When thinking about lithium batteries the average person jumps to things like smartphones and cordless tools, but lithium power goes far beyond what fits in our pockets.

Now widely used on boats, these powerful, rechargeable batteries run everything from action cameras and electric scooters to critical on-board systems, power tools and even outboard motors. With their promise of high efficiency and compact storage, lithium batteries make boating more convenient. Yet, despite their perks, improper use of lithium batteries on boats has led to serious accidents.

To help keep yourself and your boat safe, let’s dive into what lithium batteries are, the risks associated with improper use, and how to install and use them safely out on the water.

Cautionary tales; when lithium goes wrong

A nightmare in the back of the mind of every cruiser is losing the boat in a life threatening situation. In November 2022, French sailor Fabrice Amedeo narrowly escaped his burning racing yacht, “Nexans – Art & Fenêtres” while en route to Portugal. The culprit? A damaged ballast tank that leaked water onto lithium-ion batteries, sparking a short circuit that caused a massive fire. The boat sank soon after ignition and hours later, Amedeo was finally rescued by a cargo ship’s crew.

Sadly this isn’t a one-off story. In 2018, the yacht “Kanga” burned down near the Croatian coast. Crew members noticed a small fire in the dinghy garage, but the flames quickly spread across the vessel, forcing everyone to abandon ship. Later, investigators linked the fire to damaged lithium-ion batteries on a foil board.

In both cases, crew members hadn’t realized how much risk damaged lithium batteries pose. These stories underscore the importance of proper handling and storage.

Why lithium batteries are so powerful (and why they can be dangerous)

Lithium batteries can store a surprising amount of power in a compact space, making them ideal for small mobile devices and off-grid electrical systems. They charge quickly, last for many cycles and are lighter than comparable AGM batteries. The trade-off? High energy density comes with certain risks. When damaged or improperly stored, these batteries can release energy unpredictably, even explosively.

Looking at the structure, lithium batteries are made of several cells, each with a positive and a negative electrode separated by an electrolyte. This electrolyte carries lithium ions back and forth as the battery charges and discharges. A separator keeps the electrodes from touching directly, preventing shorts and keeping the battery working as it should. But if this barrier doesn’t do its job things can go south fast, leading to what’s called “thermal runaway.” One cell overheats, then the rest follow, creating a chain reaction that can end in devastating consequences.

Fire hazard associated with lithium batteries on boats

Before delving into this topic any further it’s important to get one thing straight; when professionally installed and used according to manufacturer instructions, modern lithium batteries are generally safe. But if they’re damaged, have manufacturing defects or are used improperly, then they can become a fire hazard.

If a thermal runaway is triggered with a lithium-ion battery (Li-on) the ensuing chain reaction causes temperatures to skyrocket, leading to flames, smoke, and possibly an explosion. Lithium iron phosphate batteries (LiFePO4) don’t react as violently as lithium-ion batteries, but can still smolder and ignite under extreme stress.

Once a battery fire starts, it’s tough to stop. These fires produce their own oxygen, making them resistant to conventional extinguishers. In smaller battery fires, cooling with water might work, but only if you can reach the battery directly. Larger lithium fires often need massive quantities of water to bring temperatures down and prevent the reaction from reigniting, or the use of specialized equipment such as a fire extinguisher specifically for lithium battery fires.

Keeping lithium batteries cool, dry, and protected

One of the best ways to protect your lithium batteries, whether they’re lithium-ion or LiFePO4, is to mitigate known risk factors.

Temperature

Temperature extremes are no friend to lithium batteries. Both heat and cold can damage them, increasing the chance of failure. Ideally, batteries should be stored in moderate conditions, away from direct sunlight and heat. This is especially important during charging, which is a high risk time. If they’re left in a hot place, like a boat deck in midsummer, the internal components can be stressed, increasing the risk of fire.

Water

As mentioned, water can be of little use during a lithium fire, and if lithium batteries get wet it can also pose a risk. This is because water can cause the battery to short circuit. As it subsequently heats up, the unit can ignite, so it’s best to ensure your lithium batteries are stored or installed in dry areas.

Deep discharge

Fully draining a lithium battery, or deep discharging them, creates another potentially hazardous situation. When a battery is fully depleted, the cells can be damaged and may spontaneously ignite during the next charge. Many modern devices do have built-in fail-safes that prevent deep discharge from occurring, but it’s best to check the battery charge level periodically and recharge before it gets critically low.

International standards for lithium batteries on boats

Navigating the waters of lithium battery safety can feel daunting, especially when it comes to following best practices. Fortunately, there are international standards designed to improve lithium battery safety on boats. The International Electrotechnical Commission (IEC), American Boat and Yacht Council (ABYC) and Australian and New Zealand Standards (ASNZ) are among the recognized groups to provide guidelines on lithium battery design, installation, and management for marine applications.

To give you some practical examples of what the standards cover, IEC standard 62619 covers safety protocols that test batteries under various conditions to ensure they can handle the marine environment. The ABYC E-13 standard emphasizes safe installation, grounding, and proper fuse selection, helping to prevent electrical malfunctions. Following these guidelines is highly recommended for boat owners looking to upgrade their vessels with lithium technology, and adherence to them is often a requirement for the installation to be covered by your yacht insurer.

Tips for safely handling lithium power on boats

Handling lithium batteries on a boat takes some extra care to ensure the installation is safe, but for many cruisers it’s worth it when weighed against the great benefits of a lithium powered electrical system.

Here’s some tips for safely handling lithium on your boat.

• Have the installation and commissioning of lithium battery house banks and battery management systems done by a professional, choosing systems and components designed to handle the marine environment
• Store or install lithium batteries in watertight spaces, protected from sun, heat and water, and install fire detectors up high for smoke, and down low for vapors
• Consider getting a fire extinguisher designed for lithium fires or lithium storage containers for portable lithium batteries
• Replace damaged batteries and don’t reuse or resell them
• Inform your yacht insurance company of the installation of a lithium battery system
• Never leave loose lithium batteries charging unsupervised for extended periods, unplug when finished charging and avoid using non-certified or knock-off chargers

What to do if a lithium battery catches fire on board

If a lithium battery fire does break out, prioritize safety. Lithium fires produce toxic gasses that pose serious health risks if inhaled, so it’s best to keep your distance and alert others. Smaller devices, like smartphones, may be able to be managed by pouring lots of water on the battery and placing it in a large water-filled container to cool the cells.

With larger batteries, like those powering water toys or outboard motors, don’t try to fight the flames directly. Instead it’s best to evacuate the immediate area and call emergency services, ensuring you tell them it’s a lithium fire. Tossing the battery overboard should be treated as a last-ditch option to protect your boat from further damage, as it is harmful to the environment, and only in spaces where it wouldn’t represent a danger to neighboring yachts.

Thinking about getting lithium?

For boaters considering a switch to lithium for powering their electrical system, modern lithium iron phosphate (LiFePO4) batteries offer a safer alternative to standard lithium-ion options, with a reduced risk of thermal runaway. However, before making the leap, it’s crucial to have a technician assess your boat’s electrical system, including wiring, fuses, and charging components. A thorough check now can prevent costly damage and safeguard your investment.

What do you think?

Lithium batteries bring undeniable advantages to modern boating, but their power comes with unique safety concerns. From understanding how to handle extreme weather and storage conditions to learning what to do in an emergency, boaters can protect themselves and their vessels by staying informed and following best practices. If you’re already a lithium battery user, share your experience! What tips or insights have you discovered for keeping these powerful devices safe and functional at sea?