How Do I Know If My Battery is AGM or Standard?

We often hear this question from first-time RV owners: “How do I know if my battery is AGM or standard?”

The surest way to know if you have an AGM battery is to read the label.

Most AGM batteries have the term spelled out on a plate or sticker. But what if you cannot read the label? Keep reading to learn how.

Battery Classification Guide

Let’s start the standard vs AGM battery differentiation by learning more about battery classification.

1. Batteries According to Function

Starter Batteries

These batteries feature thinner plates to ensure the least possible internal resistance, allowing more electricity to flow. This battery is perfect for starting an automobile engine, including an RV.

House Batteries

Also known as deep-cycle batteries, house batteries feature thick plates, allowing them to deliver electricity at a constant rate.

While a starter battery delivers high-energy bursts, deep-cycle batteries emphasize capacity. It enables you to power machines and appliances longer.

2. Batteries According to Construction

Flooded Lead-acid (FLA) Batteries

These batteries have been around since the mid-19^th century, and they discharge about 15% of their capacity every month.

Also called “wet batteries,” FLAs have cell openings that can become the source of leaks or spills. They also require periodic maintenance (i.e., refilling the electrolyte solution).

The good news is their depth of discharge often reaches 80%.

Sealed Lead-acid (SLA) Batteries

As the name implies, SLAs don’t have cell openings, creating a spill-free or leak-proof battery. These batteries have a 3% monthly discharge rate and a maintenance-free design.

We can categorize SLAs into “absorbed glass mat” (AGM) and gel. Although these batteries might look similar, they vary in their electrolyte integration.

Gel SLAs use a gel-like substance to suspend the lead acid in the battery. Meanwhile, AGM meshes the lead acid into glass mat fibers, preventing it from spilling.

These attributes give SLAs other names, including “maintenance-free,” “sealed maintenance-free,” and “valve-regulated lead acid” batteries.

So, you can be 50% sure you have an AGM battery if you have these terms on the battery label.

How to Tell if the Battery is AGM?

1. Read the Label

The most straightforward way to identify battery type (any type) is to read the information on the label. This trick only works if the print is still readable.

Some batteries might not have “AGM” on the label, but “absorbed glass mat.” It’s the same thing, only spelled out. Some manufacturers might use other terms, such as “dry cell,” “sealed regulated valve,” valve regulated,” and “non-spillable.”

These words describe an AGM battery’s characteristics and can strengthen your assumption that the unit is AGM.

If you cannot see these “terms” on the battery label, you can look for the battery’s model number. Use this information to search for its battery type in an online resource.

2. Look at the Battery’s Top.

Suppose battery label identification is impossible due to unreadable information or a peeled-off label. In that case, you can focus on the battery’s top.

AGM batteries don’t have caps or removable panels on the top section. Instead, the only protrusions you’ll see are the two battery posts (negative and positive). The surface should be plain except for the terminals.

3. Determine if There is Liquid in the Battery

Consider this trick a confirmatory method. One crucial attribute in the AGM vs standard battery debate is electrolyte liquid. Although AGMs contain electrolytes, most of it is in the fiberglass mat fibers.

Hence, shaking the battery will give you an idea if it’s AGM or not. You know you have a standard battery if you can sense liquids swirling or swishing inside the battery casing once you shake it. If not, you’ve got an AGM battery.

Conclusion

How do I know if my battery is agm or standard? Well, differentiating an AGM battery from a standard type is easy. Just look for specific terms on the battery label signifying it’s AGM and not something else. If unsure, you can also look for battery physical characteristics that say “AGM” and not another battery type.

Ascertaining the correct battery type will help you maximize its capacity and observe measures to prolong its lifespan. It is one of the best ways to ensure a more satisfying RVing experience.