When it comes to caravan and camper trailer batteries, two of the most popular types are AGM and Lithium batteries. Both have their advantages and disadvantages, and choosing the right one for your needs can make a big difference in terms of performance, cost, and durability. In this blog article, we’ll take a closer look at AGM and Lithium batteries, compare their features and benefits, and help you decide which one is best for your particular application.

Depth of Discharge (DoD)

If a battery is discharged beyond a certain threshold, it can be negatively affected. The depth of discharge refers to the proportion of the original charge that can be safely depleted without causing damage to the battery.

Lithium Batteries

Modern lithium-ion batteries have a depth of discharge of 98%. So you can discharge almost the entire charge without damaging the unit. This provides optimal conditions for use with most of the stored power available.

AGM Batteries

Like other lead-acid batteries, the depth of discharge is about 80% when new and 50% when older. This makes them less competitive compared to lithium-ion batteries.

Winner: Lithium-ion batteries have the highest depth of discharge and a longer operating time.

Battery Lifespan

Regardless of type, its performance gradually declines with time. Eventually, there comes a stage when the battery will no longer be functional and will need to be replaced.

Lithium Batteries

LFP technology is known for its superior durability, typically degrading by less than 1% per year and providing about a 10,000 charge cycle life.

AGM Batteries

These degrade quickly, providing a useful lifespan of about 500 charge/discharge cycles.

Winner: A lithium-ion battery has a considerably longer lifespan, typically about six times longer than an AGM battery.

Battery Size and Weight

Size is a key concern for people working with limited space, such as owners of caravans.

Lithium Batteries

Lithium-ion batteries weigh less due to the absence of any liquid acid. Additionally, since they have a higher depth of discharge, a smaller lithium-ion battery can provide the same power as a larger lead acid battery.

AGM Batteries

AGM batteries contain absorbed liquid acid that creates added weight. Additionally, a low depth of discharge means that you need a high-capacity (big) battery for any given application.

Winner: Lithium batteries are the better choice in terms of weight and size.

Charge Time and Efficiency

Generally, more efficient batteries tend to have a shorter charging time because of fewer electrical losses. A shorter charge cycle leads to better utilisation of the current used to charge it.

Lithium-Ion Batteries

Due to their higher efficiency, smaller lithium batteries can do the same job as larger AGM batteries. They also charge faster.

AGM Batteries

Although they charge considerably faster than wet lead-acid batteries, AGM batteries still charge much slower when we compare them with lithium-ion batteries.

Winner: Lithium-ion batteries charge faster than AGM batteries and over four times faster than general lead-acid batteries.

Battery Maintenance

Learning about the maintenance requirements of a battery is crucial before buying one. Also, maintenance often leads to added costs and modifications you need to make to your battery setup.

AGM Batteries

Lead-acid batteries are notorious for high maintenance requirements, such as regular electrolyte top-ups. Although AGM is a type of lead-acid battery, it does not require such maintenance steps. This is because it is a completely sealed design.

However, even so, AGM batteries require appropriate venting for the evacuation of gases. Additionally, you need to monitor the charging process, as overcharging can cause permanent damage.

Lithium-ion Batteries

Lithium-ion batteries are a fit-and-forget solution which decreases the maintenance requirements. This is especially true for LFP models.

Winner: Lithium-ion batteries offer a completely maintenance-free experience.

Environment Friendly

As the world becomes increasingly focused on sustainability, environmentally-friendly processes and equipment are created to be less damaging to the environment. 

Lithium-ion Batteries

Lithium-ion batteries are a completely sealed system and do not release any chemicals. Additionally, LFP technology avoids using toxic chemicals such as Cobalt. Instead, it uses more stable elements such as Phosphate.

This is why LFP technology is considered the most environmentally friendly battery option available.

AGM Batteries

While AGM batteries are a greener option than conventional lead acid batteries, they still emit harmful toxic fumes to the environment. Additionally, their constituents are also very damaging.

Winner: Lithium-ion batteries are more environment-friendly than any lead acid battery, including AGM.

Battery Warranty

As purchasing a battery typically involves a considerable financial investment, consumers often seek reassurance through warranty coverage. The availability of extended warranties can be interpreted as the manufacturer’s confidence in the longevity and quality of their products.

Lithium-ion Batteries

Lithium batteries usually come with warranties of three years or more. In fact, Eco Tree Lithium’s LFP batteries come with a written warranty of 6 years.

AGM Batteries

Since an AGM battery has a shorter life than LiFePO4 versions, you obviously get a short warranty with an AGM battery. Generally, you can expect an AGM battery to be covered for about 1-2 years.

Winner: Lithium iron phosphate batteries offer the best warranties, especially if you buy them from a reliable source such as Eco Tree Lithium.

Battery Safety

Neglecting to prioritise battery safety can result in significant harm to both individuals and property.

Lithium-ion Batteries

Lithium-ion batteries produce no build-up of gases, and there are no toxic liquids. You can use them without any additional safety precautions required. Also, Eco Tree Lithium batteries come with added security measures such as a fire-resistant case.

AGM Batteries

Although a sealed battery, like gel batteries, AGM technology still produces a considerable build-up of gases such as Hydrogen. Without proper ventilation, these gases can ignite and cause battery explosions. Additionally, these are also very poisonous gases.

Winner: If safety is your concern and you want an easier-to-handle battery, lithium-ion should be your go-to choice.

Final Thoughts

Although lithium batteries are more expensive, they are often the preferred choice for deep cycle applications due to their enhanced efficiency, compactness, and reduced weight, among other advantages. While they may require a significant initial investment, once you have experienced their superior performance and extended lifespan, you may regret not making the switch earlier.

Frequently Asked Questions

Here are the answers to some commonly asked questions regarding AGM flooded lead acid batteries and lithium-ion battery banks.

1. Is AGM better than a lithium battery?

No, lithium batteries offer a far superior performance than an AGM battery. You would need an AGM battery bank to achieve the same amount of performance as a single lithium battery.

2. What is the main disadvantage of an AGM battery?

The main disadvantages are a shorter lifespan, less capacity, and longer charging times.

3. Can I swap my AGM battery for a lithium battery?

Yes. You can easily swap your AGM battery bank for a lithium battery. Even a lower-capacity lithium battery system can offer the same power as two AGM batteries. The only thing you need to keep in minds is your Battery Management System, Battery charger and solar regulator and whether they are Lithium compatible.