What deck crew need to understand about battery use on board.
Yachting has seen a massive increase in the use of batteries and the toys they power. Over the last five years, our tender garages have been filled with Seabobs, hydrofoils, e-bikes and e-scooters, with more inventions no doubt to come. The MCA supplied an industry guidance document on batteries and their use back in 2023, which saw a large overhaul at the start of this year. Batteries (specifically lithium-ion) are relatively new to most mariners’ repertoire of knowledge, so let’s cover some basics on best practices and most importantly, their associated fire risk.
Lithium-ion batteries, the vast majority of which we’ll be using for toys on board, consist of a “cell,” with multiple forming a “pack,” making an extremely energy-dense unit. This pack is then managed by a battery management system (BMS), typically housed inside the pack and quite small comparatively. For example, your phone will have one; they monitor and control cell voltage, temperature and charging.
Fire Risk and Prevention
Yacht fires caused by batteries have been on the rise. My crew and I even helped extinguish a fire from a charging bank on a small neighboring sailing yacht while docked. Firefighting services have also seen massive increases in house fires caused by batteries. Prevention is exponentially better than a cure; a battery fire can require thousands of gallons of water to suppress. Properly storing, charging and caring for your batteries is something deck crew need to understand early on in their career because batteries seem to be here to stay.
Charging
You must use the original equipment manufacturer (OEM)’s charger because lithium packs depend on the correct charge profile. Using a different charger, even if it works, can stress the batteries, reduce their life, trip protections, give mysterious fault codes and generally lead to headaches down the road. Unlike lead-acid batteries (your GMDSS battery bank for example), lithium-ion doesn’t like to be kept at 100 percent continuously, i.e. left on charge. It will accelerate aging and damage the battery. Once charged, unplug it. Similarly, if entering the yard, the best long-term storage is around 40 to 60 percent charge. Charge in a temperature-controlled environment, not in the sun, ideally between 59°F and 95°F. Never charge a damaged battery.
Storage
For reference, thermal runaway, i.e. catastrophic battery fires, can begin at as low as 140°F. Our engine rooms, generator and machinery spaces are likely not ideal places for batteries, and MCA recommends storage at less than 113°F as an adequate buffer. You’ve probably heard of every airline advising not to retrieve phones stuck in your seat and to instead ask for assistance. This is because physical damage can lead to thermal runaway by compromising the battery pack. This means for those not blessed with cavernous tender garages, be mindful how batteries, especially removable batteries, are stored, and if there are any items that may impact them if the boat begins rolling.
Care
Salt is not great for batteries. Before removing from watertight housings, rinse off all toys and dry thoroughly. Store batteries inside, out of sunlight and salt, and ensure the housings are watertight and the seals intact. The highest care is required for the batteries and toys that were never intended for marine environments, namely e-bikes and scooters that may be exposed to salty air, as they will have the highest risk of damage.
Signs of warping, expanding or changes in a battery’s housing and encasing are sure signs the battery has been damaged, and leaking of any fluid (the electrolyte solvent from inside the cells) is an instant write-off. The fluid may be clear and hard to notice, and some exceptionally large battery packs will have built-in cooling systems that could also leak coolant if damaged. Additionally, any sound or smell, particularly when charging is instantly suspect. I stated earlier, but it bears repeating; do not charge damaged batteries.