Welcome to RV Battery Types 101. As an RV parts supply business owner, I’ve had the privilege of assisting numerous RVers with their electrical system needs. In this article, I aim to demystify the various types of RV batteries, equipping you with the knowledge to confidently choose the best RV battery for replacement or upgrade needs.
The Two Main RV Battery Types by Usage
First, let’s delve into the two main RV battery types, a topic that’s particularly relevant to both motorhome and travel trailer owners. Both RV variations use house or coach batteries, which power the RV’s ‘house’ needs, such as lights, furnace fans, and other low-voltage loads. These batteries charge from sources like shore power, solar, or even the engine of the motorhome or tow vehicle, making them a crucial component of your RV’s electrical system.
Using an inverter, house battery power can also be converted into AC current to power (usually low power draw) 110V devices. I’ll discuss inverters in more detail in another article since they are a topic all to themselves.
In addition to house batteries, the other type of RV battery motorhomes have is starting batteries like your car. Their primary purpose is to get the engine turning over to start it, while trailers do not need starting batteries.
Starting batteries provide a short burst of high current to start engines. Deep-cycle batteries provide a steady amount of current over a long period. Complete discharges of deep-cycle batteries are not damaging, and they can sustain a large number of charging cycles.
Design and Construction
Starting Batteries:
- Plate Design: Have thinner plates to increase surface area, allowing for higher current output.
- Construction: Typically, they have more plates that are thinner and designed to allow maximum surface area contact with the electrolyte.
- Durability: Not designed to be discharged deeply; frequent deep discharges can damage the battery.
Deep Cycle RV Batteries:
- Plate Design: Have thicker plates to withstand repeated deep discharges.
- Construction: Fewer but thicker plates allow for deep cycling without significant damage.
- Durability: Can be deeply discharged and recharged many times.
Performance Characteristics
Starting Batteries:
- Current Output: High cranking amps to start an engine quickly.
- Discharge: Provides a large amount of current for a short time.
- Recharge: Quickly recharged by the vehicle’s alternator after starting the engine.
Deep Cycle Batteries:
- Current Output: Lower current output over a more extended period.
- Discharge: They can be discharged up to 80% of their capacity, though typically 50% is recommended for longer life.
- Recharge: Designed to be recharged slowly over a more extended period.
Maintenance and Lifespan
Starting Batteries:
- Maintenance: Typically minimal maintenance but needs to be kept charged.
- Lifespan: Shorter lifespan if used in deep discharge applications.
Deep Cycle Batteries:
- Maintenance: Depending on the type, this may require periodic maintenance (e.g., flooded lead-acid batteries need water).
- Lifespan: Longer lifespan in applications involving regular deep discharges.
Examples and Cost
Starting Batteries:
- Examples: Lead-acid starter batteries are found in most vehicles.
- Cost: Less expensive than deep-cycle batteries.
Deep Cycle Batteries:
- Examples: Flooded Lead-Acid, AGM, Gel, and LiFePO4 deep-cycle batteries used in RVs and solar setups.
- Cost: More expensive due to their construction and capability to handle deep discharges.
In the rest of this article, I’ll focus on only deep-cycle RV Battery types and variations. You can find lots of detailed information about starting batteries on the internet, as they exist in every size and shape of motor vehicle.
So, I will concentrate on deep-cycle RV battery types and their applications for RV uses.
Deep-Cycle RV Battery Types by Technology
Here are the general RV deep-cycle battery construction variations that are available and the advantages and disadvantages of each one:
Flooded Lead-Acid (FLA) Batteries
These are the most common and affordable RV battery type. They require regular maintenance, including checking water levels and ensuring proper ventilation to release hydrogen gas.
- Pros: They are Cost-effective and widely available.
- Cons: They require more maintenance and can spill acid. Venting is necessary as they can emit toxic gases.
Absorbed Glass Mat (AGM) Batteries
AGM batteries are a variation of sealed lead-acid batteries. They use a fiberglass mat to absorb the electrolyte. They are maintenance-free and more resistant to vibration and temperature extremes.
- Pros: Maintenance-free, spill-proof, better performance in cold weather, can be mounted in any position.
- Cons: More expensive than flooded batteries.
Gel Batteries
Like AGM batteries, gel batteries are sealed lead-acid batteries that use a gel electrolyte. They are maintenance-free and spill-proof.
- Pros: Maintenance-free, spill-proof, good performance in various temperatures.
- Cons: Sensitive to overcharging, which can shorten their lifespan.
Lithium Iron Phosphate (LiFePO4) Batteries
These are one variation of lithium-ion RV battery types known for their long lifespan, high efficiency, and lightweight. LiFePO4 batteries can be more deeply discharged than lead-acid batteries without damage. They provide more usable amp hours (AH) with equivalent ratings to a lead-acid battery. A built-in Battery Management System (BMS) provides monitoring and protection.
- Pros: Long lifespan, lightweight, high efficiency, deep discharge capability, maintenance-free.
- Cons: High initial cost, requires a compatible charger.
Many RV enthusiasts are now considering a power upgrade, swapping their lead-acid battery banks for a more efficient RV battery type like lithium-ion. This upgrade significantly boosts usable amp hours (AH) within the same battery bank space. With this increased power capacity, you can confidently run more energy-demanding appliances, like air conditioners or refrigerators, without worrying about power shortages.
Hybrid Batteries
Hybrid RV batteries are relatively new in the market. They combine the best features of AGM, lithium, and other battery technologies and offer a balance of performance and cost.
- Pros: Balance of performance and cost, suitable for various applications.
- Cons: Still emerging in the market, limited availability.
Each RV battery type has its own characteristics that suit different needs and budgets. Choosing the right type depends on power requirements, available space, maintenance preferences, budget, and weight. You should also consider how deeply you plan to discharge the batteries regularly.
What RV Battery Types are Owners most commonly using?
We polled our users to find out how common each RV battery type is. Here are the results:
| Battery Type | % of RVs Using This Type |
|---|---|
| Flooded Lead Acid | 54% |
| Absorbed Glass Mat (AGM) | 23% |
| Gel Batteries | 9% |
| Lithium Iron Phosphate (LiFEPO4) | 12% |
| Hybrid Batteries | 2% |
As you might expect, over half of the RVers we surveyed used traditional flooded lead-acid batteries. That’s not surprising, given that most RV manufacturers offer RVs the least expensive option.
Similarly, RV owners may want to avoid installing a more expensive replacement option when needed because of budget concerns. However, it was interesting that almost half of RVers chose to do so, highlighting the benefits of the advanced battery technology.
My Picks for the Best RV Batteries
For a complete list of recommendations for RV batteries, see this article.
Typical RV Battery Types by Voltage
6-Volt Batteries
The most common configuration for 6-volt RV batteries is to wire them in pairs with series/parallel wiring. (I have included an example of this below.) This provides 12 volts, which is what the coach needs. They are durable and have excellent deep-cycle capabilities.
- Pros: Deep cycle capabilities, longer lifespan, and high energy density.
- Cons: Requires wiring in pairs to achieve twelve volts.
12-Volt Batteries
This is the most common RV battery type by voltage, typically used alone or in parallel for more capacity.
- Pros: Easy to install and manage, widely available, and compatible with most RV systems.
- Cons: When used individually, they may not have as deep of a cycle as 6-volt batteries.
- Standard
RV Battery Bank Configurations
Series and Series-Parallel Wiring
This wiring configuration increases the voltage while keeping the capacity (amp-hours) the same. For example, two 6-volt batteries wired in series will create a 12-volt system. I highly recommend this configuration if you have room for four batteries in your battery bay. It will give you the most capacity for the footprint.
- How to Wire: Connect the positive terminal of one battery to the negative terminal of the next battery. The remaining positive and negative terminals are connected to the RV electrical system.
- Pros: Ideal for creating higher voltage systems (e.g., two 6-volt batteries to make 12 volts).
- Cons: They do not increase the amp-hour capacity.
Parallel Wiring
- Description: This configuration increases the capacity (amp-hours) while keeping the same voltage. For example, two 12-volt batteries wired in parallel will maintain a 12-volt system but double the capacity.
- How to Wire: Connect the positive terminals of both batteries and the negative terminals. Then, connect the combined positive and negative terminals to the RV’s electrical system.
- Pros: Increases the capacity, providing longer usage times.
- Cons: It does not increase the voltage.
Series-Parallel Wiring
- Description: Combines series and parallel wiring to increase both voltage and capacity. Four 6-volt batteries can be wired in series-parallel to create a 12-volt system with increased capacity.
- How to Wire: Connect pairs of 6-volt batteries in series to make 12 volts. Then, connect those pairs in parallel to increase capacity.
- Pros: Maximizes both voltage and capacity.
- Cons: More complex wiring setup.
Practical Example: Configuration for a 12-Volt System with Increased Capacity
- Components: Four 6-volt batteries.
- Wiring:
- Connect two batteries in series (positive to negative) to make two sets of 12 volts.
- Connect the two sets in parallel (positive to positive, negative to negative). This provides a 12-volt power supply but with double the capacity.
- Benefits: It provides a robust system with high voltage and extended capacity suitable for extended off-grid use.
Understanding these voltages and configurations allows you to customize your RV’s battery bank to meet your power needs best.
Determining How Much Power You Need
Usable Capacity for Deep Cycle Batteries
The first consideration when planning the size of your battery bank is the relative discharge capacity of the RV battery type you are considering.
- Flooded Lead-Acid (FLA) Batteries
- Usable Capacity: Typically, you can use up to 50% of the total capacity without causing significant damage. For example, if you have a 100Ah flooded lead-acid battery, the usable capacity is around 50Ah.
- Sources: The Wandering RV, Outdoorsy.
- Absorbed Glass Mat (AGM) Batteries
- Usable Capacity: AGM batteries allow up to 50% discharge without significant damage. Thus, a 100Ah AGM battery would have a usable capacity of approximately 50Ah.
- Sources: RVing Know How, The Wandering RV.
- Gel Batteries
- Usable Capacity: Similar to AGM batteries, gel batteries typically allow for up to 50% depth of discharge. Therefore, a 100Ah gel battery would have around 50Ah of usable capacity.
- Sources: Outdoorsy, The Wandering RV.
- Lithium Iron Phosphate (LiFePO4) Batteries
- Usable Capacity: These batteries can typically be discharged up to 80-90% of their total capacity without damage. So, a 100Ah lithium battery would have a usable capacity of 80-90Ah.
- Sources: RVing Know How, Field & Stream, The Wandering RV.
- Hybrid Batteries
- Usable Capacity: Hybrid batteries can vary widely, but they generally allow for a usable capacity of around 50% of their total capacity, similar to AGM and gel batteries. Therefore, a 100Ah hybrid battery would have a usable capacity of about 50Ah.
- Sources: RV Chronicle.
Summary: Example Capacities by RV Battery Type
| Battery Type | Total Capacity (Ah) | Usable Capacity (Ah) |
| Flooded Lead-Acid (FLA) | 100 | ~50 |
| Absorbed Glass Mat (AGM) | 100 | ~50 |
| Gel | 100 | ~50 |
| Lithium Iron Phosphate (LiFePO4) | 100 | ~80-90 |
| Hybrid | 100 | ~50 |
These values are typical for the different RV battery types listed. Still, actual usable capacity can vary depending on the specific make and model and the conditions under which they are used and maintained.
FREE Battery Bank Calculator
Use this tool to determine what minimum amp hour capacity each of the batteries in your battery bank should be to provide sufficient power for your coach’s needs.
FAQs
What type of batteries are used in RV?
RVs typically use deep cycle batteries for their electrical systems to power the coach or living section of the motorhome or travel trailer. These batteries are designed to provide steady power over an extended period.
Motorhomes also have starting batteries, like cars or trucks, to provide power to start the engine.
Does an RV need a deep-cycle battery?
Yes, an RV typically requires at least one deep-cycle battery if it has any lighting or appliances requiring 12-volt or 110-volt power.
What’s the difference between an RV battery and a regular battery?
An RV battery is designed specifically for recreational vehicles and provides power for various systems such as lights, appliances, and electronics. It is typically a deep-cycle battery that can withstand repeated deep discharges and recharges.
On the other hand, a regular battery refers to the standard batteries used in everyday applications like powering cars, motorcycles, or small household devices. These batteries are usually designed for starting engines and providing short bursts of high current.
In summary, an RV battery is optimized for supplying continuous power over a longer period, while a regular battery is primarily used for starting engines and delivering short bursts of energy.
Can I use AGM batteries in my RV?
Yes, you can use deep-cycle AGM batteries in your RV.
In Conclusion
I’ve covered the critical differences between voltages for RV battery types, like starting and deep-cycle batteries. I’ve also explained in detail various deep-cycle RV battery types and their pros and cons. We reviewed standard battery voltages, wiring configurations, and charging efficiencies for different RV battery types used in motorhomes and travel trailers.
I hope this article simplified the ins and outs of RV battery types for you and that you found it helpful. Leave a comment below if you have anything to suggest that I have missed and that you would find beneficial.
