Lithium Batteries on Boats: A Safety Checklist for the Season Ahead

Marine safety

Boating season is here, and there is more lithium on board than ever: house banks, electric outboards, winches, e-foils, e-bikes on deck and a power bank in every bag. On land, a battery fire is something you get away from. On the water, there is often nowhere to go.

What can go wrong

In 2023, a berthed charter fishing vessel in Australia was destroyed by an explosion at 11:30 at night. The owner had been having trouble with a lithium battery system that wasn't holding charge, and a new charger had been connected that afternoon and left running overnight. Investigators found the charging set-up had likely bypassed the battery management system, and that the battery location wasn't ventilated as the Australian Standards require. The blast threw debris up to 30 metres and ejected a 200 kg deck winch. Nobody was on board, but the vessel was beyond repair (Australian Maritime Safety Authority [AMSA], 2024).

AMSA also points to the 2019 loss of the dive boat Conception in California, where 34 people died. Unsupervised batteries on charge were one of the likely ignition sources (AMSA, n.d.). And in July 2023, a lithium battery fire at a marina in the Florida Keys killed one person and critically injured two. An e-bike had fallen into the water earlier that day, and its battery was then stored in a wooden cabinet alongside flares (Yachting World, 2025).

Why these fires are different

A lithium-ion cell in thermal runaway generates its own heat and drives neighbouring cells into failure. The UK's Royal Yachting Association warns that these fires spread quickly, that traditional extinguishers may not work on them, and that keeping escape routes clear is essential (Royal Yachting Association [RYA], n.d.). The smoke is a hazard in its own right: a 2025 U.S. Coast Guard research paper found toxic gases often make up 60 to 70 percent of emissions, with hydrogen fluoride and carbon monoxide reaching levels immediately dangerous to life or health (MarineLink, 2025). In a cabin or an engine bay, that happens fast.

An onboard checklist

• Get installations done properly. Fixed lithium systems should be installed by a competent person to the Australian Standard, with an approved battery management system (AMSA, n.d.).
• Never work around the BMS. Use the charger the battery maker specifies, and treat any battery that won't hold charge as faulty, not as a charging problem to be solved overnight.
• Charge portable devices away from where people sleep, supervise them, and unplug when full (AMSA, n.d.).
• Charge in a fireproof container. AMSA recommends it for onboard charging (AMSA, n.d.), and a containment bag is the simplest way to do it for e-foil packs, power banks and spares.
• Inspect before every charge. Don't charge a battery that is damaged, swollen or hot to touch (AMSA, n.d.), and treat anything that has been dunked in salt water as damaged.
• Keep batteries out of the sun and away from flares, fuel and other flammables.
• Fit a working smoke alarm and keep escape routes clear (RYA, n.d.).
• Brief everyone on board. Guests should know where devices charge, where the extinguisher is, and what to do if a battery starts hissing, smoking or swelling.

If a battery fails on board

Move people away first. A lithium-ion extinguisher can knock down a small fire in its early stages, but an established battery fire on a boat is a reason to get off, not to stay and fight. Call 000, or issue a Mayday on VHF channel 16 if you're under way. Carry lithium-specific equipment as an addition to your required marine safety gear, not a replacement for it.

For marinas and clubs

Pontoon charging, stored e-bikes and damaged batteries left on board are now part of a marina's fire risk. A clear policy on onboard charging, a quarantine point for damaged packs and lithium-specific equipment at the fuel dock and hardstand go a long way. Our Marinas & Boats page covers site set-up, and our Lithium Battery Fire Safety on Boats course gives owners, crew and staff a shared baseline, with group access for clubs and marinas.

Containment bags and fire blankets contain and buy time. They do not extinguish thermal runaway. In any battery fire, get clear and call for help.