When I considered writing this article I thought, “I’m not qualified”. Then, I thought most of my readers aren’t either, so I would write it in simple terms. And, frankly, I had no other option.
I have been a marine surveyor for 36 years and have inspected many battery installations. I am familiar with the ABYC recommendations regarding battery installation that are most relevant to the trade.
One year ago, I purchased a boat equipped with lithium batteries, I hired an expert to inspect the system to ensure it was properly installed and to determine the condition of the batteries. Recently, one of my customers asked me to submit a report regarding the installation of his lithium battery system to his insurance underwriter, and he said they simply needed to know if it was in compliance with ABYC recommendations.
As an aside, ABYC stands for American Boat & Yacht Council, an organization who developed and maintains recommendations for a multitude of systems and components on recreational vessels. We have found that, while ABYC provides a great number of useful ideas, it is difficult to learn, know, and apply all of them. Many of their recommendations cross-reference other ABYC recommendations, other standards, and use technical jargon and words that are familiar only to specialists in that field.
In response to the clients’ request, I reviewed ABYC E13, a recommendation regarding lithium batteries dated August 2022, and applicable to systems manufactured or installed after July 31, 2023, with over 600 watt-hours. In ABYC terms, this is an infant recommendation. I have read articles over the years, and I spent a half-hour on the phone with the expert who inspected our boat’s lithium system.
I am not going to discuss the various types of lithium batteries, chemical compositions, or physical characteristics of the batteries. I will present what I feel are useful take-aways from my experience and research.
The advantages of lithium batteries, specifically the amount of power to weight in space are significant, and they help solve many common battery problems boating. A lithium battery system is more expensive than any of the more traditional battery systems, particularly if it is installed with the recommended redundant safety components. Lithium battery systems can be safe and the probability of a “runaway” condition (think fire that cannot be extinguished) is negligible.
Every lithium battery requires a battery management system to control the rate of charge and discharge. Improperly regulated charging and discharging will lead to the diminishment of service life and may lead to the dreaded “runaway” condition. This is what causes those fires that make headlines.
The water being sprayed on those lithium fires you see in the news is just trying to dissipate heat, it can’t extinguish the fire.
Historically, fires have been caused by lithium battery systems, and they have been well-publicized. As they are nearly impossible to extinguish, the concern among marine insurance underwriters is valid.
Most of the lithium batteries for sale on Amazon come with an internal battery management system (BMS). This does not make them “plug and play”. Consider their ability to communicate with each other by design before installing multiple battery systems. Thoroughly research the type of overcurrent protection devices necessary if the BMS fails and where they should be located.
My expert analogizes installing a bank of internally regulated lithium batteries to herding cats. Not only do you have multiple batteries with their own BMS, but many have no sensing or monitoring systems to provide the boat owner any information as to the health of the system.
My expert believes that an external battery management system is superior for many reasons, but the proper installation requires more sophistication and expense.
One of the most challenging ABYC recommendations is E-11-10, which recommends that all ungrounded conductors need a suitable overcurrent protection device within seven inches of the power source. These overcurrent protection devices must have the amperage interrupt ability (AIC) required by the lithium battery, which may be a Class T fuse (think pricey). Lithium batteries have a temperature range approximately 40-120ºF. It must be restrained, which means they do not move if you tug on them and installing them with other types of batteries is extremely complicated, and requires specific equipment, particularly with respect to charging.
Buying a lithium battery and installing it as if it is a replacement for a traditional battery is a mistake. If you have a proper level of experience and sophistication in electrical systems, which means you understand the acronyms BMS, AIC, SOE, ABYC, and Class T fuse, you should not do the installation.
I declined to write the report for the underwriter for the client’s lithium battery system. I feel it is beyond my skill set and know it is past my comfort zone.
My expert is Jim Dixon at Dixon Group Inc., a distributor for Victron and other brands located in San Diego, CA. Contact them at (619)851-8260 and hello@dixongroupinc.com.