Lithium Batteries on Boats: Hazards, Risks and Safe Installation
A thermal runaway lithium battery fire is considered one of the most severe fire scenarios that can occur on a small vessel, comparable in risk to an uncontrolled gas fire.
Unlike most onboard fire situations, which can often be contained or managed with conventional suppression methods, a lithium battery thermal runaway event is far more difficult to control once it begins.
Modern marine battery systems, whether lead-acid, AGM, or lithium, are generally safe when installed and operated in strict accordance with manufacturer guidelines and recommended safety standards.
Buying Lithium Batteries for Marine and RV
Lead-acid and AGM batteries are long-established technologies, with their ventilation requirements and fire-related considerations well understood and thoroughly documented over time.
The main concern with lithium batteries today is the increasing number of lower-cost, lesser-known brands entering the market, often sold directly to private buyers through social media channels and online platforms, bypassing established and reputable retailers.
It is important to remember that reputable suppliers have significant accountability and risk exposure if the products they recommend fail, including potential liability and insurance claims.
As a result, they typically undertake extensive due diligence and generally offer robust, locally supported warranties on the products they sell.
Thermal Runaway in Lithium Batteries: Fire Risk Explained
Lithium batteries are generally classified under Class B fire risk categories, which means that in many standard fire scenarios, an ABC fire extinguisher may be applicable.
However, this becomes ineffective in the event of a thermal runaway within a lithium battery bank.
Once thermal runaway begins, it is extremely difficult, and in many cases impossible, to stop or fully extinguish the reaction.
A quick search on lithium battery thermal runaway incidents highlights a concerning track record in the aviation industry, where lithium cargo fires have proven particularly challenging to manage and have resulted in a number of serious safety events.
Lithium Battery Legal Liability – What You Need to Know
Recently, while speaking with someone who had built their own lithium battery bank using imported cells, it became clear they were not adequately prepared for the risk of thermal runaway, with no cell-level protection in place.
This raised an important question around insurance coverage in the event of an incident. When I spoke with two insurers, both indicated the answer would be no, cover would likely not apply. One even noted that third-party liability within a marina environment could be put at significant risk.
This leads to a serious consideration: where does that leave a private individual who is considering purchasing and installing their own lithium battery system?
It's RISK (incident at sea, marina or hardstand) verse REWARD (doing it cheaply).
Why Insurers Are Warning About Lithium Battery Installations
There have been documented incidents and even aircraft hull losses linked to thermal runaway events involving freight shipments of lithium batteries.
At the consumer level, thermal runaway is also known to occur in smaller lithium-powered portable devices such as mobile phones and laptops.
More recently, battery pack failures involving thermal runaway have been reported in e-bikes and e-scooters, including two incidents in Brisbane in March 2024. These examples confirm that the phenomenon does occur across a range of applications.
However, the key concern raised in this discussion is not simply that thermal runaway happens, but rather the lack of control once it begins.
For private individuals acting as importers and bypassing professional suppliers or certified installers, there are several important considerations to keep in mind.
The first and most critical step: confirm coverage and conditions directly with your insurance provider before proceeding.
You may find your insurance is void by installing your own lithium. Surveyors will ask you...we got asked for proof by both parties.
