AGM vs Lithium Battery for Boat

AGM vs Lithium Battery for Boat

When it comes to powering our boats, AGM vs lithium battery for boat are often the two batteries that most people consider.

The choice depends on the boat and on your preference. In this article, we would dissect each of these batteries for battery understanding.

AGM vs Lithium Battery for Boat
AGM vs Lithium Battery for Boat

AGM vs lithium battery for boat

The first thing we would consider is their pros and cons.

AGM Batteries

AGM (Absorbed Glass Mat) batteries were initially designed for the military. They used the battery for their UPS, heavy-duty vehicles, and aircraft in the 1980s.

These batteries are more reliable and lighter, and able to withstand most conditions.  You can find the electrolyte next to the plates and hold in thin fiberglass mats.

Pros for AGM Batteries

The batteries are spill proof due to the fact that they are held in fiberglass mats. As a result,  they won’t spill, even when they are broken.

  • You can easily transport them and are exempt from hazardous materials restrictions.
  • The AGM batteries are vibration resistant. Therefore, they can withstand constant vibrations.
  • The batteries are shock resistant.
  • AGM batteries have the ability to withstand colder temperatures than a typical wet cell battery.
  • They can be installed in any orientation.
  • The battery can produce minimal gassing and be used in less well-ventilated areas.
  • The battery offers a low self-discharge rate. Hence, you can stored them for longer before they require a charge.
  • The batter can last longer than SLA batteries if well maintained.
  • They require no maintenance.
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Cons for AGM Batteries

  • AGM’s production costs are higher, which makes them more expensive.
  • The batteries are sensitive to overcharging and high voltages. Also, they require full charging between uses.
  • The battery needs a charger specifically for AGM batteries that monitors volts, amps and ambient temperatures.
  • Some older battery testers can’t accurately test AGM batteries.

Advantages of Lithium-ion Batteries

  • The battery is lightweight and provides the same or greater energy at less than half the weight and size.
  • Lithium batteries have a prolonged service life. However, this depends on where and how the battery is being used.
  • They last 2 to 3 times longer than similarly rated lead acid batteries.
  • The battery offers a high energy density. This means that it deliver the same amount of energy but in a smaller footprint compared to a battery with lower energy density.
  • It has a low-discharge rate. Although all batteries experience some amount of self-discharge at different rates.
  • Ease of installation
  • Minimal maintenance
  • use of non-hazardous materials
  • A high level of efficiency

Disadvantages of Lithium-ion Batteries

  • Lithium-ion batteries cost 40% more than lead acid batteries
  • Lithium-ion batteries are susceptible to conditions that can damage the battery pack and need to be regulated for safety reasons,.
  • A Battery Management System (BMS) is used to avoid these damaging conditions. Therefore, the BMS shuts the battery down if it senses that the battery is operating outside of its safety margins.
  • While this might be useful in some scenarios, it can be problematic when the user needs power regardless of the possibility of the battery getting damaged in the long run.
  • Lithium batteries need to be treated more like an electrical power device than a regular battery.
  • It has current output limits, charge limits, temperature and voltage limits that will turn the power off.
  • Battery technologies may get damaged if these limits are exceeded
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Are lithium batteries better for boats?


Lithium-ion marine batteries weighs less and are more efficient. In addition, they can last up to 10 times longer than lead-acid batteries.

Therefore, lithium batteries have become an excellent choice for boating applications.

Size & Weight Reduction

We know that all boats have a weight limit, and reducing the weight is vital. On average, lithium batteries are about half the weight of lead-acid batteries with the same capacity.

Increased Number of Charge-Discharge Cycles

Deep-cycle lead-acid marine batteries last between 500-1,000 charge-discharge cycles. Also,  the lifecycle of a lithium marine battery is usually between 3,000-5,000 cycles.

Furthermore, the lifespan of a lead-acid battery depends on how well you maintain the battery.

Lithium-ion batteries require no maintenance to optimize their performance and lifespan.

Is Lithium battery better than AGM?

We can tell you that every battery can degrade over time. However,  lithium-ion batteries outlast AGM.

Factors like a larger depth of discharge make lithium-ion batteries more resilient and help these batteries go up to six times the life cycles of AGM alternatives

Are AGM batteries good for marine use?

AGM batteries have features that make them the best choice for marine applications. Some of the factors that make them better include their vibration resistance which ensures that they can stay in harsh conditions.

Can lithium batteries start a boat?

Lithium ion boat battery can fully charge of outboard, power your trolling motor, and offer juice to your electronic.

Can you replace AGM battery with lithium?

You can replace lead acid batteries with lithium in marine and RV applications. However, you should learn how to achieve this because there are factors that make it possible.

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How to choose a lithium battery for a trolling motor

A lithium boat battery for trolling motor is the best to choose or use with trolling motors. Meanwhile, you have to make sure you have a compatible voltage.

Ensure that you select a lithium battery with sufficient capacity to keep the trolling motor running.

For a 12 volt trolling motor, the amp hour capacity of the battery should be equal to or greater than the pounds of thrust of the trolling motor, as shown below:

  • 20 to 55 lb motor thrust: 50Ah battery capacity (or greater)
  • 70 to 112 lb motor thrust: 100Ah battery capacity (or greater)

If you have doubts about this, you have to get a battery with at least 100Ah, since that is usually enough to last a whole day with a 12 volt motor, unless you’re mostly planning to spend only a few hours on the water at any one time

Finally, we can only enjoy the best of our machines if we have the right battery. Are you still wondering about the battery to use after reading this article?

We believe that you can comfortably pick the right battery for your boat now.