This post was originally posted at the blog at Dragonfly Energy.


More and more boaters are making the switch to lithium marine batteries and for many good reasons! Let’s take a look at the benefits of lithium marine batteries and answer some frequently asked questions.

lithium marine batteries

Why Boaters Are Choosing Lithium Marine Batteries

Lithium-ion marine batteries are more efficient, weigh less, and can last up to 10 times longer than lead-acid batteries. Combining all of these features makes lithium batteries an excellent choice for boating applications.

Size & Weight Reduction

All boats have a weight limit, and it’s no secret that reducing the weight you carry on your boat is important. On average, lithium batteries are about half the weight of lead-acid batteries with the same capacity. 

For example, a Dragonfly 100 Ah lithium battery weighs about 31 pounds. An average 100 Ah lead-acid battery weighs between 60 and 80 pounds, depending on the type of battery

Increased Number of Charge-Discharge Cycles

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

Additionally, the lifespan of a lead-acid battery is dependent on how well you maintain the battery. Lithium-ion batteries require almost no maintenance at all to optimize their performance and lifespan.

boat at marina

Increased Power Storage

Draining a lead-acid battery below 50% of its capacity causes damage and shortens the battery’s life. Conversely, most lithium battery manufacturers rate their batteries to allow 80% depth of discharge. The batteries we manufacture can be 100% discharged without causing damage.

The increased power storage is one of the best benefits of lithium batteries. Since you usually get almost double the capacity, you may only need half the batteries. Half the number of batteries, when each battery weighs half of what a lead-acid battery weighs, results in almost a four-times reduction in weight!

Cheaper Long-Term

The upfront cost of purchasing a lithium marine battery is significantly higher than buying a lead-acid battery. However, lithium batteries often last at least five times as long as their lead-acid counterparts.

Their longer lifespan combined with their increased efficiency makes lithium-ion marine batteries cheaper in the long term. Plus, remember that you may only need half as many lithium batteries as you had lead-acid batteries.

lithium marine battery on boat

Is It Easy to Make the Switch to a Lithium Marine Battery?

Many lithium batteries are drop-in replacements, meaning that they’re designed to fit like a typical lead-acid battery in your battery bank. However, it’s not always plug-and-play. You may need additional components to complete your installation. 

Depending on your use and application, you may need to upgrade your inverter and battery charger to maximize performance. Additionally, lithium batteries don’t have any warning signs they’re about to die, so you may also need to add a battery monitor as well. 

Most of these changes are relatively straightforward; however, errors in electrical systems can be dangerous. If you are not confident in your ability to make the switch to lithium marine batteries on your own, please get in touch with a professional.

How Long Do Lithium-Ion Marine Batteries Last?

Lithium marine batteries will typically last 3,000-5,000 charge cycles. This usually translates to lithium batteries lasting ten years or longer.

In fact, here at Dragonfly Energy, we offer 5-year warranties on our lithium batteries. Conversely, most lead-acid manufacturers offer warranties between one and five years.

boats moored in bay off grid

Are Lithium Batteries Safe on Boats?

Yes, lithium batteries are safe for marine and boat applications. Lithium batteries are sealed, which means that moisture and even a bit of water splashing on them will not cause harm. 

Additionally, most lithium batteries have an internal battery management system (BMS). The BMS will detect unsafe conditions and shut down the battery to prevent damage or thermal runaway.

How Expensive Are Lithium Marine Batteries?

Lithium marine batteries usually cost around $1,000 for a 100 Ah capacity battery. The upfront cost is significantly more than the lead-acid counterparts available, but the overall long-term cost is lower.

Is Upgrading Your Marine Battery to Lithium Worth It?

We’ve said it a few times: lithium-ion batteries are quite a bit more expensive than their lead-acid counterparts. However, for the added cost, you enjoy the benefits of significant weight reduction, increased efficiency, added safety, and a much longer lifespan.

When you factor everything in, not only are lithium marine batteries actually cheaper in the long run, they’re absolutely worth the investment.

The post Why Boaters Are Choosing Lithium for Their Marine Batteries appeared first on Dragonfly Energy.

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