Explanation of Battery Sizes

June 26 2024 , 8 min reading time

Explanation of Battery Sizes

Batteries come in all shapes and sizes, but they can’t all provide the same amount of power from item to item. The power needs of a controller don’t compare to the energy capacity of an RV and everything inside it.

Choosing the right battery size for your RV or other off-grid vehicle is important as the wrong size can damage your system or leave you without power during important times.

Understanding Batteries

Essentially, the larger the battery, the more energy it’s able to store. The capacity to store this energy is measured in amp-hours (Ah), or watt hours (Wh). The size can also influence the performance of the battery, including the lifespan and voltage of the battery.

For vehicles, such as cars and RVs, battery sizes aren’t uniform. Typically, a manufacturer will recommend the size of a battery depending on the needs of the vehicle. With that said, most RVs, boats, trucks, and other large vehicles use 8D-sized batteries, which are large, high-capacity batteries.

Key Terms

When discussing batteries, it’s important to understand the basic terminology commonly associated with them. Having this base understanding can help you make informed, calculated decisions regarding purchases and other information.

Amp: A unit of measure for an electrical current

Amp-hours: Measures how much energy a battery can provide in one hour (100 Ah = 100 amps every hour)

Capacity: refers to an item’s ability to absorb and store energy.

Cycle: A single occurrence of when a charged battery discharges and then recharges

Discharge: When a battery converts its stored energy into electric energy and powers something (RV, remote, etc.)

Deep Discharge: Discharge of at least 80% of the capacity of the battery

Voltage (volts): The unit of measure of how much pressure “pushes” electricity through a wire

Wattage (watts): Measures the total power

Watt-hours: Measures the amount of power of an hour

Batter Sizes Explained

The batteries you use for your remote control look vastly different than the ones you use in your RV or car. However, every battery you need can easily be replaced with another with the same exact size. This is due to the Battery Council International’s battery standards. These standards ensure that any replacement battery used in your RV, van, or other vehicle will keep it running like new.

There are four categories that identify a battery to a group size:

1. Size: the physical size/dimensions of the battery
2. Performance: Measured through amps/amp-hours
3. Terminal Positions: How a battery properly aligns with the vehicle
4. Chemistry: The type of battery used (Check Types of Batteries section for more information)

For most vehicles, no single group sizing that fits RVs, vans, cars, and a plethora of other vehicles. That said, one of the most common group sizes for RVs would be BCI Group 24 size, which you can find on the Sunrich Energy website.

You can view BCI’s full list of group sizes on their site.

Basic Battery Metrics

When choosing a new battery, there are several statistics that need to be considered before making a decision. First, understand that all batteries, no matter what they look like or how they work, have two things in common:

1. Voltage
2. Capacity

How much voltage and capacity a battery can hold changes depending on the battery. To figure out how much a battery can hold in kilowatt-hours (kWh), multiply the voltage (V) by the capacity (Ah). Using Sunrich Energy’s 12V 100 Ah battery as an example would come out to 1200Wh = 100 Ah * 12V, which comes out to 1.2 kWh

Common Types of Batteries

There are four different types of solar batteries for RVs: lead acid, nickel, flow, and lithium-ion. Each is great for solar systems in RVs; however,  there are pros and cons associated with each.

Lead Acid Battery

Lead acid batteries are a reliable and budget-friendly option with two separate versions: flooded lead acid (FLA) and sealed lead acid (SLA). They are a tried and true solar battery and have been around since the 1800s.

Pros

Lead acid batteries are affordable, reliable, and perfect for off-grid systems and emergency backup batteries. They’re easy to recycle and dispose of, making them a greener alternative to some of the other batteries listed.

Cons

Lead acid batteries require regular maintenance and upkeep when installed. Likewise, there are limitations to where they can be installed, and have very short lifespans compared to some of the other available batteries.

Flow

Flow batteries are relatively new in battery technology that use water to perform chemical reactions inside the battery itself. These batteries are beginning to rise in use and popularity.

Pros

Flow batteries have a 100% complete depth of discharge and contain a long 30-year average lifespan. Likewise, due to its composition and use of water, there is minimal fire risk when using this type of battery.

Cons

Because of their newness, these batteries are much more expensive than conventional battery types. Likewise, they are large and require a lot of space yet have a low charge and discharge rate.

Lithium Ion Batteries

Lithium-ion batteries (LiFePo4) are also relatively new in the battery market but are increasingly popular to use. They are reliable, affordable, and are almost always the preferred choice for RVs and solar systems.

Pros

Lithium-ion batteries are a lightweight, compact, and high-performance battery option that is incredibly popular in the solar and RV market. On top of that, they are long-lasting and offer a deep-cycle charging/discharge rate with many added technologies, such as temperature protection.

Cons

Although incredibly popular and reliable, lithium-ion batteries have a more expensive upfront cost than some of the other options. If installed incorrectly, the chance of a thermal runway greatly increases, so making sure they are properly installed is a priority.

Factors to Consider When Choosing Battery Size

When choosing your battery size, aside from the type of battery you’re looking to get, there are other factors to consider before finalizing your decision.

Power Requirements: Consider what you’re getting your battery for. What you need for an off-grid living situation or an RV is different from the needs of an emergency or backup battery power.

Cycle: A battery is only rated for so many cycles within its lifespan. Consider how many cycles (charging/discharging) you accurately estimate you need. An emergency battery won’t need the same deep cycle longevity that a primary power source can output.

Cost: Factoring in the cost of your battery is important, especially considering the budget you may have.

Space: Batteries take up space, and you may have a limited amount of it. Make sure you measure the space you have to store your battery. If you can’t properly store the battery, you may need to reconsider what you can choose; improperly stored batteries can break and may become hazardous.

Maintenance and Longevity

Batteries require proper maintenance and care to maximize their lifespan and to work properly. Knowing how to care for your solar or RV battery is essential for worry-free use. Although all batteries are different, there are three main safety tips to consider.

First: Always read the manufacturer’s instructions before proper use. Most batteries come with warranties, so following proper manufacturer guidelines to keep your warranty is important.

Second: Make sure to properly store the battery. No matter what kind you have, even a flow-type battery that uses water, keeping your battery in a cool, dry place away from places bound to get wet is important to prevent any corrosion.

Third: Proper Charging/Discharge: Properly charging and discharging batteries is the most important way to get the most out of them. Make sure you carefully read any instructions and charge the battery using a charger designed for that type (lithium, flow, etc.). Make sure not to overcharge the battery and to only charge it up to the recommended voltage. Use a reliable battery monitor to make sure.

How to Choose the Right Size for Your Battery

After taking into consideration all the different factors that go into a battery, it’s understandable that you can’t just pick the biggest or cheapest battery on the shelf. To recap, you must consider the following:

• Use
• Longevity
• Type
• Size
• Capacity
• Maintenance

If you don’t know which battery is right for you, contact Sunrich Energy. Sunrich Energy provides easy-to-use lithium batteries that are perfect for any occasion.  

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