plates which can handle deep cycling. Deep cycle batteries are designed to discharge to a much greater percentage of their full capacity while remaining functional, whereas starting batteries will quickly fail if deeply discharged.

3. Differences in discharge rates

The typical discharge rate range of a starting battery is 5-25 C, and CCA or MCA is one of the common indicators used to evaluate the starting ability of a battery, and its value is generally between several hundred to thousands. For example, common CCA values for automobiles are typically between 500 and 1000, while heavy trucks can have CCA values in the thousands. But it should be noted that different brands and models of batteries will have different C values and CCA values.

The discharge rate of a deep cycle battery is relatively low, typically ranging from 0.05 to 0.2 C. Although they may not provide the high current starting power of a starting battery, they are designed to provide continuous, long-term power. They can output power over a longer period of time at low to moderate currents and are typically designed to handle several hundred to several thousand deep discharge cycles, with a maximum depth of discharge rate of up to 80%. This makes the deep cycle battery ideal for applications that require continuous power, such as RVs, marine vessels, and solar power systems.

4. Differences in lifespan

Starting batteries are typically designed for shorter cycles and have a lifespan of around 3-5 years.

Deep cycle batteries, on the other hand, are designed to be discharged and recharged repeatedly and can last anywhere from 4-8 years depending on usage and maintenance. Lead-acid battery’s lifespan is generally 3-5 years. LiFePO4 battery, with advanced technology, the life cycle can up to 4000-15000 cycles ( up to 10 years lifespan).

Some factors that can affect battery lifespan include the number of discharge-charge cycles, depth of discharge, temperature, and charging habits. It's important to choose the right type of battery for your application to optimize its lifespan and ensure reliable performance.

Part 4 Battery Tips for Best Performance

For optimal battery performance, it is important to adhere to the manufacturer's instructions regardless of the battery chemistry chosen. Keep in mind that the suggestions below are applicable to flooded, gel, and AGM batteries, and that lithium batteries have unique considerations discussed in our West Advisor article on that topic.

It is recommended that you stick with one type of battery chemistry (flooded, gel, or AGM), as each requires specific charging voltages. Using different battery types may result in under or overcharging and necessitate replacing all onboard batteries simultaneously.

Do not mix old and new batteries in the same bank; this may appear to increase overall capacity, but the older batteries may drag down new ones to their degraded level.

To promote battery life and shorten charge time, regulate charge voltages based on battery temperature and acceptance. Ensure that your charging system can supply sufficient amperage to charge the entire battery bank efficiently; typically, an alternator output ranging from 25% to 40% of your battery bank's capacity is preferable.

Keep your batteries clean, cool, and dry, and make sure to examine terminal connectors frequently to avoid conductivity loss. Flooded lead-acid batteries will require distilled water additions when necessary. Maintain charge levels because leaving batteries uncharged for an extended period may harm them and diminish their capacity. If corrosion develops, use a mixture of baking soda and water to clean it up.

FAQS about Deep Cycle and Cranking Battery

1. Can You Use A Deep Cycle Battery As A Starting Battery

While a deep cycle battery can be used as a starting battery in a pinch, it is not an ideal choice. Deep cycle batteries have lower cranking amps (CCA) than starting batteries, which means they may struggle to deliver the initial burst of power necessary to start an engine, especially in colder temperatures. Additionally, using a deep cycle battery as a starting battery may decrease its lifespan since the repeated high current draws during engine starts can cause internal damage.

2.Can lithium batteries be used for engine starting?

 While lithium batteries offer superior performance for powering house loads, most are not designed for engine starting. All of Litime’s LiFePO4 batteries are deep cycle, so it’s not recommended to use as starting battery.

3. Can you run a cranking battery and deep cycle in parallel?

It’s not a good idea. Here are some reasons why:

• Different Charging and Discharging Characteristics:  Cranking batteries and deep cycle batteries have different charging and discharging characteristics. Cranking batteries are designed to deliver a brief but powerful burst of energy, whereas deep cycle batteries are designed to provide a slow, consistent delivery of energy over a longer period of time. This means that if you try to charge both types of batteries together, the charger may not be able to optimize the charging parameters for both types of batteries simultaneously.
• Mismatched Charge Levels: Because of the difference in charging and discharging characteristics, using a cranking and deep cycle battery together will likely result in mismatched charge levels. This means that the two batteries may not have equal levels of charge, which can lead to decreased battery life and potentially damage the batteries.
• Overloading: When using cranking and deep cycle batteries in parallel, there is a risk of overloading the system, especially if one battery starts to fail or malfunction. This can cause a sudden discharge of energy that can lead to damage or even injury.

4. What is a downside of using deep-cycle batteries?

One significant drawback of deep cycle batteries is the need for regular maintenance. The lead plates in these batteries tend to deteriorate when they are exposed to the atmosphere. As the battery operates, the fluid level inside it decreases, causing the plates to be exposed to air.

When the plates come into contact with air, they start to deteriorate, leading to battery corrosion and eventual failure. Once this occurs, you will need to replace the battery with a new one.

To circumvent this issue, an alternative solution is to upgrade to lithium deep cycle batteries. Lithium batteries offer several advantages, including reduced maintenance requirements, longer lifespan, and greater resistance to deterioration. While they may have a higher upfront cost, their superior performance and longevity can make them a worthwhile investment in the long run.

Suggest reading: Everything About Battery Terminal Corrosion And How LiFePO4 Batteries Can Help Prevent It

5. Can You Use a Marine Battery in a Car?

Yes, it is possible to use a marine battery in a car, but there are a few considerations to keep in mind. Marine batteries are typically designed to provide a steady amount of power over an extended period, which is suitable for powering electrical components on boats. However, car batteries are generally optimized to provide quick bursts of power to start the engine.

If you opt to use a marine battery in a car, it's essential to ensure that the marine battery has the necessary specifications and capacity to start the car's engine. Additionally, marine batteries are often built to withstand conditions such as constant movement and vibrations, which can differ from the conditions experienced by a car battery.

Before using a marine battery in a car, it's important to verify that the battery's specifications align with the requirements of the vehicle, including the necessary cold cranking amps (CCA) for starting the engine. Consulting with a professional or the manufacturer's guidelines can provide valuable insights into whether a particular marine battery is suitable for use in a car.

 

Conclusion

Overall, starting and deep-cycle batteries are designed for specific purposes and offer different advantages and disadvantages, so it's essential to choose the right one for your needs.

To optimize your battery system, it is best to use a battery bank consisting of two or more identical deep cycle batteries. This will ensure they have similar charging and discharging characteristics, and the system will not be overloaded.

Additionally, choosing a reliable and high-quality battery brand, such as LiFePO4 deep cycle batteries from Litime, can help you maximize the lifespan and performance of your battery system. Whether you are using batteries for your RV, trolling motor, or off-grid life, LiFePO4 deep cycle batteries are a great choice for their durability, high energy density, and long lifespan.

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