Best RV Battery (Deep Cycle) for 2021: Your Complete Guide

Photo of an RV for the best RV deep cycle battery article
There's nothing more liberating than traveling around in an RV.

Apart from the cool factor and cost savings, you get the convenience of bringing some comforts of home with you wherever you travel. You can plug in literally anything you want, from a toaster to a washing machine (not that you would!)

It’s the flexibility to travel the way you want it. That definitely beats out first class airplane seats in my book!

However, loading appliances here and there can quickly add up on your RV’s energy consumption. Pretty soon, you’ll have a power hungry rig in your hands that will take a small nuclear plant to run.

You therefore need to carefully consider and invest in the best RV deep cycle battery for your needs. Doing this ensures that you enjoy your RV trip the way you intend to, without any nasty power interruptions.

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But First, What's an RV Deep Cycle Battery, Anyway?

To begin answering this question, you first need to know the kind of batteries an RV needs.

For an RV to function, it needs two types of batteries – one to start its engine if it needs to move, and another to continually power all the appliances and gadgets it has onboard.

To fire up the engine, you need a battery that can supply a massive burst of electricity in a short amount of time. These are called starter batteries, and most car, motorcycle and other automotive batteries fall in this category.

To power your RV’s appliances and other functions, on the other hand, it needs a battery that can provide a constant stream of electricity over more extended periods, recharging and discharging as it goes along.

Starter batteries, unfortunately, do a piss poor job in this regard. Even though you technically can use it this way, we highly discourage it. The repeated charging and discharging would quickly break down the battery faster than you could say, “That was a bad idea!”

You need to invest in something a little more robust. Enter the deep cycle battery.

Deep cycle batteries are made specifically for constant charge and discharge cycles. They’re sturdier, larger and made of thicker plates, which makes them far more efficient at storing and releasing charge than a starter battery.

RV batteries are charged through a power source, such as a charging station commonly found in parks. An important thing to note, though, is that RV deep cycle batteries supply 12V DC power to your rig. Outlets in charging stations, on the other hand, give out 120 AC. 

Make sure you have a power converter installed before plugging in to prevent any catastrophic damage to your battery.

It is important to know that a deep cycle battery's maximum capacity drops once it has reached its rated number of cycles. Since RV deep cycle batteries are an RV battery, the type and size of features to look for are different compared to a typical vehicle battery.

Deep cycle batteries of the highest quality normally hold up for ten to fifteen years before losing maximum capacity, while the worst might only hold as much as a year or two of their stated capacity. It's important to think about how your battery will be used when choosing the right one for your motorhome or travel trailer.

If you’re like most RV users and enjoy having a few appliances plugged in for your convenience while on the road, then you definitely need a decent deep cycle battery powerful enough for your setup.

A Quick Guide on Buying the Best RV Deep Cycle Battery

More than any vehicle, you need to buy an RV deep cycle battery that is very specific to your usage.

Different RV users have wildly differing power needs. Some like it simple with nothing but lights at night. Others want to bring in every conceivable appliance from their house – power consumption be damned!

So it’s essential to know when, where and how you're going to use your RV – and every piece of appliance in it.

As always, research and planning are your best friend. You need to do your homework, or your risk cutting your RV trip a little short.

So what are the essential things to consider when out buying an RV deep cycle battery?

How much power do you need?

This is probably the #1 factor to consider when getting an RV deep cycle battery. As stated above, how much power you need is directly proportional to the number of onboard appliances you plan on using.

You need an RV deep cycle battery with a large enough capacity, which is measured in Amp Hours or AH. AH tells you how much current (or amps) the battery can deliver over a set period (defined in hours) before it’s fully drained or discharged.

A battery with 100 AH, for example, can power up 10 amps worth of appliances for 10 hours. The higher the power consumed, the faster it discharges. So a 50-amp consumption will only last that same battery 2 hours before being fully discharged (or, mathematically speaking, 50 amps x 2 hours = 100 AH)

However, it's not a good idea to drain your battery down to 0%, or else you risk shortening its life. Manufacturers and experts advise never to let your battery's capacity drop below 20%

So you need to factor this in when choosing a proper AH rating for your RV deep cycle battery. In practice, this means that your usable AH is only 80% (i.e., for a 100 AH battery, your maximum consumption is only at 80 AH) before you need to recharge.


How to Measure Your RV's Power Consumption

As you can imagine, having a very accurate picture of your daily amp usage is critical to inform your buying decision. For this, you need to take every piece of appliance in your RV and determine two things: how much amp it consumes per hour and how long you plan to use it for, on average.

First, make a list of every appliance you have onboard (an Excel sheet comes in handy). The amp usage and other information are usually stamped somewhere in the product or box, or you can consult your user manual if you have it. Worst case, you'll find what you need online.

Can’t see an amp rating? You can take the stated watt and voltage rating and get the amp per hour rating using the formula:

watts / voltage = amps

So an appliance with 100 watts and 12 volts roughly consumes 8.3 amps per hour (100 watts / 12 volts = 8.3 amps)

After you’ve determined your amp usage for all your appliances, you need to think about how often you use each of them in a day. You can calculate it using this handy formula:

amps per hour X hours used per day

For example, let’s say the 4 lights you have in your RV need 0.3 amps/hour each to run and you use them for 8 hours. Your daily AH consumption would then be 9.6 amps per day (4 lights X 0.3 amp per light X 8 hours = 9.6 amps per day)

In the same way, a 10 amp per hour device used for only 15 minutes will lead to a daily drain of 2.5 amps per day (15 minutes being ¼ of an hour X 10 amps = 2.5 amps per day)

Finally, it’s a matter of adding up the amp per day consumption of all your appliances to get your daily AH usage. Simply add 20% to this number, and you have the minimum AH for the RV deep cycle battery you need to get.

(Whew! That was one long but necessary explanation – good job for sticking through!)

Do you plan on going off-grid?

After power consumption, another thing influencing how much AH to get for your RV deep cycle battery is your decision to go off-grid.

Going off-grid simply means operating your RV without connecting to an external power source. Off-grid gives total freedom to some RV user, and more are frequently doing this.

How is this relevant to you?

If you plan to disconnect from any power source for a significant amount of time, you need to make sure you have enough reserve power to last you through. Get an RV deep cycle battery that has the biggest AH rating you can afford. 100-125 AH is a number to target.

On the other hand, if you find yourself having a constant source of power, then you can get away with a much lower AH rating. A minimum of 30-50 AH RV deep cycle battery should suffice.

Do you plan on using a dual-purpose RV deep cycle battery?

Dual-purpose batteries combine the best of both worlds – the cranking power of starter batteries and the repeated charge/discharge abilities of a deep cycle battery. But do you need it?

The obvious benefit is cost. In some cases, it’s still cheaper to get a dual-purpose battery than to get a starter and a deep cycle battery each. You also get the benefit of charging while the RV is running, without the need for a power source.

However, keep in mind that the capabilities and amp output of a dual purpose are still far less than that of a dedicated starter or deep cycle battery. If you’re operating a low-consumption rig, then a dual-purpose battery can give cost savings and might be a good idea.

What’s the weather like in your area?

Or you can extend this to “what the weather is like in the area you intend to bring your RV to.” Extreme temperatures can affect your RV deep cycle battery’s performance; so make sure it can operate in the proper range. Cold weather is especially challenging, so make sure your battery is up to par!

Going for a rough ride?

While not as tough as an ATV battery, RV deep cycle batteries still need a fair amount of durability and shock resistance. After all, you're taking your RV out in the open, and there's no telling what terrain you'll encounter.

Aim for a spill or leak free construction and shock absorption. This saves you the trouble of messy topping up or repairs, should your batteries get damaged in transit.

What type of RV deep cycle battery is best for your needs?

There are many different types of RV deep cycle batteries available, but some are better than others.

Traditional lead-acid batteries, or what's called flooded cell, are the most common type and generally the cheapest option. They perform quite well and are more than suitable for an RV. Their major drawback pops up come maintenance time – they need to be regularly topped up with water to ensure proper operation. Forget this, and you're looking at a ruined battery.

If you’d rather not mess around with that, go with maintenance-free lead acid batteries, such as gel or AGM. Of the two, AGMs perform better for use as an RV deep cycle battery. While gel batteries need to be charged at a lower rate and voltage, AGMs are not stopped by such limitations.

For the best performance, you can’t go wrong with lithium-ion batteries. They charge a hell lotta faster, weigh so much lighter and hold much more capacity than lead acids. The thing is, they’re also much more expensive. If you can afford it, go for it.

Lithium batteries degrade over time at a slower rate than lead-acid batteries, so they have a longer life cycle. Unlike lead-acid batteries, lithium batteries will deliver full power even when the cells' energy levels are depleted. They run more electrical equipment in your RV for longer periods of time. A disadvantage of lithium batteries though is a lack of performance in extremely cold temperatures.

How long do you want your RV battery to last?

Of course, we want them to last forever. But that's not entirely realistic, isn't it? On average, you should expect a battery to last an average of 8-10 years with proper maintenance.

Regularly discharging and recharging it, but not letting it drop below 20% capacity, is key to a battery’s lifespan.

Also, consider the warranty when shopping for a battery. Warranties are important! They are an excellent insurance policy, should you get a battery that doesn't quite work as it should (and it happens quite a lot).

Our Roundup of the Best RV Deep Cycle Batteries for 2019

Even with your newfound knowledge of RV deep cycle batteries, it can still be challenging to find the right one for your needs. So we’re here to help you out with our top picks on the best RV deep cycle batteries of the year.

Let’s do a deep dive into our options, starting with:

Best performance RV deep cycle battery is the VMAX SLR125 AGM Deep Cycle Battery


VMAX SLR125 AGM Deep Cycle Battery (125 AH) 

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The VMAX SLR125 AGM Deep Cycle Battery should be your top choice if you’re looking for a winning combination of performance, price, and durability.

First impressions definitely last, and our initial opinion when we got the VMAX SLR125 out of the box is how durable it feels. The outer shell is of solid construction, and the plates themselves are made out of military-grade metals. VMAX claims this is a battery that can live for 8-10 years, and we're inclined to believe that assessment.

You’d have no worries taking this out for a spin – rain or shine, hot or cold. It could easily survive a drive down a rugged off-road path. The fact that this deep cycle battery is also made for use in boats is a testament to its toughness.

And did we mention that it’s heavy? This is one hefty 75 lbs RV deep cycle battery. On the one hand, it gives the impression that it has a massive capacity and means business. On the other, it can be a challenge to lift and install. But how often do you need to do that? 

Performance wise, it boasts an impressive capacity of 125 AH, more than enough for a few days off-grid. The VMAX SLR125 is an excellent option if you're looking for a high capacity battery. We hooked it up to our rig setup and handled the almost 90+ AH power drain effortlessly.

Being an AGM battery, it charges pretty fast and is maintenance free, which is a nice bonus.

Overall, the VMAX SLR125 delivers reliable performance and can easily protect itself from the toughest of conditions. The price point isn't bad either, which further makes it a must buy.

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Extended service life of 8-10 years gives a solid return on money
Charges faster than comparable lead acids, and is maintenance free
12-month warranty
Very heavy and can be challenging to install for some
The best budget RV deep cycle battery is the Interstate DCM0035 35 AH battery


Interstate DCM0035 (35 AH)

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Marrying dependability and durability at an affordable price, the Interstate DCM0035 is an RV deep cycle battery that can stand side by side with its bigger cousins.

If you're discouraged by the small size of the DCM0035, don't be. This is a stellar and well-built battery made for deep cycle applications. Being more modest, it's also easier to carry around and install, plus it achieves full charge faster than bigger batteries.

The only thing with the DCM0035 is its smaller AH rating. At only 35 AH, it’s certainly on the low end, especially with today’s power hungry RVs and appliances. In this case, you can just aim for lower consumption, and it will work out fine.

Still keen on getting the DCM0035 but need a higher AH rating? Consider getting a few and hook them up in a series. In essence, you’re trading off the affordability with a higher capacity at the same quality and durability you’ll get with Interstate batteries.

Overall, the DCM0035 offers exceptional value at an equally fantastic price. If you're running a bare-bones setup with minimal consumption, or if you don't plan on going off-grid at all, then this is a fantastic pick, bar none.
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Sturdy construction
Its small compact size makes carrying and installing easy
Very affordable
Flexible and can be used in a variety of applications
Not designed to be used off-grid or by power-hungry RV rigs
The best budget ATV battery is the Upstart Battery UB-YTX12-BS


Universal UB121000 (100 AH)

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For the RV user wanting a hassle-free off-grid experience, few can top the capacity and quality of the Universal UB121000.

At its core, the UB121000 is a hardworking AGM deep cycle battery. It's leak and maintenance-free, so it makes it a joy to use – just set and you’re good to go. Its shock and vibration resistant as well so these can withstand the normal bumpiness from a typical RV ride, maybe more so. 

The UB121000 provides a robust 100 AH capacity, great for powering an RV off-grid with the extra conveniences. We tested it out when we camped out, and it ran our lights and radio for the duration of the weekend. The amazing part is it’s still relatively full!

But probably the great thing about this RV deep cycle battery is it’s such a great deal. It’s a mid-range priced battery that provides high-priced performance. That’s value for money right there!

If you plan on going off-grid and want to invest in a reliable battery that won’t break the bank, get the Universal UB121000. An RV is already expensive as it is – best not deepen that hole in your pocket any further!
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Reliable 100 AH battery perfect for going off-grid
Maintenance free operation
Great value for money at a fantastic price
12-month warranty
Short stainless steel hardware can make connection a bit harder
The best high powered ATV battery is the Yuasa YTZ10S


Optima Batteries 8052-161 D31M (75 AH)

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The Optima 8052-161 D31M is a fusion of the high cranking power of a starter battery and the charge capacity of an RV deep cycle battery. In other words, it’s a true dual-purpose battery. What this means is that it can both supply the necessary AH to power your appliances, plus a burst of cranking amps when you need to start the engine.

At the heart of the Optima 8052-161 D31M is its unique Spiralcell Technology. Instead of using flat plates, their batteries use two lead plates arranged in a spiral. This translates to more rapid charging, higher power capacity and greater resistance to vibration.

Or in other words, better overall performance and longevity compared to other AGM batteries.

As a starter battery, the Optima 8052-161 is capable of dishing out 900 CCA, more than enough to properly start your RV. Deep cycle wise, it can store and discharge up to 75 AH, making it perfect for RVs with mid-range consumption.

All in all, the Optima 8052-161 is perfect for RV owners who just want to deal with one battery. If your camping out for long periods at a time and use your deep cycle battery more than your starter battery, then this dual-purpose option makes sense.
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Combines starter and deep cycle batteries into one convenient and powerful package
Unique Spiralcell technology leads to better battery performance and vibration resistance
Reserve capacity of 155 minutes ensures uninterrupted output.
Maintenance free operation
Its AH rating is lower than other deep cycle batteries in the same price range
The best lithium ATV battery is the MMG4 YTZ14S


Battle Born Batteries LiFePO4 (100 AH)

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If you’re in it for the long haul and can afford the price tag, then the Battle Born 100 AH Lithium Iron Phosphate Deep Cycle Battery is the last battery you’ll ever need.

The Battle Born is a step up on virtually every other lead-acid and AGM batteries. Right away you’ll notice that it’s very lightweight (around 29 lbs), or roughly 1/3 the weight of comparable AGM batteries of the same power class.

But if you think to be light means having less power, think again!

Performance wise, this battery is top notch. Where to begin? It discharges a continuous 100 AH, with a powerful 200 AH burst should it need to for higher loads. It also charges incredibly fast, making the most of your charging stops when out in the road.

LiFePO4 batteries can also be safely discharged up to 90% of their total capacity without any lasting damage. This allows you to maximize your battery's capacity fully, unlike lead-acid batteries.

And did we say these things can last you a lifetime? LiFePO4 batteries are built for 3000 charge cycles, 10 times more than the standard lead-acid battery's cycle of only 300. You’re looking at a lifespan of over 20 years at the minimum!

Of course, a powerful battery such as this doesn’t come cheap. However, the extreme performance and ridiculous service life offer a great return on your investment in the long run.

For the most serious RV owners who want a powerful and long-lasting battery (and have some money to burn), then the Battle Born 100 AH LiFePO4 battery is one of the best batteries you can buy.
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Incredibly powerful battery at 1/3 the size and weight of comparable lead acids
Capable of lasting 3,000 charge cycles, making it last 10 times longer than lead-acid batteries
It can safely discharge up to 90% capacity, giving you more usable AH vs. other AGM batteries.
8 YEAR full replacement warranty!
Very high upfront cost

Final Thoughts

RVs give owners like you the total freedom to load it up with whatever appliances you can dream of. While this is cool and all, having the right RV deep cycle battery for your needs is a crucial first step to make sure everything functions without a hitch.

If you give your RV want it needs, it’ll reward you with years of memorable and liberating travels. So get the best RV deep cycle battery for you today!

We hope our guide has helped you in your quest for a better riding experience!

Frequently Asked Questions:

What is a deep cycle RV battery?

Deep cycle RV batteries are designed to discharge to their maximum capacity. Because they have thicker plates, they can discharge deeply and recharge repeatedly. So they can offer a steady amount of current for a prolonged period. RV batteries (that supply at least 12-volts or more) should ideally be deep cycle batteries.

Is there a difference between deep cycle and marine battery?

Yes, there's a difference between the two batteries. Deep cycle batteries have thicker plates that allow them to discharge down to 80% or more. Marine batteries are hybrid batteries that can be a mix of starting batteries, dual-purpose batteries, and in some cases, deep cycle batteries. Marine batteries have plates that are thinner than deep cycle batteries.

What size batteries do I need for my RV?

Sizes vary but it should be approximately 181 x 76 x 166 mm in dimensions. If you're selecting deep cycle batteries, then you should get a 12-volt battery. Starting batteries tend to be similar in size and voltage. Refer to your RV manual for more guidance on the battery size.

How long does a deep cycle RV battery last?

Some deep cycle RV batteries last only 2 years while others can last for up to 6 years. It depends on the manufacturers and several other factors. Also, if you're deeply discharging it a few times per week, it will last longer. You should ensure that the battery doesn't get damaged due to your handling.

Does a deep cycle battery need a special battery charger?

Yes, it's recommended to use the charger that the battery company offers you. There's a separate charger for flooded, AGM, and GEL variants. Use the specific charger for a particular battery. Charging with regular chargers is possible, but it's not recommended since they can shorten the battery life. Moreover, they can produce excess heat.

How long should a deep cycle battery hold its charge?

Normally, 12-volt deep cycle batteries tend to last 20 hours or less depending on your usage. You have to refer to the amp-hours of the battery. If it states 90 amp-hours, then, in theory, it would supply one amp for around 90 hours. And practically, that's less than 90 hours.

Can you overcharge a deep cycle battery?

Yes, you can overcharge any battery, and deep cycle batteries aren't an exception. If you exceed the amp-hours, you're essentially overcharging your battery. If you're charging on high voltage, then you're overcharging your deep cycle battery as well. It can lead to grid corrosion and reduce battery life.

How do you test a deep cycle battery?

You can measure your deep cycle battery using a multimeter. It can measure the voltage when you connect it to the battery. A fully charged battery should have the said output voltage, which can be 12 volts, 13 volts, or anything else. If the readings drop one volt or two when you retest, then it's perhaps a faulty battery.

Should RV batteries be series or parallel?

It depends on whether you're using a 12V RV battery pr 6V. In the case of 12V, you need to wire them parallel to increase amp hours while keeping the voltage same. If you're using 6V batteries, then wire them in series to achieve the desired voltage. Refer to the manual for guidance.

Why Is My RV battery draining so fast?

Things like dome lights and headlights drain your RV battery faster. If your RV is consuming too much electrical power, then your battery will drain faster. When your RV is at rest, consider disconnecting the ground wire which would prevent the battery from draining when it's not in use. Also, check for leakages if your battery is draining fast.

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