Perhaps you’ve never even heard of an 8D battery. It can be overwhelming to pick out a deep cycle battery for your boat, RV, or off-grid system. There are lots of different brands, types, and sizes. One option you may come across is the 8D battery, not to be confused with D-cell for small electronics. Let’s look at what an 8D battery is, its best applications, and what options are available. 

battle born 8D

What is an 8D Battery? 

Batteries are categorized by “groups” based on their physical size. Typically, the larger a battery is, the more capacity and power it can deliver. Group 8D batteries are some of the largest 12-volt batteries available to consumers and usually have rough dimensions of about 21″x11″x10″ (LxWxH).

The large size of lead-acid 8D batteries allows them to have more, and thicker, lead plates inside them. The added plates giving more capacity and higher cranking amps than other battery groups. They also cause them to weigh a lot more. These batteries typically weigh between 130-180 pounds, have a capacity of 230-300 amp-hours, and can provide upwards of 1,500 cold-cranking amps (CCA).

large boat engines
Large Marine Engines usually need 8D batteries for starting

The large capacity and high cranking amps make these a versatile option for both starting and house batteries in large RVs and boats. Their large capacity means that you can often replace three smaller lead-acid batteries with a single 8D battery and reduce the overall battery footprint. The main drawback to these is their size and weight. It can be very difficult to move a 200-pound battery around in small spaces.

What is the Difference Between 4D and 8D Batteries? 

One group size down is 4D batteries. 4D batteries typically have dimensions around 21″x9″x10″ (LxWxH) and weigh between 100-150 pounds. Since they are slightly smaller, they tend to have less capacity and fewer cold-cranking amps. On average, 4D batteries have between 150-220 amp-hours and 900-1,300 cold-cranking amps.

Benefits of 8D Lithium Batteries

8D lithium batteries are relatively new to the market but offer some great benefits over their lead-acid counterparts. When switching to a lithium 8D battery, the only potential drawback is that you will not have the same cold-cranking amp capabilities. Lithium 8D batteries usually have a lower current limit closer to 500 amps. However, Battle Born’s 8D lithium battery can sustain short current surges over 500 amps for a half-second or less.

Weighs Much Less than 8D Lead-Acid

In general, lithium batteries weigh about half of what lead-acid batteries of a similar capacity weigh. 8D lithium batteries are no exception. For example, our Battle Born 8D lithium battery only weighs about 80 pounds but has the capacity of 3 lead-acid 8D batteries or 9 lead-acid 100Ah batteries.  This is a power equivalent weight savings of 460 pounds!

RV house batteries
8D batteries are commonly used for RV house batteries, moving a 200 lbs battery can be very difficult

Great for Large Marine or Large Off-Grid Applications

Discharging a lead-acid deep cycle battery below 50% of its capacity causes damage and shortens the battery’s life. On the other hand, you can discharge lithium batteries to more than 80% of their capacity without sustaining any damage. This increased efficiency offered by lithium batteries makes them an excellent option for replacing lead-acid batteries in marine and large off-grid applications. 

Charges 5 Times Faster than Lead Acid

Not only do lithium batteries offer increased efficiency over lead-acid batteries, they also charge faster! In fact, with the proper charge controller, lithium can charge up to five times faster than a similar lead-acid battery.

About Battle Born 8D Batteries

Battle Born lithium 8D batteries offer all of the added benefits above, plus a few other fantastic perks as well.

Comes With 10 Year Warranty

Battle Born batteries last 10-15 years even while being repeatedly discharged to 100% of their capacity. Better yet, Battle Born backs up their build quality with an industry-leading 10-year warranty.

Built-In Battery Management System

All Battle Born lithium batteries come with an integrated battery management system (BMS). The BMS monitors the battery for damage and defects, ensures it is operating within safe limits, and helps balance the charge across all battery cells. The BMS is critical to maintaining optimum performance and maximizing the life of the battery.

Battle born 8D BMS

Designed and Built in the USA

Battle Born designs and assembles our lithium batteries in Reno, Nevada using the highest quality materials and lithium iron phosphate battery cells. Most battery lines are UL listed and rigorously tested, and guaranteed to be safe. 

Are 8D Batteries Worth It? 

8D batteries offer more capacity and power with an overall reduction in weight and footprint compared to three smaller lead-acid batteries. Depending on your application and power requirements, these large batteries may be an excellent option, especially if you consider a lithium version.

The main drawback to large batteries like these is that they are very heavy and harder to maneuver than smaller batteries. However, upgrading to a lithium 8D battery will mean that you get even more capacity than a lead-acid 8D battery at about the same weight as a smaller lead-acid with a third of the capacity. Not only that, your lithium 8D battery will likely never have to be replaced, resulting in overall cost savings over the life of the battery and reliability for your power needs.

battleborn marine battery

For Power Storage Go Lithium

8D batteries are bigger, heavier, and can provide more power and capacity than other battery types. They’re a fantastic option to replace a series of smaller batteries in large applications with high power requirements. Beyond that, the recent introduction of lithium 8D batteries means you can reap most of the traditional lead-acid benefits without the added weight and a 10-15 year lifespan. Check out our industry-leading lithium 8D batteries to see if they’re a good fit for you.

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