The Differences Between AGM and Flooded Batteries

Posted by Crown Battery on Oct 11, 2017 6:49:00 PM

Rechargeable batteries are manufactured with different technologies. And the most reliable technology for rechargeable batteries is lead acid batteries. With the two most popular forms of lead batteries being Absorbed Glass Mat (AGM) and Flooded or Wet Batteries, what exactly are key differences and how do you know which one is right for you? Here’s what you need to know about each type as you evaluate your battery needs:


Both AGM and flooded batteries are designed for energy storage. Both flooded and AGM rechargeable batteries are within the lead acid category because their design allows currents to be removed and when they meet a reverse current, charging begins.


AGM Batteries:

Because of their glass separator construction, an AGM battery absorbs and retains the electrolyte leaving no free electrolyte in the cell to spill.  These batteries are also more impact-resistant due to their reinforced exterior construction.  The internal resistance of AGM batteries is very low which helps increase voltage, lower the charging times, and reduce the heat as power flows.

The AGM battery is known as the most maintenance-free option in lead acid batteries because they recombine the internal gases back into liquid.  If you need a battery that provides fluid leak protection, minimal corrosion, and no excess parts, an AGM battery is the superior choice.  However, keep in mind that over/under charging impacts the life and performance of AGM batteries. They are also a higher-priced battery option due to the increased cost of components, increased manufacturing costs, and lack of maintenance they require.


Commonly known as “wet cell” batteries, these are the most common rechargeable batteries on the market today.  They come in a variety of shapes and sizes because of their use in so many industries, devices, and equipment.  But unlike AGM batteries, these are not sealed internally, therefore gases release into the air and the environment.  Additionally, to achieve optimum performance, these batteries require careful measurement of internal liquids. 

You commonly see wet cell batteries in areas like backup power sources, off grid energy sources, and utility equipment.  They are also more susceptible to Flooded batteries require periodic preventative maintenance to ensure optimal life and performance.  Many suppliers of Flooded batteries offer best practice recommendations for performing this work – so check with your supplier for more information, or visit for more information.


With AGM and flooded batteries, it’s important to follow the manufacturer instructions for charging and maintenance to secure optimum performance.  If you are careful about connection processes, charging, and a safe storing environment, you are taking necessary steps to protect your battery investment.

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Tags: Lead Acid Batteries