Battery Basics – Types of RV Batteries

Learn about the different types of RV batteries, how to care for them, and what might be the best RV battery for you. We’ll go into the most common types of batteries but try to keep it easy to understand.

Battery Basics – A Series to Learn About Batteries

Battery Basics – Types of RV Batteries
Battery Basics – How to Care for RV Batteries
Battery Basics – True Deep Cycle vs Dual Purpose
Battery Basics – How to Wire RV Batteries
Battery Basics – RV Battery Sizing

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Choose the Right Battery for Your RV

Don’t get sold cheaper batteries, learn the differences here.

Batteries are the heart of an RV’s electrical system. They contribute to comfort and safety. When dry-camping, camping without power or water hook-ups, the battery keeps your RV alive. The battery powers lights, fans, water pump, smoke detector. Many consider batteries voodoo and leave their comfort and safety to the trust of others. Those ‘others’ might not know much more than you do. Use the Battery Basics series to learn what you need.

The core of an RV’s electrical system is its batteries. They add to your comfort and safety by giving you the power to explore wherever you want. The battery keeps your RV running whether you’re dry camping or boondocking (camping without electricity or water hookups). Lights, fans, a water pump, and a smoke detector are all powered by the battery. Many people see batteries as voodoo and entrust their comfort and safety to the trust of others. Those “others” may not know much more than you. Learn more by reading our Battery Basics series.

Types of RV Batteries for Your RV

There are two main chemistries when it comes to commercially sold RV batteries. It’s important to familiarize yourself with the different types of batteries so you can make the best choice for your RV experience. For instance, WET-type batteries require filling of distilled water – which might not be the best for dry desert areas. Lead-Acid is MUCH heavier than lithium, about 65% heavier.

Common Types of Commercial Sold RV Batteries:

1. Lead-Acid – Types or names include WET (flooded and sealed), GEL, AGM
2. Lithium – Types include Lithium Iron Phosphate (LiFeP04 the safest lithium tech), Lithium-Ion (various chemistries)

Let’s dive into different types of batteries that are available for your RV and give you some information so you can make the best choice when it comes to RV batteries.

WET Cell Battery, AKA Flooded, VSLA, & SLA

WET, WET CELL, VSLA, and SLA are all WET types of lead-acid batteries you’ll commonly see sold for RVs, off-grid, and renewable power applications. You can definitely hear sloshing around in these batteries when you carry them. They are called WET or FLOODED as they contain a solution of water and sulfuric acid. This acid solution chemically reacts with big lead plates to create electrical power.

WET-type lead-acid batteries are probably the most common RV battery. They are the cheapest type of RV battery that packs a punch you can buy. Most RVers replace their batteries every 1 to 3-years, but this is only because they don’t know how to maintain or use them correctly. I hope this battery basics series helps you choose and care for your batteries better. If you need help with battery questions please reach out – info@backcountrysolar.com

WET batteries require the most attention. They require regular maintenance to make sure they don’t dry out and get damaged. The acid solution level is important to the health and longevity of WET batteries. You can maintain the batteries by making sure they stay filled up with distilled water. Distilled water must be used n WET batteries as non-distilled water carries minerals that can contribute to the corrosion inside the battery.

Many People Don’t Know How to Maintain WET Lead-Acid Batteries – Here’s What to do

I guess I shouldn’t be very surprised. RV manufacturers and RV dealers don’t do a great job at explaining how to care for batteries. They just want you to buy and be on your way. Maybe I’ll start a series about RVs and RV dealers in the future!

When a battery is discharged or charged (you use the battery or charge it up) it generates heat. In a WET battery that has caps to refill the water, this heat causes the water to evaporate. This is why you have to keep filling them. When you live in a dry climate the amount of evaporation can increase. Both the use of your battery and the climate needs to be considered when deciding how to care for WET batteries.

When to Check Water Levels in WET Batteries

We recommend checking your WET battery water levels monthly if you’ve never done it before. Within the first year, you’ll be able to understand how your usage and the climates you camp in effect the water levels. Adjust checking the water levels based on your first-year experience. It’s not uncommon to only check water levels every 3 to 6-months. We also recommend checking your WET battery water levels when you get your RV out of storage and when you put it back.

If you have a large battery bank there are full systems you can install on your RV that will make caring for your batteries super easy. Here are some other types that can make it easy.

Get a Hydrometer for WET Batteries

We’re going to have a link to an article here that links to how to take care of your batteries (coming soon). We’ll also have an article on how to use a hydrometer to check your battery.

Absorbed Glass Mat, or AGM Type Lead-Acid Battery

AGM batteries are a type of lead-acid battery. AGM stands for Absorbed Glass Mat. They still have the lead plates and the acid-water solution but the solution is soaked into a fiber type mat inside the battery. The fiber mat helps to suspend the fluid around the lead plates. This suspension of fluid can help even out the chemical reaction leading to better performance, and longer life.

AGM batteries are also sometimes referred to as “dry” lead-acid batteries, in comparison to a WET-type lead-acid battery. AGM batteries can be marketed as “Maintenance Free” or “Non-Spillable”. AGM batteries don’t require you to fill them with water. The battery is sealed and generally the water they start with remains in the battery for its life. The only real service you might need to do to these batteries is to clean their terminals from time to time and keep it properly charged. AGMs don’t have any holes that require watering. But they do have a pressure release valve if there is a malfunction.

AGM type lead-acid batteries are well known to be a better pick for an RV. There isn’t a need to constantly check the fluid levels which makes ownership a little easier. The fiber mat inside the battery also helps even out the chemical reaction. By doing this AGM batteries generally have a better performance compared to other deep cycle batteries. The downside is that they can cost up to twice as much as WET-type batteries.

PROs and CONs of AGM Lead-Acid Batteries

GEL Type Lead-Acid Battery

GEL is yet another sealed lead-acid battery. This type of battery isn’t very common in RVs anymore. They had their time in the light when they were new. There were also several manufacturers that created poor quality GEL batteries and gave the chemistry a bad rap.

GEL batteries are made with a paste-type solution, as opposed to a water-acid or fiber mat. GEL batteries have a similar performance to AGM batteries, with strong charging and discharging. But GEL has a little better performance with deep discharges, better than any deep cycle lead-Acid battery. However, they are very sensitive to overcharging and require a much lower charge voltage. Since many RVs come with simple chargers, many of them a single stage trickle charger, they can easily overcharge a GEL battery and shorten its life. It’s best to use a specific GELL battery charger for GEL batteries to prevent any overcharging.

GELL batteries are also fairly expensive. If you do get a GEL deep cycle battery we recommend not to skimp on the brand and go with something that has proven performance.

Lithium Type Deep Cycle RV Batteries

Lithium batteries pack a punch. Can be discharged fast and charged up faster than any other type of deep cycle battery. They are lighter, about 60% lighter than other lead-acid batteries. Can be mounted in any position. And don’t require any real maintenance. A win all the way around (almost, not so great in cold temps).

Lithium battery technology has been around since the ’70s and ’80s, much longer than you think. But the cost of the components of the battery has prohibited mass acceptance into the RV market up until recently. Lithium battery technology is advancing fast and the market is maturing. We’re increasingly seeing viable and valuable options for RVs.

However, it’s worth noting that not all Lithium-Battery types are the same. There are safer lithium batteries designs, and we recommend sticking to the safest option for your RV – Lithium Iron Phospate or LiFeP04.

Lithium Technology Can Vary – Choose The Safer Option For Your RV

You might remember when a Samsung phone caught fire on a plane. The fire was caused by the lithium battery, but that battery was a lithium-ion type battery. Lithium-ion is a general name for a lithium battery and how the battery is built can vary. The Samsung battery had issues with a material that separates the two reactive materials. The degradation caused thermal runaway and an explosive reaction. It’s scary, but the battery was small enough that no one was injured.

The safer option is getting a Lithium Iron Phosphate type battery for your RV. They are one of the oldest chemistries for lithium-type batteries and have proved to be a very safe option. Most lithium batteries for your RV will be a lithium iron phosphate chemistry, but if it’s doesn’t explicitly say this, it’s worth checking – especially those cheap Chinese batteries.

RV Lithium Batteries Have AMAZING Performance

Lithium batteries have different characteristics compared to Lead-Acid. Lithium batteries are a true DEEP CYCLE battery. They can be drawn down to less than 20% and charged back up with little loss of life. The recharge rate is much faster all the way to full (we’re talking they can charge up to twice as fast). The discharge current or the amount of power you can draw from the battery is exceptional, and that is the same for the charge current.

Charge and Discharge Rates

Most single lead-acid type RV batteries can’t exceed a 25-amp charge current, but single lithium type batteries can easily reach 80-amps. There is a similar characteristic for discharge rates, it’s a bit more in-depth so maybe more at a later time. But, lead-acid can handle a decent discharge current, typically 50 to 80-amps, but lithium can easily hit 80 to 100-amps (single battery).

Charging Time

RV Lithium batteries have a much faster charging time. The main reason for this is that lithium batteries can take a large charge current up to about 95% full, whereas, lead-acid type batteries have to taper the charge current after 80% full. This is particularly good for using renewable energy as a charging source.

At about 80% a lead-acid battery needs to have the charging current reduced so it doesn’t heat up the battery. The last 20% of charging takes a considerable amount of time – generally longer than charging a lead-acid battery from 50% to 80%. After about 80% the charge current is slowly reduced to a trickle charge. This both helps the battery last longer and prevents any excessive pressure build-up in sealed or AGM style batteries.

Battery Lifespan – Lithium is a Clear Winner

Typical lead-acid batteries when used down to 50% and charged back up can last up to 8-years, I’ve even seen well-maintained lead-acid batteries last up to 13-years. Lithium batteries, on the other hand, can easily last up to 10-years, and after that still have 90% of their rated life available.

Even though lithium batteries are much more expensive than comparable lead-acid batteries, the performance and lifespan of the battery make them a clear winner in terms of money invested. You’ll likely need to replace lead-acid types batteries at a rate of 2 to 1 of the lithium-type batteries.

One Main Downside to Lithium Batteries For Your RV

A big downside to Lithium type batteries for RVs is cold-weather performance. It’s not about the power output in cold weather, but if you charge the battery when it’s too cold, it’s ruined. You can’t fix it and the battery needs to be replaced.

There are advancing technologies that are helping prevent lithium cold charging issues, so it’s worth digging into them to see if there is a fit. A few to check out:

• Battleborn Lithium Battery Heated Pad
• Victron Lithium Battery Monitor with Temp Sensor

We plan to write more on this later. It’s a big topic that’s complex. But if you’re in the market for a lithium battery, and you will use it in below 30°F temps, we recommend getting a battery that has low temp protection. The battery itself will prevent any charging until the internal temperature of the battery is safe to charge.

RV Batteries Are a BIG Topic

RV batteries are a big topic. We have years of experience and knowledge when it comes to them. We hope this article helped. We’ll be creating more when we get a chance. If you want to be notified when we have more info, sign up below.

And for this reason, if you’re still confused you can reach out to us. We can do an energy audit for you and calculate what size battery, type, and voltage might work for you. We can also size your solar system. We’ll need to hop on a call and get some info and ask some questions so we can get you rolling with some good recommendations.

For this consultation, we do have a fee of $49.95 per consult. Just reach out to us – info@backcountrysolar.com if interested.

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