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Guide to 8D Battery: Deimensions, AGM VS Lithium

David Lee
David Lee
—
15/11/2023

8D battery is a kind of large battery, typically found in boats, but it’s also becoming more popular in off-grid power systems and RVs. With so many battery sizes available, it can be tough to know which one you need for your boat, RV, or off-grid setup. There are different brands, types, and features to consider. The 8D battery is one of the largest options for RV and golf cart use. It’s much bigger than the small Duracell D battery you’d use in a flashlight—about the size of a carry-on suitcase.

We’re here to explain what an 8D battery is, what it’s used for, and what to look for when choosing one.

What is an 8D Battery? 

An 8D battery is part of a standardized group size system. This system helps you choose the right battery based on its physical dimensions—length, width, and height. Battery groups were originally linked to the energy capacity, with larger batteries holding more power. Group 8D is the largest standard size for 12-volt batteries. Its dimensions are roughly 21 inches long, 11 inches wide, and 10 inches high.

8D batteries typically weigh between 120 to 180 pounds and have a capacity ranging from 230 to 300 amp hours. They can deliver around 1,500 cold cranking amps (CCA), which makes them ideal for starting engines in harsh conditions. These batteries are hefty and powerful.

That’s why lithium alternatives, like LiTime Lithium’s 8D replacement, are gaining popularity. The LiTime 12V 460Ah 8d battery weighs just 83 pounds—half the weight of a traditional 8D battery. Despite being lighter, it offers three times the usable power.

Weight of 8D Battery - Why are They So Large & Heavy?

8D batteries are large because they are designed to store and deliver a significant amount of energy for heavy-duty applications. Here are the main reasons for their size:

  1. High Capacity: 8D batteries have a large capacity, typically ranging from 200 to 300 ampere-hours (Ah) or more. This high capacity requires a larger volume of active materials inside the battery to store and deliver the energy.
  2. Durability and Longevity: These batteries are built with thick plates and robust internal components to ensure they can handle deep discharges and high current demands over long periods. The additional materials needed for durability also contribute to the larger size.
  3. High Power Output: 8D batteries are often used in applications that require high power output, such as marine, RV, and backup power systems. The larger size accommodates more cells and thicker plates, which help deliver the high current necessary for these applications.
  4. Construction and Safety: To prevent overheating and ensure safe operation, 8D batteries require adequate space for proper insulation between cells, as well as to house protective features like reinforced casings and safety vents. This adds to their overall size.

why are group8 batteries so large

Because of these factors, 8D batteries are physically large, making them suitable for applications where space is less of a concern but where high power and reliability are essential.

Weight of 8D Battery

The 8D battery size was originally designed for lead-acid batteries to accommodate thicker lead plates. In lead-acid form, 8D batteries typically weigh between 120 and 180 lbs, which is about the heaviest weight one person can reasonably carry. The extra lead and acid gave these batteries greater capacity and higher cranking amps compared to other battery groups.

However, with the advent of lithium 8D batteries, everything has changed. These modern batteries weigh approximately 80 pounds, making them far more manageable. And that’s just one of the many benefits they offer, which we’ll delve into further.

Are All 8D Batteries 12V?

The majority of 8D batteries on the market are 12V, particularly traditional lead-acid 8D batteries.

Why is this? It’s because 12V has long been the standard voltage for many applications, such as starting car engines, powering marine motors, and running RV electrical systems. For years, manufacturers have built these systems around 12V batteries, making them the default choice for most 8D battery applications. Like LiTime 12V 460Ah and LiTime 12V 400Ah LiFePO4 Lithium 8D Batteries.

However, 12V isn’t the only option available.

With the advancement of lithium battery technology and the growing variety of applications, 8D batteries are now available in 24V, 36V, and even 48V versions. These higher voltage batteries are tailored to meet the specific needs of certain equipment:

1. 24V 8D Battery

Often used in devices that require higher voltage with lower current, such as high-power inverters and solar energy storage systems. Compared to 12V batteries, 24V 8D batteries reduce the current needed for the same power output, improving transmission efficiency and saving on cable size and weight.

2. 36V 8D Battery

Commonly used in electric vehicles or high-performance equipment. The higher voltage allows 36V 8D batteries to power high-output motors more efficiently, enhancing overall performance and optimizing energy use.

3. 48V 8D Battery

Typically found in electric boats, industrial machinery, or large energy storage systems. The 48V setup offers high efficiency and minimal power loss, making it ideal for long-lasting, high-power applications.

applications of group8 battery

Is 4D Battery The Same As 8D Battery

While both 4D and 8D are deep cycle batteries, they are not the same. The main difference is their size. A 4D battery is smaller than an 8D battery, measuring 21 inches long, 9 inches wide, and 10 inches tall. It weighs between 100 and 150 pounds, and it offers 150 to 220 amp hours with 900 to 1,300 cold cranking amps (CCA).

8D batteries, by comparison, are larger and heavier, offering 230 to 300 amp hours and approximately 1,500 CCA. If you need more power or higher cranking amps, an 8D battery is the better choice.

For a more efficient, lightweight option, consider switching from lead-acid to lithium 4D or 8D batteries. Lithium 4D batteries, for example, can provide up to three times the usable power of traditional lead-acid batteries and weigh around 70 pounds.

Attribute 4D Battery 8D Battery
Size Group 4D 8D
Typical Dimensions 21″x9″x10″ 21″x11″x10″
Weight 100-150 pounds 120-180 pounds
Capacity (Amp Hours) 150-220 amp-hours 230-300 amp-hours
Cold Cranking Amps (CCA) 900-1,300 CCA Approx. 1,500 CCA

Dual-Purpose Group 8d Battery VS Deep Cycle Group 8D Battery

A dual-purpose Group 8D battery and a deep cycle Group 8D battery serve different purposes:

Dual-Purpose Group 8D Battery

As the name suggests, these batteries are designed to serve two functions. They can provide a burst of power for starting an engine and also provide a steady supply of power for other electrical systems on board. They are commonly used in applications that require both starting and deep cycling capabilities, such as motorhomes, boats, and recreational vehicles (RVs).

Dual-purpose batteries have the advantages of high cranking power for engine starting and the ability to withstand deep discharges. However, they generally have a lower capacity and cycling capability compared to dedicated deep cycle batteries.

Deep Cycle Group 8D Battery

Deep cycle batteries are specifically designed for applications that require reliable and sustained power over extended periods. They can repeatedly discharge and recharge without significantly affecting battery life. Deep cycle batteries are commonly used in golf carts, electric vehicles, solar power systems, and other applications that require a steady flow of power.

Deep cycle batteries have a higher capacity and are built to handle deep discharges. They are optimized for long-term power delivery and can withstand frequent cycling. However, they may have lower cranking power for engine starting compared to dual-purpose batteries.

How Long Do 8D Battery Last?

The lifespan of an 8D battery can vary depending on several factors, including the type of battery and how it is used and maintained. Let's compare the lifespans of AGM (Absorbent Glass Mat) and lithium-ion 8D batteries:

AGM Batteries: On average, AGM batteries have a lifespan of 3 to 5 years. However, with proper care and maintenance, they can last up to 7 years or more. Regular charging, keeping the battery at full capacity, and avoiding deep discharges can help prolong the lifespan of an AGM battery.

Lithium Batteries: Lithium batteries tend to have a longer lifespan compared to AGM batteries. They can last anywhere between 5 to 10 years or even more, depending on usage and maintenance. Lithium-ion batteries are designed to handle high charge and discharge rates, making them more durable and long-lasting.

lifespan of lithium group8 battery


Advantages of Replacing 8D Batteries with Lithium

Switching to 8D lithium batteries is a game-changer for boat and RV owners. The LiTime 12V 460Ah lithium battery is a direct replacement for both 4D and 8D batteries, offering several key advantages over traditional lead-acid batteries:

  • Less Weight: The 12V 460Ah lithium battery weighs just 86 lbs, compared to 180 lbs for a lead-acid 8D. This makes handling and installation much easier.
  • Twice the Usable Power: Thanks to its flat voltage curve, the LiTime 12V 460Ah provides steady, reliable power for twice as long as a lead-acid battery, giving you twice the usable energy.
  • 5X Longer Lifespan: The lithium battery lasts up to 10+ years and can endure over 4,000 life cycles—five times longer than traditional lead-acid batteries.
  • 5X More Reliability: You can count on the LiTime 12V 460Ah battery for five times the dependability of lead-acid options, ensuring peace of mind for years.
  • No Maintenance: Forget about watering, corrosion, or dealing with lead and acid. With a lithium 8D battery, you get hassle-free performance with no maintenance required.

Make the switch to lithium for lighter weight, longer life, and more reliable power—without the back pain!

lead acid vs lithium group8 battery

Attribute Lead-Acid 8D Battery LiTime 12V 460Ah Lithium Battery
Weight 180 lbs 86 lbs
Usable Power Standard power with declining voltage 5888Wh - Twice the usable power with steady, flat voltage
Lifespan 2-3 years (approx.) 10+ years, 4,000+ life cycles
Reliability Standard reliability 5X more reliable
Maintenance Requires regular maintenance (watering, corrosion) No maintenance, no watering, no corrosion

FAQs about 8D Battery

1. How Many Amp Hours Does An 8d Battery Have?

The amp-hour (Ah) capacity of an 8D battery can vary depending on the specific type and brand. Here’s a general range:

  • Lead-Acid 8D Battery: Typically, a lead-acid 8D battery has a capacity ranging from 200 to 300 amp-hours (Ah) at a 20-hour rate.
  • Lithium 8D Battery: Lithium 8D batteries generally have a similar or slightly higher capacity, usually ranging from 200 to 400 amp-hours (Ah) depending on the manufacturer and design.

The capacity of the battery is one of the key factors to consider when choosing an 8D battery for your application, as it directly affects how long the battery can power a device before needing a recharge.

LiTime provides 8d lithium battery with different capacity including:

LiTime Deep Cycle 8D Lithium Battery Weight
12V 400Ah 86 lbs
12V 460Ah 86 lbs
24V 200Ah 83 lbs
24V 230Ah 86 lbs
36V 100Ah 63.1 lbs
48V 100Ah 80 lbs

 

All of these batteries are featured

  • 4000-15000 life cycles, 10+ years lifespan
  • BCI Group 8D Size
  • BMS Smart Protection: Protect the battery from over-current, over-charging, over-discharging, short circuits and overheating, ensuring its health and peak performance.
  • Quality Assurance: backed up with UL, FCC, CE, RoHS, UN38.3 certificates

lithium group8 battery

2. What are the differences between 8D and Group 31 battery?

An 8D battery dwarfs a Group 31 battery in size and power. It stores and delivers far more energy. This makes it ideal for large applications like big boats or RVs. In contrast, a Group 31 battery fits smaller setups like cars or small boats. The key differences lie in size, capacity, and use.

Here are the key differences:

1. Size:

  • The 8D battery is much bigger than the Group 31.
  • Group 31 batteries are compact and easier to handle.

2. Capacity:

  • 8D batteries hold more power, thanks to their larger size.
  • Group 31 batteries store less energy, suited for smaller needs.

3. Applications:

  • Use 8D batteries for large boats, commercial vessels, or big RVs.
  • Group 31 works better in small boats, cars, or vehicles with lighter power needs.

When it comes to heavy-duty applications, selecting the right group 8D battery is essential to ensure the smooth and reliable operation of your machinery.

Remember, choosing a quality group 8D battery will not only enhance performance but also provide longevity and peace of mind for years to come.

3. How many amps does an 8D battery have?

An 8D battery’s amp-hour capacity depends on its design and chemistry. Most 8D batteries hold between 230 and 300 amp hours. This range varies because different types—like lithium, AGM, and others—offer unique capacities.

Exact capacity also shifts between brands and models. Always check the manufacturer’s datasheet for accurate details about a specific battery.

This wide capacity range makes 8D batteries perfect for high-demand applications. They deliver steady, reliable power over long periods, making them ideal for large boats, RVs, and industrial equipment. Choose 8D batteries when you need dependable performance for extended use.

David Lee
David Lee
David Lee is a renewable energy consultant with global experience in off-grid systems and battery applications, especially in golf carts. A graduate of the University of Sydney, he shares insights on sustainability through his writing.

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