Your RV battery system is a critical component of your rig’s inner workings. It powers certain parts of the RV when you aren’t hooked up to shore power, and can even be used to run every electrical appliance in your rig if you have the right setup. Without an RV battery, things like dry camping and boondocking would be much more difficult, and even something as simple as pulling in a slide can become a lot of work.
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RV Battery Setup
The location of your camper’s battery can vary depending on its type. For the majority of Travel Trailers, you’ll find the battery positioned at the front of the trailer, on the tongue. In the case of most Fifth Wheels, the battery may be situated towards the front within one of the storage bays. Battery placement ranges in Motorhomes, from storage compartments and under the steps to directly underneath the motorhome.
How to install your RV battery in 4 steps
- Start by turning off all of the appliances that draw power from the battery, including minor appliances like overhead lights.
- Find where the current battery is located and then disconnect the cables—negative first, then positive.
- Clean the cables and the replacement battery’s terminals if necessary, and then insert the battery and carefully reattach the cables.
- Install any hold-down hardware that accompanies the battery, and then give it a test run!
How Much Does an RV Battery Cost?
The cost of deep cycle RV batteries varies wildly with which kind of battery you get. For instance, a single 12-volt flooded lead acid battery might cost as little as $50. Meanwhile, a lithium RV battery setup can cost thousands. That said, a lithium battery’s extended lifespan and better performance can mean the cost-effectiveness of such a battery is actually much better in the long run. Because of this, if you can foot the expense upfront and plan to keep your RV for a long time, it may be worth it.
I have a camper on a diesel truck and use two 6-volt car batteries, for both the storage capacity as well as price. And because you can find these models at most standard auto shops across the country, you can fix it or replace it without shipping something specialty.
-Zak White, Owner of White Electric Incorporated in Carbondale, CO and avid RVer
Four Common RV Battery Types
Flooded Batteries
The vast majority of RVs leave the factory equipped with a flooded battery. These batteries tend to be the cheapest option, but they also require that you
1) ensure they stay topped up with distilled water, and
2) clean the terminals from time to time, making them a high-maintenance option.
Additionally, flooded batteries are quite heavy, something that can be a problem if you’re working with a low cargo-carrying capacity in your rig.
Gel Cell Batteries
If you’re looking for an option that requires less maintenance, you might consider gel cell batteries. Instead of water, these are filled with a thick gel that won’t spill or evaporate, meaning they never have to be refilled.
Unfortunately, these batteries are just as heavy as their flooded cell cousins and they are more expensive too, meaning they may not be the best option for everyone.
AGM Batteries
The last of the lead-acid batteries, AGM batteries are interesting in that the liquid inside the batteries is absorbed into fiberglass mats, meaning there is no free-flowing liquid to worry about. This allows users to mount the batteries however they see fit. Additionally, the liquid will never need to be replenished. These batteries are more expensive than both flooded and gel cell batteries and they are pretty heavy, so they do have their cons.
Lithium Batteries
Lithium RV batteries are an excellent alternative to traditional RV batteries. Many campers who rig their RVs for solar power generation upgrade to lithium batteries, which, though expensive, offer a variety of benefits over other types. They’re lighter in weight, smaller, and don’t require the same kind of tedious maintenance other types of batteries do. (For example, wet cell batteries require you to check and replenish electrolyte levels, whereas lithium batteries are set-it-and-forget-it.)
Lithium batteries also have a much longer lifespan than other battery types, and are typically rated for 5,000 cycles, as opposed to the 400 or so cycles most lead-acid batteries get. That said, they cost approximately three times more up front, which keeps them out of the reach of some campers.
Starter RV Batteries vs. House RV Batteries
Those who aren’t well-versed in RV systems might be perplexed to know that a standard motorhome requires two batteries. The first is a standard starter battery, as in a typical car, used to give the engine a brief but powerful jolt to help it start. The other kind of RV battery goes by many names: the deep cycle battery, the coach battery, or the RV house battery.
Compared to a starter battery, RV house batteries expel less energy (measured in amps) at once, but must last for a longer period of time, as they’re responsible for routing electricity to an RV’s cabin. They power kitchen appliances, lights, and more when the RV isn’t running. A well-made deep cycle battery will last far longer than a starter battery—up to three or four times as long, in fact—meaning you shouldn’t have to replace one very often.
Why Do You Need a Special RV Battery?
Your RV battery is responsible for storing electricity that can then be used even when you aren’t able to plug into shore power or run a generator. The battery can also be charged by any solar panels you install, allowing you to save the power of the sun until you need to use it.
Your house battery needs to be a deep cycle RV battery in order to allow it to be depleted and recharged regularly without harm.
From the factory, a typical RV comes set up in such a way that the battery will run the rig’s DC electrical system. This system includes the slides, furnace, lights, and vent fans, and provides the power needed to ignite the flames to run the water heater and refrigerator in propane mode. The system will run any and all of these things until the battery dies, at which point you will either have to plug the system in to recharge the battery or find another way to charge it back up in order to keep using the DC power.
As you might imagine, allowing your battery to die with no way to recharge could make it difficult to leave a campsite if you need to pull a slide back in before moving, so be sure to keep that in mind when dry camping.
Every RV also includes an AC electrical system. This is what the air conditioner, power outlets, electric fridge, electric water heater, and other high-draw appliances use.
Typically, this system can only be used when connected to shore power or a generator. That said, it is possible to invest in an inverter, which will take the electricity from your RV’s battery and convert it into AC power, making it possible to run these things off of the house battery.
Unfortunately, these high-draw appliances will drain a single RV battery very quickly, meaning you will need a fairly large bank of batteries in order to run the AC system normally for any length of time.
What is an RV Battery Bank?
A battery bank is what you get when you join two or more deep cycle RV batteries together. This increases voltage or amps when you need more power. Many people build large RV battery banks when they wish to do a lot of off-grid camping, as the more power they are able to store, the longer they can run appliances without charging back up.
Hoping to build out your RV battery bank? Here’s what you should know.
RV Batteries in Series
Joining RV batteries in series allows you to keep the same amperage but adds extra voltage. For example, joining two 6-volt RV batteries in series gives you a total of 12 volts, but the amps remain unchanged.
A jumper wire is used to connect RV batteries. The negative terminal of one battery is connected to the positive terminal of the other battery.
Another set of cables connects the remaining positive and negative terminal to whatever you are connecting the batteries to. Connected batteries should have the same voltage and amp rating.
RV Batteries in Parallel
A parallel RV battery bank, on the other hand, increases the current but allows the voltage to stay the same. If you join two 6-volt RV batteries in parallel, you will get 6 volts, but the amps will now be increased.
Parallel connections are done by connecting two positive terminals together and two negative terminals together. This creates a negative negative and a positive positive. The batteries can then be connected to your application and will drain equally when in use.
RV Batteries in Series and Parallel
A series parallel bank is also possible. This allows you to increase voltage and amps. It requires a minimum of four batteries. Keep track of the connections you make. You can join as many batteries as you want to each other, though you may need an RV battery box to keep your separate cells safe and secure. Two sets of batteries connected in parallel can be joined together to form a series power bank.
RV Battery Maintenance
Maintaining your RV batteries will depend, to some extent, on what type of batteries you have. As mentioned above, for instance, lithium batteries require pretty much zero upkeep.
That said, other types of batteries do have maintenance needs. How well it is maintained can drastically affect the lifespan of one of these batteries.
Because of this, the answer to the question, “How long do RV batteries last?” will be very different from one set of batteries to the next and will depend on both battery type and how well the batteries are taken care of.
For the most thorough RV battery maintenance instructions, check with the manufacturer of your specific batteries. That said, here are some basics:
- Maintain electrolyte levels in flooded-cell batteries. Over time, flooded-cell batteries lose water with each charge cycle, and this water needs to be replenished. You must use distilled water to help reduce the chance of sulfation, or the formation of sulfate crystals that can occur when the battery plates are exposed to air. Check the batteries at least once per month and ensure that they’re fully charged before performing the necessary maintenance.
- Clean battery terminals to remove any corrosion that has built up. You can use a mixture of one cup of baking soda to a gallon of water, or a commercial battery contact cleaning product, and utilize a toothbrush for scrubbing.
- Charge regularly. Allowing your batteries to get too low in charge can also increase sulfation. When your batteries fall below 80%, or 12.4 volts, sulfation can begin. Thus, always recharge your batteries in a timely manner after using them.
- Avoid fully discharging. If you have wet-cell, gel-cell, or AGM batteries, try to recharge them often in order to increase their lifespan. As an example, if you discharge your battery to 50% every day, it’ll last twice as long as if you’d discharged it to 20% each day. However, also keep in mind that overcharging and hot temperatures also have negative effects on batteries over time.
RV Battery Monitors
Determining the true state of charge of an RV battery is difficult without a good monitor. Sure, most RVs include a very primitive monitor, but these don’t provide much information and the information they do provide tends to be inaccurate. An aftermarket RV battery monitor can tell you exactly where you stand, measuring the energy that’s flowing into and out of your battery as well as its state of charge or discharge.
There are many different kinds of RV battery monitors out there, most of which can be easily installed into your RV battery system. Most modern RV battery monitors include an LCD display that reads out all the critical data about your RV battery, as well as other newfangled upgrades.
- One example is the Victron Battery Monitor, which includes a temperature sensor as well, and it’s Bluetooth compatible so you can track the state of your RV batteries by smartphone.
- That said, a battery monitor doesn’t have to be fancy or expensive to be accurate. You could also purchase the simple AiLi battery monitor for less than $45. It won’t send updates to your phone, but it does make checking your battery’s status as simple as a quick glance!
RV Battery Charging
When your RV is connected to an electric outlet, the batteries charge. An RV converter/charger that converts the power from the grid into 12-volt DC and then channels this to the adapter is fitted into every RV. That said, if you choose to upgrade to lithium batteries, you will need a lithium compatible converter/charger. Additionally, those who wish to run the AC system off of a battery bank may want to consider an inverter/charger rather than a separate charger and inverter.
In addition to charging when plugged into shore power, in most cases, RV batteries also charge when the motor of your motorhome (or tow vehicle) is running. However, if you upgrade to lithium batteries, installing an aftermarket DC-to-DC charger might be necessary in order to save your alternator. Some people choose to install these aftermarket options on truck and trailer combos as well, as they often provide a much faster charge than the usual 7-pin trailer plug.
Other options for charging RV batteries include running a generator (just make sure the RV is plugged into the generator), installing a solar charging system, and removing the batteries entirely and placing them on an external RV battery charger.
While you can certainly keep your RV plugged in all the time, doing so can drain your wet-cell batteries’ water levels more quickly, so be sure you’re checking them often if you camp this way. And remember, letting your batteries get too low in charge is bad for their overall lifespan, so try to keep them charged on a regular basis.
What is the RV battery cutoff switch?
A battery disconnect switch for RV cuts off the electrical power between your batteries and the RV. Flipping the switch helps protect against electrical fires and theft when your RV equipment isn’t being used. It’s also important to shut off the power as a safety measure when you’re doing maintenance. Finally, it protects your RV batteries from excessive drain, because even when your appliances are off, they’re still draining your batteries a little bit.
Installing your own cutoff switch is a pretty quick process. Some switches require modifying the battery cover, but some don’t—it all depends on which one you get and what your RV battery setup looks like. We especially like this switch.
Usually, to install the switch, you run the negative battery cable that comes from the RV to one side of the switch, and then a shorter one from the switch to the battery. When you turn the switch it will separate the connection between these two cables, and you won’t have to get out a wrench every time you want that done.
Winterize RV Battery
Recreational vehicles are usually stored away for months during the winter. Batteries naturally discharge over time, so your battery will go flat if you don’t look after it, and this can cause problems. This deep discharge will affect the life of your battery. On top of that, a charged battery won’t freeze, but a flat one absolutely can and this will kill a battery quickly.
To avoid this problem, consider removing your batteries from the vehicle and taking them home with you. Check the voltage every month and use an external battery charger to charge it if it falls below 80%. An overnight charge should be sufficient. Another option is to keep the batteries on a trickle charger so they are being slowly charged throughout the winter.
If it is not possible to take the batteries out of your rig, you will need to take a few precautions to keep your batteries alive. First, disconnect your house batteries. Appliances such as radios, refrigerators, smoke detectors, and propane detectors consume tiny milliamps over time which can drain your battery. Just because everything is turned off doesn’t mean it doesn’t consume some form of wattage.
Check on your batteries once a week while the rig is in storage, and charge them when needed. In some cases, you may be able to plug in at the storage facility to give the batteries a good charge. In other cases, you may need to bring a generator along.
If you forget to keep your batteries charged throughout the winter, know that you may need to replace them when the camping season rolls around again.
Keeping Batteries Charged With Solar Panels
If your RV is outdoors, any solar panels you have might be able to keep your batteries charged up. That said, this will mean leaving the batteries hooked up, so you’ll want to make sure the panel can keep up with whatever might drain your batteries. Additionally, you will need to ensure you have a good charge controller to avoid overcharging your batteries, and you’ll need to ensure the panels remain free of snow, which will render them useless.
Frequently Asked Questions About RV Batteries
To finish out this post, here are answers to some of the most commonly asked questions about RV battery systems. These answers should leave you with a very clear understanding of how your RV battery system works.
How long do RV batteries last?
The lifetime of your RV battery depends on what kind of battery you have, how well you maintain it, and how often you utilize it. Lithium-ion batteries may last for as many as 5,000 charge cycles, whereas deep-cycle batteries may only last for 400 or 500.
How many batteries does an RV or motorhome have?
Every RV comes equipped with at least one house battery. Some will include two 6-volt batteries rather than a single 12-volt battery, and a few will come out of the factory with more than one 12-volt battery, but the vast majority do not. You can expand upon the factory battery by building a battery bank if you wish to have the ability to store more electricity, but this is not usually necessary unless you plan to do a lot of boondocking.
As we mentioned above, motorhomes also come with a starter battery, sometimes referred to as the chassis battery. This is just like the battery in your car and works to start the RV engine. It helps run the vehicle accessories and is charged by the alternator.
Does driving charge the RV battery?
In most cases, yes it does. That said, some custom vans do not come with this ability. Additionally, lithium batteries may require that you upgrade the charging system by adding an aftermarket DC-to-DC charger in order to preserve the vehicle’s alternator.
Does my RV need a battery?
While it is possible to use your RV while plugged into shore power without a battery, it isn’t recommended. You see, when you plug into shore power, your converter will recognize the missing battery as a totally discharged battery. This will cause it to work overtime, attempting to charge a battery that doesn’t exist. This can cause your converter to burn out quickly, leaving you with a more expensive and complicated repair than a simple battery replacement.
Another issue with using an RV without a battery involves the trailer brakes. While electric trailer brakes will still work as long as you are plugged into your tow vehicle, if the trailer happens to break away and the breakaway cable is pulled, the brakes will not engage the way they are meant to, something that could be catastrophic.
Learn More About RV Batteries
If you want to learn more about RV batteries and how to maintain and repair your RV’s issues on your own, NRVTA’s online program is perfect for you. Click here and use code RVSHARE for 5% off all courses.
The RV Owners home study course comes in two options: Online & USB.
- The USB version is $297 and includes booklets, a tweaker screwdriver, and a USB Drive with all of the HD videos. It also includes a copy of the online version. This is perfect for RVers who may not have access to good Wi-Fi or simply prefer to have a physical copy.
- The Online version is $197 and includes all of the same videos laid out in chapters using our online portal. It’s good for RV owners who have good Wi-Fi, don’t want to wait on UPS, or like to keep everything digital.
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