If you’ve been boating or fishing for any length of time, you’ve probably heard about the different kinds of marine batteries out there.
You may have heard that AGM and gel batteries are some of the best types of marine batteries you can buy.
But what are AGM and gel batteries? Are they the same type of battery, or are they two different types?
If they are different, what are the differences between them? How can you tell which type of battery you have? And, if you need to buy a new battery, which one is the best choice for your boat?
This article will answer all of these questions. Ready to dive in?
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Are Marine Batteries AGM or Gel?
The short answer is, they can be both.
AGM and gel batteries are two related but slightly different battery types. Some marine batteries are AGM batteries, while others are gel batteries.
With that in mind, you may still be wondering: what, exactly, is an AGM battery? How about a gel battery?
Keep reading to find out more.
What Are AGM Batteries?
AGM stands for Absorbent Glass Mat.
Essentially, AGM batteries are a type of lead-acid battery; instead of keeping the battery electrolyte in chambers that have to be refilled, as with flooded lead-acid batteries, AGM batteries hold the electrolyte in a woven fiberglass mat.
This mat holds all the electrolyte the battery will ever need, so you never have to think about adding water to the battery. The electrolyte is used up much more slowly, so AGM batteries generally last much longer than the standard flooded lead-acid battery.
AGM batteries are a popular choice for marine applications because they are less prone to damaging and spilling, don’t produce harmful fumes, and can be mounted in any position.
What’s more, they are relatively inexpensive compared to some of the other flooded battery alternatives. AGM technology has been around for decades, so it’s a tried and true battery design that many people both in and out of the boating industry depend on.
What Are Gel Batteries?
Gel batteries are another type of sealed lead-acid battery. They are similar to flooded batteries except that the electrolyte in the chambers is in the form of a gel rather than a liquid.
There are several benefits of using this gel. For one thing, it doesn’t leak or spill, so you can mount the battery in any position and don’t have to worry about the shocks and vibrations produced by your boat.
Gel batteries, like AGM batteries, are considered maintenance-free because you don’t ever have to add water to them. All the electrolyte the battery will ever need is held in the gel, and once this is used up, it’s time for a new battery.
That said, gel batteries last much longer than flooded batteries because the gel lasts much longer than liquid battery acid.
On top of all these benefits, gel batteries are designed to handle a range of temperature extremes, so they’re a good choice whether you’re ice fishing or enjoying a day on the lake under the hot summer sun.
Are AGM Batteries Considered Gel?
AGM and gel batteries are sometimes confused, but they are not technically the same type of battery.
The confusion comes because both AGM and gel batteries are maintenance-free sealed lead-acid batteries. They are both sometimes called valve-regulated lead-acid batteries (VRLA), sealed lead-acid batteries (SLA) or simply AGM batteries.
Again though, these batteries are not the same. AGM batteries hold a small amount of electrolyte in an absorbent fiberglass mat, while gel batteries hold the electrolyte in gel form.
AGM technology has been around longer than gel technology, and AGM batteries tend to be less expensive than gel batteries.
While both are excellent choices for marine applications, most boaters go for the AGM batteries because they are cheaper and have been around longer than gel batteries.
Still, those who choose gel batteries are rewarded with superior performance no matter how they are mounted or what the temperature is, and a well-made gel battery will most likely last longer than an AGM battery.
How Can I Tell If My Marine Battery is AGM or Gel?
If you’re not sure what type of marine battery you have, there are several ways to find out.
First, check the label on the battery. In addition to the battery’s brand name and some basic information about it, the label should tell you what kind of battery you have. Look for terms such as sealed lead-acid, VRLA, and of course, AGM, absorbent glass mat, or gel.
If you can’t find the type of battery on the label, or if the label is too messed up to read, try looking for your owner’s manual. If you kept the manual after buying the battery, you should be able to find the information you’re looking for in there.
If you didn’t keep the manual, or you can’t find it, you may be able to look up the battery online. First, you’ll have to locate the model or serial number on the battery.
This number may be printed on the label, but you should be able to find it on the battery itself as well. It will most likely be a combination of letters and numbers. Once you locate the model or serial number, type it into your favorite search engine and see what comes up.
Finally, if you can’t locate the model number or you can’t find out any information online, you could always take the battery into a battery or mechanic shop. The mechanic or technician should be able to tell you what type of battery it is and will be happy to help.
Many marine batteries are classified as either AGM or gel batteries. While these two battery types are similar, they are not exactly the same.
AGM batteries store the battery acid in a fiberglass mat, while gel batteries store it in the form of a gel. Both of these battery types are considered maintenance-free sealed lead-acid, or VLRA, batteries, and both are excellent choices for marine applications.
Sarah Hood has been writing for Anchor Travel since 2021. When she’s not writing, she enjoys cooking, singing, and spending time in the great outdoors.