AGM vs Deep Cycle Flooded Batteries

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Batteries are a genius invention in the world of energy storage. Not only can they provide flexible power, but they also respond the fastest of all other forms of energy storage. And like any other invention, different types of batteries work differently. The most common ones are acid batteries, with the two main ones being AGM and flooded batteries. When you think of buying a battery, there are a lot of factors to consider. Today, we will help you decide between AGM vs deep cycle batteries. In this piece, you will learn the pros and cons of using each type and which is best.

AGM vs Deep Cycle Batteries

What Is a Deep Cycle Battery?

A deep-cycle battery is designed to provide sustained power over an extended period of time, often until it is about 80% discharged. It is powered by lead. However, while these batteries can discharge up to 80%, manufacturers recommend that you do not let them discharge below 45% to boost longevity.

An excellent deep cycle battery is versatile, allowing you to use it in marine applications, recreational vehicles, golf carts, and off-grid renewable energy.

Types of Deep Cycle Batteries

There are two main types of deep cycle batteries: sealed and flooded. Each option has distinct features and benefits. Here are a few insights into each of them.

Sealed Batteries

You can also refer to it as a maintenance-free or a valve-regulated lead acid battery. These batteries are sealed against spilling or electrolyte loss, meaning they do not require water refills. This option is further categorized into AGM and Gel.

Flooded Batteries

Flooded batteries are also referred to as wet cell batteries. Typically, this option uses a liquid electrolyte that helps trigger a chemical reaction to charge. They are common and have been on the market for the longest time. If you are looking for an affordable alternative, this choice will be worth it.

Deep Cycle AGM Batteries

The Absorbent Glass Mat (AGM) is a class of lead-acid batteries whereby the electrolyte is absorbed into the fiberglass mat. The plates may be flat like wet cells or wound up in a tight spiral. The fiberglass inside the battery acts like a sponge that holds the electrolyte in place. It makes it less likely that acid will leak or spill, thus avoiding frequent top-ups.

Features of AGM Batteries

  • Low internal resistance.
  • The AGM battery charges faster than a gel or flooded battery.
  • Offers an 80% Depth of Discharge (DoD).
  • Excellent recovery performance.
  • Low-temperature startup capabilities.
  • Leak-proof, and low-maintenance.

Pros

  • They are maintenance-free, as they have a sealed electrolyte; thus, no need for watering.
  • They are robust, lighter, and more durable.
  • AGM batteries are vibrational and shock-resistant since the lead plates act as dampers.
  • They have a high power output.
  • Very slow self-discharge rate.
  • Excellent charge retention capabilities.
  • High performance, including in extreme temperatures.
  • Have a long life span compared to conventional batteries.

Cons

  • It can be significantly expensive, particularly when compared to flooded batteries.
  • Lower tolerance to overcharging.

Applications

You can use AGM batteries in different setups. The following are some of the top applications for AGM deep cycle batteries.

  • Used as off-grid power systems, including renewable systems, i.e., wind and solar power.
  • Cyclic operations, i.e., mowers, cleaning machines, wheelchairs, and golf carts.
  • Marine applications.
  • Used in electric vehicle services.
  • Used in uninterrupted power supply systems, i.e., robotics and medical systems.
  • Motorcycles and all-terrain vehicles.
  • Recreational vehicles etc.

Deep Cycle Flooded Batteries

Deep cycle flooded batteries are an excellent alternative to AGM batteries. It is the standard lead acid battery, often used in vehicles. Its lead plates are thicker when compared to standard flooded batteries. They are submerged in a blend of water and sulfuric acid. Usually, this battery produces gases from the chemical reaction that occurs during charging. In addition, it is made from a thick antimony lead alloy, guaranteeing robustness.

Here is a breakdown of the features and advantages you can expect from this battery.

Features of Deep Cycle Flooded Batteries

  • Has thicker plates than standard flooded batteries.
  • It dispenses gas from the chemical reaction during the charging process.
  • Its usable capacity is between 30 and 50%.
  • Is often charged in steps that leave room for overcharging or undercharging.
  • It has a charging efficiency of between 70 and 85%.
  • Its design makes it easy to check the electrolyte levels and add more when needed.

Pros

  • Its initial cost is relatively low.
  • Can be produced for a multitude of uses.
  • Large current capability.
  • Tolerance for overcharging.
  • Easily used as backup power.
  • Availability in a wide range of sizes and specifications.

Cons

  • It requires constant maintenance since it contains a free liquid.
  • Corrosive electrolyte.
  • Not suitable for fast charging.

Common Uses

You can use flooded batteries in different settings, thanks to their reliability. These batteries are commonly used in cars, boats, RVs, standalone electrical systems, and stationary uninterrupted power supplies. Typically, they offer a steady supply of energy, guaranteeing reliability.

AGM vs Deep Cycle Flooded Batteries: Which Is Best?

AGM batteries are sealed in nature, while flooded batteries are not, making the AGM battery suitable for lower mechanical requirements. It is an excellent choice when looking for exceptional performance and reliability. Besides working well in extreme temperatures, this battery has a slow discharge rate, making it ideal for long-term use. 

The flooded types are less expensive compared to the AGM batteries. If budget is not an issue, AGM batteries will be a better choice than deep cycle flooded batteries.

FAQs

AGM vs Deep Cycle Batteries - FAQ

Is an AGM Better Than a Flooded Battery?

There is no one-dimensional answer to this, as the choice depends on the application. An AGM battery is excellent for recovery and performance in extreme temperatures. However, a flooded battery will be a practical choice if you are on a budget.

Can I Use Flooded Battery Instead of AGM?

The use depends on the applications in question, i.e., for deep cycling applications, one can freely swap between the flooded and the AGM batteries. Nonetheless, it is not advisable to use a flooded battery in tight areas that can’t ventilate well.

Does AGM Charge Faster Than Flooded?

Yes. AGM batteries charge up to five times faster than flooded batteries.

What Is the Main Disadvantage of AGM Batteries?

Cost. AGM batteries have a relatively high initial cost, deterring most people from getting them.

What Is the Significant Difference Between AGM and Gel Batteries?

The difference is in their construction. An AGM battery has its electrolytes enveloped in a glass mat internally. On the other hand, a gel battery uses a gel paste as electrolyte.

Final Thoughts: AGM vs Deep Cycle Batteries

AGM and flooded deep cycle batteries are lead batteries and contain electrolyte solutions that cause a chemical reaction to produce electrons. The batteries differ because they both have cons and pros, as discussed above; thus, taking into consideration these differences is necessary when using either battery.
As you look forward to choosing the perfect battery for your machine, ensure that you compare these options and select whichever suits you best.
James Owen

James is an engineer and a professional blogger. He has gained extensive experience over the years, handling all types of power projects. He loves to share his experiences with all things related to batteries, generators, and other power-related topics.

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