Battery Backlash: Nigel Calder Weighs In on LI Technology
'We Are Not Seeing a Rash of Lithium-Ion Catastrophes'
Marine author, researcher and instructor, Nigel Calder is one of the hundreds of voices that have responded to Jonathan Klopman’s recent essay Accident Investigator Cites Lithium Liabilities. In conversation, Calder refers to Klopman as a Luddite. That is, a person inclined to resist new technology. Delivered with a smile, those were kind words compared to many reactions to Klopman’s piece on Facebook, where ill-tempered commenters actually asserted that a professional surveyor and accident investigator were not sufficiently expert to voice an opinion on battery fires. Loose Cannon believes the debate is a public service and asks that commenters try not to show your ass, as we say in Florida.
By Nigel Calder
We are surrounded by billions of lithium-ion batteries and think nothing of it. I started to add up the batteries at home: in my phone and computers, and smoke alarms, and the electric lawnmower, and the weed whacker, and the spare batteries in my desk drawer, and those in the kitchen drawer … and the number quickly ran into a couple of dozen. My homeowner’s insurance policy is silent on the subject of lithium-ion batteries. In contrast, I am beginning to hear anecdotal stories of marine insurance companies denying coverage if there are lithium-ion batteries on a boat. Is this an over-reaction?
We’ve all seen the pictures of burning Teslas and hoverboards, and some of us have seen pictures of a burned boat or two. There is no doubt that lithium-ion batteries pose their own challenges, and the fires can be spectacular. But if you look at the incidence of these fires as compared to, say, fires on cars powered by gasoline, absent specific manufacturing defects (the hoverboards) the risks are well within the boundaries of what we (and insurance companies) seem to deem to be acceptable. Why should our boats be different?
I can immediately think of a couple of reasons. The first is scale. The batteries in my house are a few watt-hours at most. If any of these were to catch fire, I could likely deal with it. The largest is in the lawnmower and I don’t keep that in the house (although I do charge the battery in my basement). It is 420 Wh. The lithium-ion battery bank I currently have in my boat is 7.5 kWh: it has almost twenty times the capacity of the lawnmower battery. If my boat battery bank catches fire, I will lose the boat. But then the battery pack in a Tesla is up to 80 kWh, and I would have no qualms about parking one in my garage, so I think we can discount scale.
The core problem I see with our boats is the inherent potential to operate lithium-ion batteries outside of their safe operating envelope (SOE). For example, lithium-ion batteries have significant temperature constraints, both at the low end (sub-freezing) and high end. At home, we are very unlikely to exceed these limits whereas they can easily be exceeded by a boat operating in a cold or a hot climate. In a car we can also exceed these limits, so the battery packs have active thermal management (heating and cooling) to make sure the limits are not exceeded. None of the lithium-ion batteries being sold for recreational marine use have active thermal management. Instead, they rely on a battery management system (BMS) to shut the battery down if the thermal limits are approached. The same goes for a number of other critical parameters such as overcharging and overdischarging. The BMS becomes an essential piece of safety equipment.
So now we get to the crux of the matter. In every other lithium-ion battery application I can think of the battery manufacturer can reasonably assume that the user will not modify the equipment and battery operating characteristics at any point in the battery’s life cycle. Recreational boats are different. Right up front, most of the lithium-ion installations are currently being done by dealers or in the aftermarket, and not by the boatbuilder, so there is less control over the installation. And then there is a high probability that over the life of the boat, owners will make additional modifications, including to equipment that can have a critical impact on the safe operation of the lithium-ion batteries. For example, alternators, voltage regulators, battery chargers, inverters… The list is a long one.
A lithium-ion battery for recreational boat applications needs to be constructed, including its BMS, such that it can handle significant potential environmental and owner abuse. It requires installation in a manner that complies with clear manufacturer instructions, and which will prevent it being used outside its SOE. Both the construction and installation requirements are problematic in as much as many of the lithium-ion battery manufacturers jumping into the boat market have little or no prior marine experience, and likely a limited understanding of the duty cycles, operating environment, and abuse potential.
We’ve dealt with these kinds of issues before. When we first started putting gasoline engines in boats, we burned up some boats. When we first started putting propane systems on boats, we blew up some boats. Lead-acid batteries can vent explosive gases and also blow up (I have the photos). We figured out how to make these installations more-or-less bulletproof and enshrined that knowledge in various standards, notably those promulgated by the Coast Guard and the ABYC.
What we need are clear standards that apply to the use of lithium-ion batteries in recreational boating. Unfortunately, this is not as easy as it sounds. Unlike most of our other standards, which focus almost entirely on the installation side of things, from a safety perspective with lithium-ion we are significantly relying on the complex electronics, and associated disconnect devices, embedded in the BMS: we are dependent on the battery manufacturer adequately addressing the possible failure modes. Because of the unique role that the battery construction and BMS play in ensuring the safety of a lithium-ion installation, any standard needs to contain prescriptions that go well beyond the installation.
In figuring out what should be in a standard and what can be left out we don’t have to reinvent the wheel: there are existing UL and European standards we can use for guidance. These include varying levels of abuse testing which can be tailored to address the consequences of most of the things that can potentially go wrong in a boat, including as a result of installer and owner errors and abuse. We can adapt these standards, and add to them as necessary, to deal with the unique context and installation challenges of recreational boating.
The ABYC has been working on this for some time, resulting in a Technical Information Report (TIR) that was released last year, and which is currently being tightened up into a full-blown standard. This should be available for public comment in 2022. A core discussion has been to what extent some of the more rigorous abuse testing in existing standards should be incorporated into the ABYC standard, and whether-or-not independent third-party testing should be required to confirm compliance with these standards (as opposed to in-house testing, which is widely used at the present time).
As we move forward with the energy systems on our boats, lithium-ion batteries are an ever more essential component. I would hate to see insurance companies becoming technology blockers through what may be a knee-jerk reaction to over-hyped lithium-ion fire stories. What is needed is an active engagement with the standards-writing process so that the unique knowledge and perspective of insurers can be baked into the emerging standard. The insurers can then require compliance with the standard, as is done with many other boat systems. This way we can collectively reinforce safety for the boating public, and minimize insurance claims, without stifling innovation.
In the interim, we are not seeing a rash of lithium-ion catastrophes so let’s not jump the gun…
Nigel Calder is author of the classic Boatowner’s Mechanical & Electrical Manual, each edition of which gets thicker, reflecting the growing complexity of onboard systems. He is founder and lead instructor of BoatHowTo.com. A version of the essay above first appeared in the February-March issue of Professional BoatBuilder magazine.
Battery Backlash: Nigel Calder Weighs In on LI Technology
Good to see Nigel Calder making comment here. Peter, you are performing a genuine service by stimulating and hosting this discussion. That said, one fact which emerges above all others is that Lithium batter installations on boats and yachts are not a matter for by-guess-and-by-golly DIY-ers whose knowledge and experience is derived from the posts on Facebook.
If only all public discourse was as thoughtful, respectful and even-handed the world would be a better place! Thank you Nigel and Peter. I've been following many Li-ion discussions and this was by far the most insightful for a boat owner with modest DIY skills.