Most people have never heard of an 8D battery. Its big and found mostly in boats, but is increasingly used in off grid power systems and RVs. There are a lot of battery sizes and it can be confusing to figure out what battery you need for your boat, RV, or off-grid power system. Many different brands, battery sizes, types, and features to choose from. One of the largest sizes of RV & marine batteries is the 8D battery, which is a big battery not to be confused with the Duracell D type cell battery that you would put in a flash light. An 8D battery is much bigger, about the size of a carry on suitcase. We’re here to help you figure out what an 8D battery is, what its used for, and what you should look for when choosing an 8D battery.
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An 8D battery is a size of deep cycle battery commonly found in boats, RV, and off-grid power systems. The battery industry developed group sizes to help people figure out what size battery they need. The groups are based on the physical size, as measured by length x width x height. Historically lead acid batteries needed to be larger to get more capacity. So the group size was linked to roughly how much energy the battery can store and provide. Group 8D batteries are the largest standard group size of 12-volt batteries available. Group 8D batteries have rough dimensions of about 21 inches x11 inches x10 inches (LxWxH).
8D batteries usually weigh between 120 to 180 pounds and have a capacity of 230 to 300 amp hours. They can provide around 1,500 cold cranking amps (also called CCA). And they are also very big, powerful, and heavy. That’s why Dakota Lithium 8D batteries have become so popular. They are light enough one person can carry them while giving twice the usable power and an equal amount of cold cranking amps.
The lithium battery that is a drop in replacement for a group 8D battery is the DL+ 12V 280Ah battery. At 70 lbs it is half the weight of a traditional group 8D battery, while having 3X the usable power for deep cycle applications, and the same cold cranking amps for engine starting applications. The DL+ 12V 280Ah battery is technically smaller in L x W x H and is considered a group 31 battery. But they will fit in the same compartment your old group 8D battery was in and you wont break your back installing it.
8D size was developed for lead acid batteries to hold thicker lead plates inside them. 8D in lead acid battery weight was about the max weight a person could carry at about 120 to 180 lbs. This extra lead and acid meant the batteries has more capacity and higher cranking amps than other battery groups. Group 8D batteries often would have 1,000 to 1,500 cold cranking amps for starting diesel engines large boat engines.
Dakota Lithium group 8D batteries are half the weight of a traditional group 8D battery. For example, Dakota Lithium drop in replacement for group 4D and 8D batteries is the DL+ 12V 280Ah battery. At 70 lbs it is half the weight of a traditional group 8D battery, while having 3X the usable power for deep cycle applications, and the same cold cranking amps for engine starting applications.
8D marine batteries are often used on large boats for starting the marine engine. These larger engines are often diesel, but not always. Since a Marine 8D battery has more cold cranking amps then a standard car battery you can replace a couple or up to three car batteries with a single 8D battery. The reason why not all boat owners do this is because of their size and weight. Its tough to move a 200-pound battery around. This is why the Dakota Lithium Plus 12V 280Ah battery has become a charter captain favorite for their boats. At half the weight you can enjoy the same cranking power as a marine group 8D and not have to hurt yourself moving it around in a tight space.
Battery size groups can get confusing. One size down from an 8D battery is a 4D battery. 4D batteries have dimensions around 21″x9″x10″ (LxWxH) and weigh between 100-150 pounds. They are a little bit smaller and have less capacity and cranking amps for starting an engine.
The lithium replacement for a 4D battery is the DL+ 12V 280Ah battery. At 70 lbs it is half the weight of a traditional group 8D battery, while having 3X the usable power for deep cycle applications, and the more cold cranking amps for engine starting applications.
The biggest differences are that the 4D battery is slightly smaller than 8D, has slightly less deep cycle capacity, weights a little bit less, and has less cold cranking amps. The best lithium replacement for a 4D or 8D battery is the DL+ 12V 280Ah battery. Half the weight, 3X the usable power, 5X the lifespan and reliability.
8D lithium batteries are a game changer for boat and RV owners. The Dakota Lithium 12V 280Ah 1,000CCA battery is a drop in replacement for group 4D and 8D batteries. The advantage of the DL+ 12V 280Ah battery over traditional batteries are:
The most common applications for 8D and 4D deep cycle batteries are boats, RVs, and off grid power systems. Here’s why:
RV manufactures often use 8D batteries as the RV’s house batteries, which powers the deep cycle systems. The problem for RV owners is 8D batteries are so heavy that they are a pain to replace. That is why Dakota Lithium 8D batteries have become so popular. Better technology, lighter weight, lower cost over time.
The DL+ 12V 280Ah battery is used in boat to both run deep cycle systems and start large engines. The combination of high capacity and high cold cranking amps means this battery can do both deep cycle and engine starting duty. All Dakota Lithium marine batteries also have a flat voltage curve, giving you steady power for twice as long as a lead acid battery. This means you have twice the usable power.
In comparison, if you discharge a lead acid marine battery more than 50% of its capacity (amp hours) it can damage the battery and shorten its life. This is why lithium batteries are quickly becoming the standard for marine and RV applications.
8D batteries are commonly used to build solar battery banks for cabins, tiny homes, or off grid houses. The high capacity is optimal for storing large amounts of energy produced by solar panels. For greatest efficiency the DL+ 12V 280Ah battery is highly recommended for off grid and solar applications. This is because a Dakota Lithium battery has a 95% efficiency rate vs 70% for lead acid. This means you get to use more of the energy created by your solar panels.
Dakota Lithium Batteries not only have more capacity, more power, and a longer lifespan, but they also charge faster. Up to 5X faster than traditional lead acid batteries. This give you more power when you need it, and less time waiting for your batteries to charge.
Dakota Lithium batteries last 10-15 years. To ensure you enjoy the full lifespan of your batteries they are guaranteed by a best in class 11 year warranty.
All Dakota Lithium batteries come with a built in battery management system, also called a BMS. The BMS monitors the battery, prevents damage, and makes sure the cells are balanced for maximum lifespan, and that the battery is protected from accidental short circuits, or other user error. It is a safety backup to make sure your battery will always perform at the specifications.
8D batteries have about double the capacity of a group 31 marine battery, plus more cold cranking amps for starting big boat engines. The DL+ 12V 280Ah battery is rad because it has the cranking amps and the capacity of a group D battery but it is in a smaller, lighter, and easier to install group 31 size case. You get the advantages of the smaller battery with the high power of the bigger battery.
Overall 8D batteries are a legacy of the lead acid battery industry where you need bigger batteries to get more power. Now, with the DL+ 12V 280Ah battery you can get three times the amount of usable power of an 8D battery in a smaller battery case the size of a group 31 battery. There is no need to install a 200 lb lead acid battery on your boat or RV anymore. Play harder, last longer, and go further with the DL+ 12V 280Ah battery.