RV Battery Basics

When shopping for deep-cycle batteries for your RV, you’ll see both lead acid RV batteries and lithium RV batteries. What’s the difference between a lithium RV battery vs a lead acid battery? I tell you here!

Lithium RV battery and lead acid battery differences

Both serve the same basic function: to provide power to your RV over a long period of time. Both are designed to be discharged until almost empty then recharged (this is what deep-cycle refers to). However, when comparing a lithium RV battery to a lead acid battery there are plenty of differences. 

First, let’s look at what specifically a lead acid RV battery is and what a lithium RV battery is. Then we’ll compare the differences between them.

What is a lead acid RV battery?

The lead acid RV battery like all lead acid batteries uses flat plates of lead submerged in an electrolyte. This allows it to store a charge and provide power in many applications especially in cars and RVs. 

Lead acid batteries are fairly old technology. Over time, a number of different kinds of deep-cycle RV batteries have been developed.

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Flooded lead acid batteries

The first kind is the flooded lead acid battery. They’re called this because the lead plates are completely covered by a liquid electrolyte. They’re cheap and fairly reliable but they have several downsides:

  • They need to be regularly topped off with distilled water
  • Freezing temperatures destroy them
  • They’re very big and bulky
  • They don’t have a very long lifespan
  • Lead acid batteries can emit toxic gases in a process known as off-gassing
  • They must be stored upright or you risk spilling the electrolytes 

To overcome these limitations, new lead acid battery technologies were created: gel and absorbed glass mat.

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Gel batteries

The first is the gel battery. Instead of a liquid electrolyte, these use a semi-solid gel. These batteries are designed to be used in any orientation. They are completely sealed meaning they don’t experience off-gassing and are resistant to spillage. 

Absorbed glass mat batteries

The next is the absorbed glass mat (AGM) battery. AGM batteries use fiberglass mats to absorb the electrolyte. This arrangement makes them spill-free and gives them other advantages. For example, these batteries can be charged faster, be discharged more deeply (up to 80 percent), and are resistant to off-gassing and freezing temperatures.

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What is a lithium RV battery?

Lithium batteries also called lithium-ion batteries use the metal lithium in place of lead. There several different types. In most cases, your lithium RV battery is going to be a lithium iron phosphate battery. These are usually referred to as LiFePO4 batteries.

LiFePO4 batteries have many benefits over lead acid batteries:

  • They can store more energy in a smaller space because they have a higher energy density than lead acid batteries
  • They have a flat discharge curve which means they provide a consistent current for longer
  • They have very low self-discharge so even if these batteries are stored without use for long periods they’ll still hold a charge.

LiFePO4 RV batteries also have advantages over other kinds of lithium batteries. 

For one, they’re much safer. Some kinds of lithium batteries are unstable and pose a risk of fires and even explosions! LiFePO4 batteries, however, are highly stable and safe and won’t explode or catch fire. 

LiFePO4 batteries don’t require the use of nickel or cobalt. This makes them somewhat cheaper to produce as these materials are very expensive and hard to find. It also avoids the ethical concerns surrounding cobalt mining.

Lastly, a lithium-ion RV battery can be discharged by as much as 100 percent before recharging. They can also be recharged very quickly because you can use very high charge rates. 

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Lithium RV battery vs lead acid RV battery

Now that we’ve covered the nuts and bolts of both lithium and lead acid batteries, we can compare them directly. Let’s look at the big differences between a lithium RV battery vs a lead acid RV battery. 

Performance

In every measure of performance, the lithium ion RV battery comes out on top. A lithium battery provides more (and more consistent) power—and for longer!

At the low end, some flooded lead acid batteries can only discharge up to 30-50 percent of their capacity. Even for the more advanced AGM battery you’re only looking at 60-80 percent discharge.

By comparison, a lithium RV battery will provide 80 percent (to as much as 100 percent) of its capacity before you need to recharge it. Plus it can recharge more quickly than a similar lead acid RV battery.

Lifespan

When it comes to the lifespan of a lithium RV battery vs a lead acid battery, lithium wins again.

A battery’s lifespan is measured in cycles—a.k.a. the number of times it can be discharged and recharged. For a lead acid RV battery, the lifespan is usually in the hundreds range. Some will have as few as 300 cycles whereas only some batteries survive over 1,000 cycles. 

A lithium RV battery, meanwhile, delivers thousands of cycles over its lifespan. Some batteries can provide as many as 5,000 cycles!

To put the number of cycles in a battery’s lifecycle into a time perspective: a lead acid RV battery will last 2 to 5 years; a lithium RV battery can last 10 years or more.

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Cost

This is one of the few cases where a lead acid RV battery might come out on top in the debate of lithium RV battery vs lead acid. 

A lead acid RV battery will generally cost between $200 and $700 (depending on the size and type). The cost of lithium RV batteries starts at around $900 and can go up to multiple thousands of dollars. So for your initial investment, you’re spending as much as 5 times more for a lithium RV battery vs a lead acid.

However, while a lead acid RV battery may be cheaper upfront, that doesn’t tell the whole story. Remember that a lead acid battery only lasts a few years while lithium batteries can last a decade or more. Over the same time span, you’ll likely spend the same amount (or even more!) replacing your lead acid batteries every few years. 

To boil it down, a lead acid RV battery may save you some money in the short term. But, in the long run, a lithium RV battery could ultimately save you money.

Weight

The last category for comparing the lithium RV battery vs lead acid is weight. And once again, the lithium RV battery is our winner. 

Because of their higher energy density, lithium batteries are much, much lighter than lead acid. In fact, lithium RV batteries are half the weight of lead acid batteries or even lighter!

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Conclusion

Lead acid batteries have some perks because they’re such old technology. They’re cheaper upfront and while they may require some maintenance, they’re highly reliable. But when you compare a lithium RV battery vs lead acid, lithium is almost always better.

A lithium battery will be lighter, more efficient, and more powerful than lead acid. And while they cost more they also last much much longer so they save you money over time. Because of all these factors, lithium RV batteries are the best choice for most RVers.

Worth Pondering…

Anyone who stops learning is old, whether at twenty or eighty. Anyone who keeps learning stays young. The greatest thing in life is to keep your mind young.

—Henry Ford