By Pete | My Husband’s Corner
Some RV tips and hacks deal with a specific system in the trailer … like the electrical system and how you power it.
The best camping gear is very personal because every RVer has their own style of camping and different demands on their equipment.
The best RV battery for you depends … are you a regular boondocker or do you like hanging out at RV parks and campgrounds with full hookups?
Let’s keep this potentially complex topic simple with our tips on how to choose, use and maintain your deep cycle RV battery.
The Best RV Battery Is Different For Everyone
Let’s start with some terminology before deciding which is the best RV battery to keep your electric needs supplied and your camping safety a top priority.
RV Battery Terminology
There are 4 major types of RV batteries. They fall into these categories:
- AGM RV Batteries
- RV Gel Batteries
- Lithium RV Batteries
- Flooded Lead Acid RV Batteries (12 volt and 6 volt)
AGM RV Battery
You may hear the term AGM Deep Cycle RV Battery or AGM RV battery which refers to Absorbent Glass Mat.
The benefits of this RV battery type is that they are lighter, non-spillable, charge 4-5 times faster, their lifespan is up to 2-3 times as long as the typical flooded deep cycle RV battery.
The electrolyte is suspended in a fiberglass mat and is sealed so no inspection or maintenance is required.
This AGM RV battery type is on the more expensive end of the RV battery spectrum.
RV Gel Batteries
RV gel batteries are leak proof but they have major disadvantages: they charge at a slower rate and lower voltage.
The electrolyte is suspended in a gel and is sealed so no inspection or maintenance is required.
These Deep Cycle RV Gel Batteries are on the more expensive end of the RV battery spectrum.
One of the major disadvantages of an RV gel battery is the potential of permanent damage to the cells if the battery is overcharged.
Lithium Ion RV Battery vs. Lithium RV Battery
Lithium RV Batteries are relatively common in the RV industry.
Lithium “Ion” Batteries, on the other hand, have not reached the RV industry to any significant level yet because of their size but you can easily find Lithium “Ion” Batteries for quads and motorcycles
The Lithium RV Battery price is the most expensive but has great cost/benefit, here’s why:
- RV lithium batteries are sealed resulting in no dangerous vapors and requiring no maintenance.
- The usable amps are much higher than a lead-acid style battery which means you can draw a lithium RV battery down to a lower level without damaging the battery.
- These high-performance batteries can tolerate many more cycles without losing any capacity or lifespan which is generally up to 10 years. A typical RV lithium battery is rated at 5,000 cycles compare to a typical lead-acid RV battery which is rated at only 400 cycles.
- A lithium battery for an RV weighs much less than an equally rated lead-acid RV battery.
- They perform well in a wide range of temperatures, particularly at high temps.
- The lithium RV battery has protection against short circuits and overcharge/undercharge conditions.
- Even though the lithium RV battery price is more expensive than any other style of RV battery, when you consider the fact that they provide over 10 times the number of cycles and have a much longer lifespan, lithium batteries are actually economical to operate per cycle in your RV.
Flooded Lead Acid RV Batteries (12 volt and 6 volt)
Most commonly, an RV battery is a lead-acid flooded deep cycle RV battery that has more capacity than a normal car battery.
A deep cell RV battery is designed to provide a relatively constant flow of power with more long-term energy and to be frequently charged and discharged.
In contrast, a car battery is designed to provide higher cranking amps in a short period of time for engine starting.
A lead-acid flooded deep cycle RV battery consists of a series of lead plates encased in a hard plastic shell and submersed in electrolyte (a mixture of sulfuric acid and water).
This style of battery does require a little bit of care and maintenance.
To keep this battery healthy and working well, periodically checking for proper levels of electrolyte is critical.
This type of RV battery is on the less expensive end of the RV battery spectrum and is the most commonly used in the industry.
Flooded cell type RV batteries come in either 12 volt or 6 volt types.
The 12 volt deep cycle RV battery is more common than 6 volt RV batteries.
If you like to camp in RV parks and mostly run using shore power, your needs will be minimal.
In this case, a single group 24, 12 v deep cycle battery rated around 80 Amp hours will be sufficient.
This type of battery is usually secured in an RV Battery Box and mounts near the trailer hitch.
6 volt RV batteries, which are actually golf cart batteries for RVs, have thicker internal plates which allow them to store more energy providing additional long-term power compared to a 12v RV battery.
Depending on your needs, you may want to use 6 Volt RV batteries in sets of two, four or six (they must be installed in pairs and connected with cables for a 12 volt DC system).
6 volt AGM RV batteries are also available.
RV Battery Groups
RV battery group ratings refer to the physical size of the battery case which generally corresponds to the amp hour rating of a particular battery.
The lower the group number, the lower the amp hours.
A group 24 deep cycle RV battery provides 70-85 Amp hours. Here are the category breakdowns:
- Group 24 RV battery (70-85 Amp hours)
- Group 27 RV battery (85-105 Amp hours)
- Group 31 RV battery (95-125 Amp hours)
RV Solar Battery
The term “RV solar battery” is a misnomer and not really accurate because the battery is not a solar battery, it is actually a term referring to how a regular 12v deep cycle RV battery is recharged using Solar Panels.
Any of the four RV battery types we have discussed in this post, can be considered an RV “solar battery” if it is being recharged with solar panels.
RV Marine Battery
The term RV marine battery refers to a typical deep cycle battery that is used in boats and RVs.
They are designed to tolerate deep discharge and many charging/discharging cycles.
When it comes to motorhome batteries, the same rules apply … except that higher demands require larger battery banks that usually consist of the flooded 12 or 6 volt RV battery class.
Common Questions About RV Batteries
What are RV Battery Inverters, Converters And Chargers?
- RV Battery Inverters
- Transforms DC → AC
- Makes wall plugs useful
- Permanent/wired-in installation may be factory installed or aftermarket modification
- Want to install one yourself? We have tips and a VIDEO that shows you how to install a power inverter in a camper.
- RV Battery Converters
- Transforms AC → DC
- Recharges a battery
- Permanent/wired-in installation may be factory installed or aftermarket modification
- RV Battery Chargers
- Transforms AC → DC
- Recharges a battery
- Temporary portable unit
What is an RV battery and what are travel trailer batteries used for?
Travel trailer batteries are used to run all the DC components in the trailer like water pump, lights etc.
If you have a factory installed inverter system (or an aftermarket installed modification) your travel trailer battery system will also power the AC electrical system through the RV’s wall outlets.
If you don’t have the luxury of a built-in inverter system, the next best way to get AC power is with a Small Portable Inverter that either plugs into the RV’s 15A cigarette lighter socket (if installed) or directly connects to your RV battery terminals.
These small portable inverters are restricted to lower-power demand items.
When we say lower-power demand, we mean LOWER … you won’t be running a hair dryer or space heater with this thing … you can only run equipment like a fan or laptop computer.
There is no reason to use an inverter if you don’t need one.
Because a laptop is DC powered, you can avoid using an inverter that takes DC power from your RV battery, converts it to AC, then back to DC through your normal computer plug … really, what’s the point of that?
It makes sense if you have an inverter and you don’t want to carry another piece of equipment … BUT, it is an inefficient way to power your laptop.
Instead, you can use a DC Cigarette Lighter Charger For Laptops.
You plug it into your RV’s cigarette lighter outlet connection (assuming you have one) … plug the other end into your laptop (get the right style that is compatible with your laptop) … and you will be charging your machine from your RV battery.
Pure Sine Wave Inverters vs. Modified Sine Wave Inverters
There are two types of inverter systems: pure sine wave and modified sine wave.
The type of inverter you need is determined by the equipment it will operate.
Appliances with AC motors and delicate medical equipment must be operated using pure sine wave inverters.
Examples include: some CPAP machines and oxygen concentrators.
Some equipment will operate using a modified sine wave inverter BUT it could be less efficient and may shorten the lifespan of the components.
Some examples include: microwave ovens may produce less heat, TVs and computers may have rolling lines in screens and surge protectors may overheat.
If your equipment can safely and efficiently operate with a less expensive modified sine wave inverter … Great!
But, if you will be operating sensitive equipment, you may want to invest in the more expensive pure sine wave inverter because it may cost you less in the long run.
When you use these types of inverters, your RV batteries must be fully charged because they are designed to turn off below approximately 11 volts depending on the brand and condition of the unit.
If your RV battery gets too low, most inverters will start beeping to indicate low input volts and the inverter will soon stop providing AC power.
This 750W Modified Sine Wave Inverter will power equipment such as a fan, small TV, drill, mini fridge etc.
The cigarette lighter plug should not be used with loads higher than 150W because the maximum allowed current through the cigarette lighter outlet is only 15A.
So, if you want to run a load higher than 150W you should use the battery alligator clips to connect directly to your 12V RV battery terminals.
This inverter also comes in a 500W version for charging equipment that requires less power.
If you jump to the next higher level of this inverter (1000W or 2000W) you need to connect the inverter directly to the RV battery … the cigarette lighter outlet connection is not even an option with this larger capacity inverter… but it gives you the ability to run much higher demand equipment.
The manufacturer states the 2000W Modified Sine Wave Inverter is for powering game players, laptops, car vacuums, TVs, refrigerators, DVD players, flood lights and microwave ovens etc.
This inverter also comes in a 1000W version for powering equipment that requires less power.
If you determine that your equipment is too sensitive to use a modified sine wave inverter, you may want to invest in a 2000W PURE Sine Wave Inverter.
How do I connect my travel trailer battery to my trailer’s electrical system?
How to connect travel trailer battery in 4 easy steps.
Step 1: A deep cycle travel trailer battery usually comes with two threaded terminals with wingnuts on them.
One will be positive indicated by a plus (+) sign and the other will be negative indicated by a minus sign (-).
Step 2: The RV will usually have two cable leads with eyelets/lugs … one will be red which is positive, the other will be black or possibly white which is negative.
Step 3: How to connect the RV battery safely begins with proper polarity.
Connect the positive RV cable lead → to the positive RV battery terminal.
You do this by placing the RV cable eyelet over the threaded RV battery terminal and then tightening the wingnut to hold the cable securely to the RV battery terminal.
(Note: it is important to connect the red positive power lead before connecting the black or white negative ground lead. In other words, don’t do step 4 prior to doing step 3.)
Step 4: Now … connect the negative RV cable lead to the negative RV battery terminal by using the same method (described in step 3.)
Blade Car Fuses Assortment Kit Standard And Mini
If you mistakenly cross connect the positive and negative leads … you will surely know it.
This will cause sparks not soon to be forgotten.
You will probably find blown fuses on your RV’s electrical panel.
This is one good reason to have an Assortment Of Various Sized Electrical Fuses … just in case.
Yes, we speak from experience here … ugh!
Should I disconnect my travel trailer batteries?
How to disconnect travel trailer battery and when you should do it.
It is best to keep your deep cycle RV battery charged to prolong its lifespan.
RVs have components (like the FM radio and LP gas alarm) that are hard-wired and may discharge your camper battery even when it is just parked in storage … this is called parasitic draw.
In order remedy this unwanted battery drain, you must isolate the battery from the RV electrical system.
To disconnect the travel trailer battery from your camper, you can reverse the process listed above … starting by disconnecting the negative terminal first.
If you want to make the process easier, you can install a battery quick disconnect switch like this Top Post Battery Master Disconnect Switch and then all you have to do is turn the knob to disconnect the battery from your RV.
This method is really convenient for people who take their RVs in and out of storage frequently and want to avoid the potential of drawing their RV battery down by hard-wired components in their travel trailer.
Why is my RV battery draining?
Any type of battery will self-discharge over time.
BUT, if your RV battery is draining beyond this normal slow self-discharge rate, it is because something is drawing power.
Some components in your RV’s system are hardwired directly to the battery and do not have an on/off switch.
Even if you have every electric accessory in your RV turned off, if your battery is draining that means there is something drawing power that will eventually draw down your battery.
Here is how you can tell if that is happening: verify every electrical item in your RV is switched off … when you connect the RV lead to the battery … notice if any spark occurs when the connection is made.
If there is a spark, something is drawing a load.
That means you have hard-wired electric components that are drawing a parasitic load … this is not unusual with components like LP gas detectors, hot water heater circuit boards and monitor systems etc.
To remedy unwanted battery draining, you need to totally disconnect your RV battery from your travel trailer as described above.
Because RV batteries self-discharge over time, you’ll need to fully charge the battery before your next camping trip if it is really low.
If it just needs to be topped off, it will get recharged when your RV is connected to your tow vehicle while driving to your camping destination.
What charges a travel trailer battery and does RV battery charge when plugged in?
How to keep travel trailer battery charged is simple.
Your travel trailer RV battery will recharge when it is plugged in to an AC outlet.
This is accomplished with a DC converter/charger that is typically located behind your circuit breaker panel.
It converts 120 volt AC shore power to 12-volt DC power to charge your RV battery as well as power all the 12-volt DC components.
There are different types of converters. The best RV battery converter/charger is a Three-Stage Charger that will not overcharge your battery.
You choose the setting for the type of battery system you have (flooded, gel, or agm) then as the battery is charged and the battery voltage is increased … the converter/charger steps down the voltage being supplied to the battery in order to avoid the battery being overcharged.
This style of RV smart charger is the best RV battery charger because of its ability to provide a safe multi-stage charge.
Your travel trailer battery will also be trickle-charged when you are towing your RV.
The DC power runs directly from your tow vehicle through your 7 Way RV Plug as you drive to camping destination.
Methods of keeping your RV battery charged
The type of power sources available determine how you can keep your RV battery charged. Here are 5 common options:
Option 1: Plug the main travel trailer electrical cord into a 120 volt AC outlet at a home, RV park or some other location with shore power.
This will power the converter/charger located behind the circuit breaker panel … which then powers all of the DC components (like lights) in the RV.
This method turns AC into DC and charges the travel trailer battery too.
Option 2: Tether a 3 or 4-Stage Smart Trickle Charger directly to the terminals of the RV battery to recharge it.
You plug the trickle charger into a wall outlet … then connect the two charging alligator clips directly to the RV battery terminals.
This will recharge the RV battery … keeping it connected will maintain a top-charge on your RV battery.
Option 3: If you have an onboard generator, you can use it to recharge your RV battery system.
If you don’t have an onboard generator, you can use a portable generator to keep your RV battery charged.
This is one of the most common methods of charging your RV battery system when you are camping in an area without shore power (aka boondocking).
You just plug the travel trailer’s power cord into the AC outlet on the generator and run the generator until your RV battery system is charged up to the desired level.
This can be done with a Super Quiet, CARB Compliant Small Suitcase Style Generator.
Option 4: If you want to use the generator to power your RV’s air conditioner, you’ll need at least a 3400-Watt Generator … the inverter type generators of this size are nice because they are really quiet, safe for computers and many have duel-fuel options.
Option 5: Hook up solar panel for RV battery charging to produce DC power to the travel trailer battery.
Make sure that the RV solar battery charger is properly regulated so they don’t overcharge the RV battery.
This Renogy Solar Panel Set has a 20A built-in 5-stage solar charge controller which provides overcharge protection.
It is also nice because it folds for easy storage and comes with a protective case.
What is the lifespan of a travel trailer battery?
How long a flooded lead-acid RV travel trailer battery will last depends on two main factors: the climate you live in and how well you maintain it.
Extremely cold climates are tough on RV batteries because cold weather can slow down the internal chemical process inside the battery that generates electricity.
Extremely hot climates are even worse on RV batteries because extreme heat can increase the amount of sulfates on the internal plates thus reducing the battery’s life.
If you consistently overcharge or undercharge your RV battery, you will shorten its lifespan.
Typically you will get about 3 – 5 years and 400 cycles out of a good flooded lead-acid RV battery with proper care and maintenance … but, if you are using a lithium RV battery it has a lifespan of generally up to 10 years and approximately 5,000 cycles.
Here are more RV battery maintenance tips and how to check travel trailer battery:
If you are using a flooded lead-acid RV battery, keep the water levels up … especially in the summertime.
Check your RV battery periodically by removing the caps to see the water level … it should cover the plates in the battery.
If the level is low, you’ll need to add distilled water to a level that covers the plates.
If your RV battery state of charge is low, and you leave it at that level, it will reduce the lifespan of the battery.
You want to recharge a low battery as quickly as possible.
Recharging a discharged battery as soon as possible will extend the lifespan of your deep cycle RV battery.
If your battery voltage is reading below 12 volts … your battery is half dead … in other words, it is less than 50% state of charge.
Technically, if you leave an RV battery at a low state of charge … sulfate crystals build up on the charging plates … that reduces the battery capacity and its ability to accept a full charge … eventually, the battery will fail and need to be replaced.
If your RV battery state of charge is high but less than full, keeping it charged using a 3 or 4-Stage Smart Trickle Charger is good and will help increase the life of the battery.
You can check the power level of the battery with a Voltmeter … even though it is called a 12v RV battery, when the battery is fully charged, you should see about 13.4 volts on a deep cycle flooded lead acid RV battery.
Pressing the battery test button on the RV’s Monitoring System inside the trailer provides a rough estimate of the level of available RV battery power.
Being prepared for an after-dark setup is one reason you want to make sure your RV battery is in tip-top shape!
Check out our RVing Tips For Beginners: Enjoying The Maiden Journey post for more helpful information.
How long will RV battery last boondocking?
An RV battery can last quite a while when you are boondocking if you conserve on your consumption and your RV battery system is healthy and properly charged.
If we are NOT recharging our RV battery system while using it, we typically get 5-7 days out of our dual group size 24 deep cycle RV battery set while boondocking.
There are a few things to consider when boondocking and using your RV batteries as your main power source. Questions to consider:
- What is the total amperage and condition of your RV battery system?
- How much load are you placing on the camper battery system?
Questions to ask yourself about the electrical load you are demanding from your RV battery:
- Are you using inefficient incandescent light bulbs or efficient LEDs? Learn more about this in our camping lights post.
- How much are you running your water pump?
- Are you running your heater motor?
- Are you operating electric slides and awnings?
- If you have an external ventilating fan on your propane RV refrigerator, is it constantly cycling on and off?
- Are you watching your RV TV and listening to your RV stereo?
- Are you charging your personal electronic devices?
If you are keeping your RV battery system topped off with solar panels while boondocking, your batteries can last indefinitely with enough sun and large enough solar panels.
Here in Arizona, our 100 Watt Renogy Solar Panels keep our RV battery system topped off with a moderate demand of normal camping power requirements plus our personal electronic devices we use for our blog including phones, ipad, laptop computer and cameras.
If you need boondocking tips, check out our Boondocking: How And Where To Go Dispersed Camping post … no matter what time of year you are camping in the wild!
Will my RV battery run my refrigerator?
The relationship between your refrigerator and your RV battery
In most cases, an RV battery will not run a standard RV refrigerator but there are some exceptions. Here are a few things to consider:
Residential-style refrigerators are found in larger RVs and only operate by 120 volt AC power source from a standard wall outlet.
For RVs with high-capacity battery banks, you may be able to draw power off of the inverter at a high enough volume to run a refrigerator but those are rare when it comes to normal RV systems. These are typically found in larger motorhomes.
Typical Dual Power RV Refrigerators can run on propane gas or electric.
These units require too much power to operate using an RV battery … you need to plug these refrigerators in to a 120 volt AC wall outlet using shore power or a generator … if that is not available, you must run these refrigerators using propane but if you are running on propane you still need electricity from your RV battery to operate the control circuit of the refrigerator system.
Small Camper Refrigerators have low enough power requirements that they can be operated using an RV battery as a power source.
These undersized refrigerators have a very small capacity, are powered by DC cigarette lighter plugs and are not commonly found in most travel trailers.
What is an RV battery isolator?
An RV Battery Isolator is a switch that connects the battery terminals to the RV electrical system.
The purpose is to easily open and close the electrical connection between the RV and the battery without having to remove the actual terminal leads from the battery itself.
You always want to disconnect the battery to prevent it from draining when your RV is not in use or parked in storage.
Why is my RV battery boiling?
Your RV battery is boiling because it is overcharging.
When a battery is overcharged, it heats up and can boil over … this boiling occurs because it is actually steaming off the water in the battery.
The byproduct of this overcharging condition is hydrogen gas which is dangerous and may cause an explosion.
Why would my RV battery explode?
Most RV batteries are the deep cycle flooded lead acid type which contains electrolyte. Explosive hydrogen gas is a byproduct of normal RV battery charging.
There are 2 reasons your RV battery may explode:
- The first is excessive pressure in the battery case itself. Even though hydrogen gas is a byproduct of normal charging, it does not create a dangerous environment because it vents out easily from the top of the battery. BUT … during overcharging, if the battery is not vented properly, the gas pressure builds up reaching dangerous levels, exceeds the venting capability of the RV battery case and pops like a balloon spewing corrosive acid all over.
- The second is hydrogen gas igniting. This explosive condition can occur anywhere the vented hydrogen is trapped even in the battery compartment if an ignition source is present. That is what happened during the Hindenburg disaster that occurred on May 6, 1937.
Which is better for my travel trailer: RV inverter generator or generator?
An inverter generator provides a more stable power source for the RV than a normal generator and will not damage sensitive equipment such as computers.
Check out our Best Quiet Generators For Camping post for more information as well as our power requirement calculator to help you determine what camping generator is best for your needs.