Deep Cycle Battery Buying Guide

See below for more Deep Cycle Lithium Iron Phosphate Battery Recommendations like the ones featured above.

Whether you’re embarking on a multi-week journey or an extended weekend jaunt in your rig, you’ll have a million different things to worry about — battery maintenance shouldn’t be one of them. With a properly designed and assembled power management system, peace of mind will ride shotgun along the trek. At the core of this system is the battery. Start with a high-quality battery sufficient to meet the needs of your set-up, and everything else will fall into place. 

With a seemingly endless array of battery choices before you, how do you know what’s high quality and what’s just junk? How do you make an informed choice without spending hours upon hours weeding through YouTube videos and online reviews? We’ve done the dirty work for you. Use this guide to understand what to look for in a battery and see which batteries rise to the top of our list. 

Battery Basics

Deep cycle batteries fall into one of two primary categories: lead acid or lithium ion. The basic mechanics within these batteries are the same, the chemicals and materials used to achieve the results are what differs. Before we discuss the differences between the two, let’s quickly recap basic rechargeable battery mechanics. Batteries operate through a repeating cycle of oxidation and reduction, where electrons travel between two metals (from the anode (-) to the cathode (+) during battery use and from the cathode (+) back to the anode (-) when recharging via an external power source). Over time the battery becomes less efficient in this process and ultimately die and require complete replacement. Check out this TED-Ed video for a better explanation of rechargeable battery basics:  

Starter vs. House Batteries

When you’re traveling the country, chances are there’s a slew of energy-consuming devices you’re bringing with you: refrigerators, cameras, laptops, tablets, lights, fans, to name a few right? Relying on your vehicle’s (aka “starter”) battery alone to power these devices is a short order for disaster.

Starter batteries are specifically designed to produce large bursts of power to start your vehicle, then relinquish power responsibilities over to the vehicle alternator. While your vehicle runs, all the accessory devices you’ve got hooked up can charge.

Turn the vehicle off, and suddenly your starter battery is on the hook for powering those devices. Before you know it you’ve got a dead battery and a pickle of a situation. 

That’s where house (aka “auxiliary”) batteries come into play. Installing a good-quality deep cycle house battery is an excellent way to divy up your power needs so that your starter battery can focus on its job without the burden of feeding accessory device power needs.

Arranged in the right dual-battery system and you’ll have both the starter and house batteries working together so that you’ll have enough power where and when you need it. 

What is a Deep Cycle Battery?

Simply stated, a deep cycle battery is one that can withstand deeper discharges of power repeatedly and for sustained periods of time.

They’re ideal for supporting devices that require a consistent, continuous power supply such as camp refrigerators, lighting, water pumps, etc. Starter batteries can only handle small power discharges before relying on the vehicle’s alternator for recharge. 

Types of Deep Cycle Batteries 

For decades, lead-acid batteries were the only option available. Since lithium batteries came on the market they have steadily chewed their way through the competition, especially as advancements in technology have resulted in safer, more efficient, and more cost-effective options.

With lead-acid batteries, you get two types to choose from for deep cycle options. Of these two, the lead-acid SEALED AGM battery is the most prevalent for use as a house battery. With lithium-ion batteries, the LiFePO₄ is the go-to option for deep cycle house battery use. 

Choosing Your Deep Cycle Battery 

Answering two crucial questions will steer you toward a good battery purchase decision: price and compatibility.

PRICE

• Significant differences in price separate lead-acid and lithium batteries where lithium batteries are often two to three times more expensive.

• Though the upfront price for lithium is considerably higher, they’re ultimately more affordable and efficient in the long run because they simply last much longer.

• Just as lithium batteries are up to three times more expensive, they last up to three times as long. 

COMPATIBILITY

If you intend on setting up a dual battery system, the battery you choose for your house system must match the type of battery you use as your starter. That’s unless you use a battery management system (BMS) to control power flow to your batteries, which in this case, you can use any type of battery combination you like. (If you don’t use a BMS, you’ll still need to install a solenoid to prevent power drainage of your starter battery. Michael from Overland Bound has an excellent YouTube tutorial on setting up an inexpensive dual battery system this way. 

Other Factors to Consider

Next to cost and compatibility, you may want to keep factors in mind like weight, size, vibration resistance, cycle life, and toxicity. We’ve rated flooded lead-acid, AGM lead-acid, and LiFePO4 lithium iron phosphate batteries to give you an indication of what you may expect in these categories from each battery type. Of course, each of these dependencies varies from specific battery to battery, but this will give you a ballpark idea. 

*comparisons based on a 100 Ah 12 V battery

Choosing a Deep Cycle Lithium Iron Phosphate Battery (LiFePO4)

While lead-acid batteries like AGM have been around for some time, are pretty straightforward in construction, and hover around the same low price point ($200 to $300), lithium iron phosphate, the most popular of the lithium-ion class of deep cycle batteries, is a whole different story — or shall we say… novel. There are a few characteristics you can expect with a lithium iron phosphate (LiFePO4) deep cycle battery: it will be more expensive than a lead-acid, it will last around three times as long as a lead-acid, and its allowable discharge will be twice that of lead-acid. What you cannot expect from any LiFePO4 battery is quality construction; quality varies wildly among manufacturers. Here are some key factors to keep in mind when selecting a LiFePO4 deep cycle battery.

1. Price

   Generally speaking, LiFePO4 batteries that are unbelievably low-priced are too good to be true. These batteries are manufactured in factories that typically do not give the same level of care and attention as outfits that design and assemble their own batteries themselves. Exceptions to this rule of course exist — but this is something to keep in mind. If you’re ever in doubt, take a look at the manufacturer’s website. If it clearly states where or how the batteries are produced, like Battleborn does on their site, you may have a smidge more confidence in your purchase.

2. Serviceability

   Serviceable batteries are those you can pop the top off (in some this is easier said than done) and replace select battery cells when needed. As LiFePO4 batteries have a 10 to 15-year shelf life, you shouldn’t have to do this very often. The hidden bonus in purchasing a serviceable battery like an SOK or a Lion Energy is the honesty factor. Manufacturers of serviceable batteries would be dumb to cut corners because you - the consumer- can see exactly what they’re up to inside the battery. There’s no hiding shotty craftsmanship or poor design.

3. Low-Temperature Cut-Off

   Charging lithium batteries in below-freezing temperatures is bad for the battery. Nearly all LiFePO4 battery manufacturers recommend charging at temps between 32 and 110 to 140 degrees Fahrenheit. If you’ll be using your battery in cold conditions at any point, purchase a battery with a low-temperature cut-off.

4. Warranty

   Deep cycle LiFePO4 batteries are two to three times as expensive as lead-acid batteries of equal capacity. Even with the best design and constructions, things go wrong every once in a while. Purchasing a battery with at least a five-year warranty gives that insurance that you won’t be throwing $500 to $1000 dollars down the drain. Antigravity, BigBattery, and Weize are manufacturers that provide a 10-year warranty on their deep cycle LiFePO4 batteries. Lion Energy provides a limited lifetime warranty on their LiFePO4s.

Best Deep Cycle Batteries (Lithium]

That old adage “never judge a book by its cover” couldn’t be more true in the world of deep-cycle lithium iron phosphate batteries. (For this guide, we did not review AGM or Gel batteries.) As off-grid power expert Will Prowse and many like him have mentioned in their battery reviews and discussions, a chasm of cheapness and shotty craftsmanship separates the good from the bad LiFePO4 batteries. The internal construction of the battery is paramount to a battery’s dependability and longevity — something you should never take a chance on when the battery you choose will serve as the lifeblood for your rig. We paid close attention to what Will and other experts found when they ripped apart popular LiFePO4 batteries on the market today to help create our list. Any battery that revealed less than solid connections, reliability, or construction did not make our list. What did make our list were quality LiFePO4 batteries at varying price brackets and features. 

For this review, we only examined and rated 100Ah 12V LiFePO4 (Lithium Iron Phosphate) Deep Cycle batteries (with one exception), though different power options are abundant. 

Top Pick - SOK 12V 100 Ah LiFePO4 Deep Cycle Battery

With Bluetooth & Built-In heater

SOK has taken great care with its 100 Ah battery, using the highest quality parts, battery cells, and craftsmanship. The result is SOK’s reputation for stellar customer satisfaction. Regarding features, this SOK 100 Ah 12 V deep cycle lithium battery has the best of three worlds: Bluetooth, in-battery heating, and serviceability. Bluetooth connectivity allows you to monitor your battery’s performance remotely and ensure each cell is functioning properly. An internal heating element allows your battery to thrive in sub-freezing conditions, which may be a critical factor for campers and overlanders exploring or living in cold climate regions. Lastly, this battery is fully serviceable, meaning you can unscrew the top and pop in new cells if ever needed — no need to throw out the whole battery if one cell becomes defective. If these features aren’t something you need, you can save money but still enjoy high-quality construction with other batteries on our top 10. For a full review and inspection, see Will Prowse’s video on the SOK 100Ah battery. 

Best Serviceable Battery - BigBattery OWL 12V 170 Ah LiFePO4 

The one exception to our 100Ah review rule is this fully serviceable BigBattery OWL unit, and that’s because it just doesn’t come in a 170Ah option. We had to include it because it’s one of the easiest batteries to disassemble and replace cells if ever the need arises. The BigBattery has the highest price tag on our list at $979, but because it’s 170Ah, the price per watt-hour is just $0.44, putting it well in the middle of the pack.  What this battery doesn’t have going for it is weight: 47 lbs, at least 15 lbs more than the others on our list. For a more in-depth review of this battery, check out this video by LithiumSolar. 

Best Small System Battery - Renogy 12V 100Ah LiFePO4

Yes, part of the reason this Renogy battery made it so high on our list is its current sale price: $549, which we consider an extraordinary deal for the quality construction and materials Renogy has employed here. We call this a small system battery because its so lightweight (just 29 lbs), and because it cannot be connected to other Renogy batteries to increase voltage. What this battery is perfect for is the energy needs of a conversion van, overlanding rig, or offroad trailer as those rarely require more than one house battery to meet energy needs. What’s even more impressive is the bluetooth capability included with this Renogy battery, making energy monitoring an absolute picnic. For a closer look at the performance of this better check out the video made by Trailer Tim’s Smoke and Wires.

Best Budget Battery - Weize 12V 100Ah LiFePO4

Usually, cheap LiFePO4 batteries are just that — cheap. The Weize LiFePO4 100Ah 12V is one of those rare exceptions that seem to defy the odds of cheapness. At just $400 and $0.31 per watt-hour plus a whopping 10-year warranty, the Weize battery should give you the longevity and reliability you need for your setup. A caveat here though. This is a newer battery, not tried and tested for years like a Battleborn or Renogy. Time will tell if this battery performs as well as it advertises. There are no extra bells and whistles on this battery, which is precisely what makes it an excellent budget battery. It will give you the energy you need when you need it without fuss and at an extremely competitive price. For a full breakdown of this Weize battery, check out the Weize review video by Will Prowse. 

Honorable Mention - BattleBorn 12V 100Ah LiFePO4

BattleBorn is one of the most dependable brands on the deep cycle lithium-ion battery market, not only because of their history making batteries and their transparency in production but also due to their hard work in forging an excellent customer/producer relationship. Just a little digging into the BattleBorn brand and you’ll find all the resources and technical information you could ever need to feel confident you’re getting such a high-quality product. The only reason BattleBorn did not make our best battery title is its price. More expensive than most, Battleborn is a hefty investment, but completely worth every dollar for almost all who choose to purchase it.

Honorable Mention: AO Lithium 12V 100Ah LiFePO4

AO Lithium has been in the lithium battery-making business for 15 years, perfecting its craft and building its expertise all the while. Their deep cycle LiFePO4 batteries reflect that depth of knowledge and experience, resulting in a high-quality, dependable deep cycle battery at a competitive price point. Have any doubt about AO Lithium batteries, just browse any of the numerous YouTube reviews of this product and you’ll see why people rate AO Lithium highly. Looking at their 12V 100Ah model, the only thing we did not love about this battery is that it can only do a max of 24V series connection — keep that in mind if you’re looking to build a battery bank. The other room for improvement could be in the warranty. We’d like to see 10 years instead of a 5-year limited warranty it currently carries.

Honorable Mention: Antigravity 12V 100Ah LiFePO4

Traditionally a motorsports battery company, Antigravity has branched out recently into the deep cycle battery market, responding to increased demand for off-grid sustainability among outdoor and motorsport enthusiasts. Antigravity offers two versions of their 12V 100Ah batteries: one with more technological bells and whistles like sophisticated battery monitoring features, and one that’s a bit more “budget friendly” (their words). The one featured here is the budget-friendly version. One of our favorite features of this battery — its 10 year warranty.

Honorable Mention: SOK 12V 100Ah LiFePO4

This SOK battery has all of the most important features of the first SOK we highlighted above but without the extra bells and whistles. It’s easily serviceable meaning you can open it up and replace individual cells. In general, serviceable batteries are a smart choice because manufacturers have no way to cut corners when the consumer can open it right up and find out what’s going on inside. There is no internal heater or bluetooth connectivity in this SOK battery model, which means it can be offered at a more competitive price.

Honorable Mention: Lion Energy 12V 100Ah LiFePO4

Lion Energy produces renewable energy solutions of all kinds including batteries, solar panels, solar generators, and power banks. They also offer off-grid power kits with everything you need to be completely energy efficient with your auxiliary power solution. Their deep cycle LiFePO4 batteries are completely serviceable, come with a seven year warranty, are lightweight, and can be connected in a series for higher power needs.