When it comes to 12-volt battery types, the choice can seem a little daunting to those unfamiliar with battery technology. All 12-volt battery types are similar in that they provide power for your 12V electrical system. However, there are significant differences in how they’re designed, their capacity, the amount of maintenance required, and the cost to buy and install.
Join us as we take a closer look and find the right battery type for you!
What is a 12V Battery?
Twelve-volt batteries are commonly used in RV, boat, and other automobile systems. From a technical perspective, a battery uses one or more cells to allow a chemical reaction creating the flow of electrons in a circuit. Batteries do not create energy or power on their own. Batteries simply store energy for you to use when you need it.
The power you get from a battery is direct current (DC) power and is different than the alternating current (AC) power you get from the wall outlets in your home. If needed, DC power can be converted to AC power using an inverter.
You can connect multiple 12-volt batteries in series or in parallel to get either a higher voltage or more storage capacity. For example, if you connect two 12 volt batteries in series, you will have a 24-volt system. If you connect these same 12-volt batteries in parallel, you will still have a 12-volt system, but it will be able to power the same device for twice as long as a single 12-volt battery.
Your 12V battery system will power most of your basic systems like your lights and some appliances in your RV. You’ll charge this battery system while plugged into shore power and draw from it while traveling or boondocking.
12V Battery Types
When it comes to 12-volt rechargeable storage batteries, two primary types are currently used, Lead-Acid and Lithium-ion.
Lead-acid batteries have been around for a long time, while Lithium-ion is the newer technology. There are many types of Lead-acid batteries, so let’s start by taking a look at them first.
Flooded Lead-Acid Batteries
Lead-acid batteries are the most basic 12V battery type. They’re made of lead plates suspended in a sulfuric acid solution. This creates a chemical reaction that allows for energy to be stored.
Flooded Lead-Acid batteries are the most common variety of lead-acid batteries. You’ll need to have the right amount of water in these batteries to keep them functioning correctly. This means periodic maintenance is required to monitor this battery. Flooded lead-acid batteries generally last 2 to 5 years, depending on use and maintenance. The cost can vary widely, starting at around $100.
Since these are the most common kind of batteries, they’re also the most readily available and cheapest upfront to replace when the time comes. This type of battery also does not have any electronics in it and can produce a large current for a short period. This makes them ideal for starting batteries in vehicle engines.
Because these batteries need a specific amount of fluid in them to operate properly, you’ll need to be comfortable maintaining your battery system every 3-6 months. This can be difficult, depending on where your batteries are located in your RV.
Flooded lead-acid batteries also have the shortest overall lifespan of the main battery types and can be negatively affected by extremely hot or cold temperatures. You must also install them in an upright position or they will leak water and acid and fail.
Sealed Valve-Regulated Lead-Acid Batteries (VRLA)
Sealed valve-regulated lead-acid (VRLA) batteries eliminate most of the maintenance needs of their flooded counterparts. As their name implies, they’re sealed shut with the necessary ingredients to run correctly for the life of your battery.
Since they are sealed, as they discharge the chemical reaction starts to build up the pressure of hydrogen gas. Most of this gas gets recombined back to water in the battery, but during rapid charge or discharges, the gas pressure may exceed the battery’s safety specs. The regulator valve is used to relieve this excessive pressure but, unfortunately, at the same time, slowly decreases the capacity of the battery.
These are also reasonably easy to find come replacement time. Sealed lead-acid batteries last about the same length as flooded ones (2-8 years) and tend to cost a few hundred dollars.
No maintenance means a more hassle-free life for you. While they’re more expensive than flooded batteries, they’re still among the most budget-friendly battery options. Per energy delivered however, these batteries will cost more than flooded batteries.
As mentioned, the price increase may be important to cost-conscious buyers. The inability to maintain the battery, as well, may result in less than optimal performance over their life as some gas is lost. A properly maintained flooded lead-acid battery will outlast a sealed battery, but a poorly maintained flooded battery will have a shorter lifespan than a sealed battery.
Gel 12 Volt Batteries
The next step up in lead-acid 12V battery types is the gel battery. Gel batteries suspend their lead plates inside a thicker gel instead of a liquid and are considered a type of VRLA battery. Gel 12V batteries generally last 2-5 years and cost anywhere from $100 up to $800-900. The cost typically goes up as the capacity of the battery increases.
Gel batteries don’t require any regular maintenance, and you don’t have to worry about fluid leaking out as with flooded batteries. Because of this, they do not need to be installed upright. They also work well in high temperatures, unlike other types of lead-acid batteries. This makes them commonly used in special use cases or as high-temperature starting batteries for engines.
Gel batteries need more care when charging to make sure they’re not damaged. They require a particular type of charge controller and need slower charging cycles at lower voltages. All of this means an increased cost to the overall system beyond just the price of your batteries. Like other lead-acid types, deep discharges and fast recharge are not great for these batteries.
AGM 12 Volt Batteries
What is an AGM Battery? It is an Absorbent Glass Mat (AGM) technology that is a sealed lead-acid battery type.
In AGM 12V battery types, the lead plates sit between fiberglass saturated electrolyte mats. This allows increased efficiency in discharging and recharging. AGM batteries usually last 4-7 years and start in the $200 range.
AGM batteries don’t require any regular maintenance, are leak-free, and work well in most temperatures. They also don’t require the special charging equipment and care needed with Gel batteries and tend to have a longer lifespan.
These additional benefits come at a cost. AGM batteries can be significantly more expensive than lead-acid or gel batteries with similar capacities.
Challenges For All Lead-Acid Battery Types
All of the batteries we have discussed so far are variations of lead-acid battery technology and utilize the same internal chemical reaction. Because of this, they all suffer similar drawbacks in operational performance.
All lead-acid battery types require strict usage and charging requirements to get their full lifespan. Monitoring discharge and charge levels is required to get the full lifespan from these batteries as deep discharges and partial charges will damage the battery. These batteries also have long recharge times and need a special absorption charge cycle to get fully charged. This makes lead-acid batteries a poor choice for applications that involve lots of charges and discharge cycles, like renewable energy power applications.
Lithium-Ion 12 Volt Battery Types
Lithium-ion batteries are relatively new and are currently the most expensive of the 12V battery types. However, they offer many advantages for those willing to upgrade. Unlike their lead-acid counterparts, lithium-ion batteries work using lithium salt to create more efficient electricity storage. RV Lithium-Ion batteries cost around $900 each.
Lithium-ion batteries have the highest storage capacity of all RV 12V battery types and have the fastest and most efficient charging. They also last the longest before needing to be replaced, sometimes 3-5 times longer than traditional batteries. Lithium-ion batteries are lighter and don’t require the regular maintenance that other types of batteries do.
Finally, lithium-ion batteries can discharge more of their stored energy without damaging the battery or reducing your power, unlike lead-acid batteries. Because of all these charging benefits, this type of battery performs very well in repetitive and partial charging tasks like solar power systems.
Lithium-ion batteries are by far the most expensive up-front of the 12-volt battery types available. Additionally, since lithium-ion technology is newer, you will need to upgrade more than just your batteries if you want to convert to a lithium-ion battery system.
However, lithium-ion batteries last much longer and also employ electronics inside them that both protect the battery and you. These overall make the battery much safer than a lead-acid alternative.
Lastly, they will limit current to the nameplate label. This means most Lithium-ion 12 volt batteries will not work as an engine starting battery.
How to Choose the Best 12 Volt Battery Type For You
Picking the best 12-volt battery type for you is about trade-offs. Each battery type has advantages and disadvantages, and these can vary depending on your style of RV or travel.
The RVer on a tight budget may go for cheaper flooded lead-acid batteries, even if the long-term cost is more. Those who often operate in very hot or cold temperatures may want to avoid lead-acid batteries, however, in favor of a lithium-ion battery that will protect itself and perform better.
Gel batteries eliminate some of these issues, but the owner needs to be really comfortable with additional charging requirements.
RVers looking for low maintenance batteries should focus on sealed lead acid, gel, AGM, or lithium batteries and ignore flooded lead-acid batteries altogether.
Lithium-ion batteries are the obvious top choice, as they include an optimal mix of safety, low maintenance, efficiency, long lifespan, and power.
Choose the Best 12V Battery Type for Your Adventure
All of the different 12-volt battery types may seem complicated, but in the end, the results are the same. Once you understand your needs and budget, you should be able to use the pros and cons we discussed to make the best choice for you and your RV to keep yourself powered on the road for years to come.
We encourage you to check out our line of lithium-ion batteries assembled right here in the USA for your next RV, marine, or off-grid power need!
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