The Reality Of RV Lithium Batteries
Talking about batteries with fellow RVers will no doubt bring up at least a mention of RV lithium batteries. Many people have heard of them. They are supposedly the latest and greatest in RV battery power. Advertisements for these batteries often lead RVers to look them up only to find the price tag hard to swallow.
What’s the deal with RV lithium batteries? Are they really more expensive? Are they better than lead-acid batteries? Let’s break down the pros and cons of RV lithium batteries to see if they are worth considering, or if they are just a shiny new RV tech fad that can be passed up.
How do RV lithium batteries work?
Batteries, at their basic level, are simple devices. They contain two types of metals submerged in an electrolyte solution. A separator keeps the metals from touching, but ions and the electrolyte solution can still flow freely. Connecting the two plates together with a wire causes a chemical reaction in the battery, which makes electrons flow from one plate to the other.
Think of it as the volcano science experiment that children do with vinegar and baking soda. When you add the vinegar to the baking soda, a chemical reaction happens, causing bubbles. The baking soda and vinegar mixture forms and releases carbon dioxide gas to make the bubbles. In the case of the battery, electrons “bubble out” through the wire in a chemical reaction when the right conditions are present.
In the baking soda experiment, bubbles will stop forming after some time, and you will be left with a different chemical than the original two. The same holds true in a battery. As the chemicals combine and react, they create a new chemical. Eventually, there is no more reaction left to cause the electrons to flow. Your battery volcano effectively stops bubbling.
RV lithium batteries vs lead-acid batteries
The lead-acid battery has been the battery of choice for cars and RVs for many years, and for most RVers, it still is preferred. It relies on inexpensive components, and therefore, it is a relatively cheap battery. They have shown to be reliable, safe, and effective when used properly.
The lead-acid battery contains plates, one covered in lead dioxide and the other made from sponge lead. They are saturated or submerged in a solution of water and sulfuric acid. A separator is used to allow the electrolyte and ions to flow through it without the two metals touching in the battery. When the chemical reaction no longer produces enough power, the process can be reversed by adding electrical current, which changes the chemicals back to their original state. That makes them an effective power supply and storage device.
If you are interested in the way a lead-acid battery works, the video below shows a more thorough explanation as to how lead-acid batteries are built and how they work.
Types of lead-acid batteries
There are two types of lead-acid batteries typically used in RVs. Starter batteries deliver a large burst of power quickly. Deep cycle batteries give off a lower amount of power over a longer amount of time. Deep cycle batteries have thicker plates in their cells. They can stand being discharged to a lower percentage and recharged more often than starter batteries without damage. That is why deep cycle batteries are most commonly found in RVs.
Lithium batteries work on the same principle as lead-acid batteries, but the metals are different. There are many different types of lithium-based batteries used for different applications. The type you are most likely to find used in RV lithium batteries is Lithium Iron Phosphate which is written as LiFePO4.
In all lithium-based batteries, the cathode or positive side of the battery is made of some kind of lithium-based metal oxide, and the negative side or anode is typically made of graphite. There is a separator between them preventing the metals from touching, and an organic compound is used as the electrolyte.
For a more in-depth look at the inner workings of lithium-ion batteries, the video below explains how Tesla makes its batteries that power cars.
Faster, more efficient charging
RV lithium batteries have several advantages over lead-acid batteries, one of which is their fast charging rate. Lithium batteries can be charged much faster than lead-acid batteries.
This is in part because they are more efficient but also because they can be charged at a higher amperage. Amps are kind of a measurement of electrical speed. Basically, the electricity can be pushed into the battery faster, resulting in a faster charge.
You may want to check out our article How To Run Your RV On 30 Amps if you would like a more detailed explanation on volts, amps, and watts.
A faster charge rate makes RV lithium batteries a very attractive investment for those who like to dry camp. They tend to work better for solar, and faster charge times may result in less generator runtime to charge your batteries. So if you like to camp off the grid, they are definitely the Cadillac of batteries for that application.
Another feature that makes RV lithium batteries a great choice for boondocking is their consistent discharge. As a lead-acid battery is used, its voltage drops proportionally to its discharge state. In other words, lead-acid batteries should really only be used up to 50%. After you have used up 50% of the battery, the voltage drops too much to be usable.
Conversely, an RV lithium battery can maintain it’s usable voltage all the way down to an 80% discharge. The result is a more efficient and longer-lasting battery. The graph below is an illustration of lead-acid and lithium discharge curves.
RV lithium batteries are lighter
The energy density of lithium batteries is much higher than that of lead-acid batteries. This means more energy can be stored in a smaller space. It also means an RV lithium battery is much lighter than a lead-acid battery of an equal power rating. Consider the materials used to construct a lithium battery are lighter by nature.
The myths and downsides of RV lithium batteries
They are more dangerous
Lithium is a reactive metal. It’s so reactive it will react with water. What that means is if the electrolyte ever dried up somehow and the two metals inside came in contact, the battery could explode or at the least catch fire.
That drawback kept lithium batteries from coming to the major consumer market for some time. It is also a worry you will find discussed in many RV forums. Many have heard of manufacturing defects in laptop and cellphone batteries melting or catching fire next to a person’s face.
To put this in perspective, millions of lithium-based batteries are manufactured each year, and very few malfunctions happen. You are more likely to wreck an RV on the road than have your cell phone spontaneously combust. RV lithium batteries come with a battery management system or BMS built into them that regulates charging, discharging, and other factors to prevent damage.
Another factor to consider when thinking about the safety of lithium batteries is their makeup. There is a reason that most RV lithium batteries are of the LiFePO4 type. According to RELiON’s FAQ page,
“Phosphate-based batteries offer superior chemical and mechanical structure that does not overheat to unsafe levels. Thus, providing an increase in safety over lithium-ion batteries made with other cathode materials…Lithium phosphate cells are incombustible, which is an important feature in the event of mishandling during charging or discharging. They can also withstand harsh conditions, be it freezing cold, scorching heat, or rough terrain.
When subjected to hazardous events, such as collision or short-circuiting, they won’t explode or catch fire, significantly reducing any chance of harm. If you’re selecting a lithium battery and anticipate use in hazardous or unstable environments, LiFePO4 is likely your best choice. It’s also worth mentioning, LiFePO4 batteries are non-toxic, non-contaminating, and contain no rare earth metals, making them an environmentally conscious choice.”
They don’t work in cold temperatures
Lead-acid batteries have an advantage when it comes to cold weather. They will charge, and though their performance is reduced, they will work in sub-freezing temperatures. Lithium batteries will discharge in cold weather more efficiently than lead-acid batteries, but charging them in below-freezing temperatures can lead to damage that renders them unusable.
It might seem that cold weather campers are stuck with a lead-acid battery, but some companies are finding ways around the cold flaw of RV lithium batteries. RELiON’s LTS series of batteries use a built-in battery heater. The heat generated by the charging circuit is used to warm up the battery before charging in freezing temperatures. The whole unit is contained within the battery.
Other companies like Battle Born Batteries have a built-in circuit that protects themselves from being charged when the battery reaches a certain temperature. They recommend keeping the battery in a heated area such as a compartment or even in the rig to prevent the battery from reaching cold temperatures.
They are more expensive
If RV lithium batteries are so great, why aren’t they preinstalled in RVs? Cost is the answer. The price of materials keeps lead-acid batteries the go-to for most people. You probably aren’t going to spend more than a couple hundred dollars to put deep-cycle lead-acid batteries in your RV. An RV lithium battery is going to set you back about $1300, most likely. As far as the initial cost goes, the lead-acid battery reigns supreme by a large margin.
This disadvantage starts to look like a myth once you run the numbers on long term costs. A battery’s life is rated in cycles. A lead-acid battery will generally last 400 charge/discharge cycles or less. Some RV lithium batteries are rated to last 5,000 cycles. In other words, a lithium battery can last up to 10 times longer than a lead-acid battery.
Putting that into numbers, a high-end deep-cycle lead-acid battery costs about $180. Multiply that by 10 and you get $1800. In the time it takes to use up one $1300 lithium battery, you could have spent $1800 replacing lead-acid batteries. This is over the years of course. When determining if RV lithium batteries are right for you, it’s important to factor in cost over time and not just the initial cost of the hardware.
Another way to look at the investment is to think of how long the product will work. On average, it’s not unusual for a lead-acid deep cycle battery to last up to 5 years when properly maintained.
If an RV lithium battery lasts 10 times longer, you are only going to have to make that purchase once. Now that is all dependent on several factors, so lifetime may vary. It isn’t unusual for lithium battery manufacturers to claim that a 30-year lifespan is possible. That’s a pretty good bang for your buck.
Are RV lithium batteries worth the cost?
RV lithium batteries are lighter, hold more power, can be discharged deeper, and last longer. Though they have problems in freezing temperatures, many companies are making products that address that issue. Thanks to the current materials used in RV applications and technology, they are safe as well. The only real drawback is their price, but they may be cheaper than lead-acid batteries if you factor in lifespan.
There isn’t anything wrong with lead-acid batteries. If you only use your RV a few weeks out of the year, a good quality deep-cycle battery will probably do just fine.
However, if you live in your RV full-time, dry camp a lot, or are thinking about upgrading to a solar system, then they are worth looking into. Read more about Battle Born RV lithium batteries in this previous RV LIFE article.