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While it's technically not an ABYC violation, because they are after the fuses, the row of exposed bus bars above the battery bank, between the fuses and switches, represents poor electrical attention to detail. When I see this sort of practice on a vessel, it immediately makes me wonder what other sloppiness exists, and I almost always find it.

I always cite exposed DC positive terminals as serious hazards, especially high current, again even though insulation is technically not required by ABYC E-11 (I sit on the ABYC electrical standards committee, which includes lithium batteries, these standards are imperfect, and always works in progress, but that's another post).

Having inspected and helped design many large LFP (and conventional) battery banks and charging systems, I'm fairly well convinced that LFP batteries from respected manufacturers like MV, Victron, Lithionics and others aren't catching fire. However, because these batteries can accept sustained very high rates of charge, and discharge, they stress electrical systems in ways they were not previously stressed with AGM batteries. This means, a stainless steel washer incorrectly located under a fuse or ring terminal, on an LFP system, can lead to a fire rather than just turning purple. This places a very high responsibility on installers to avoid even the smallest errors, like inserting a stainless washer in the current path.

In this case it appears the system was at rest per se, so this scenario should not have been possible, however, such a scenario could have previously led to an overheated connection, which later arced, which in turn caused this fire.

In addition to other locations, smoke detection in the vicinity of chargers and battery banks is mandatory in my book, and for vessels of this value, smoke alarms that report remotely to an app or text, are highly recommended. If this vessel were so equipped, the fire may have been detected far sooner than the owner seeing smoke on a camera, and the source possibly eliminated. The fluctuating voltage was a clue, but there's no substitute for smoke detection. Presumably the owner's insurer didn't have a lithium exclusion. Hopefully the forensic fire investigator's report is made public, but that is unfortunately rare.

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Since the state Fire Marshall is holding off on a finding, pending the insurance investigation, I'm thinking the results will inform the state's determination of cause. So some of it will be public at least in summary form.

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If so I know you'll share it with readers.

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It's likely the fire had nothing to do with the batteries, aside from them possibly feeding power into burning conductors, that could been ignited by something else. I don't think the LFP cells in the MVLi batteries can even burn all that hot. However, in a forced overcharge, it's likely they can burn hot enough to melt and burn the plastic cases, which can create a lot of smoke which could appear like a more significant fire than is actually occurring.

A key question is which on-board breaker was it that tripped and was reset.

And the fluctuating voltage is interesting, suggesting that they should look at AC to DC charging, and possibly whatever large AC or DC loads may have been running at the time...which may have been powered by the tripped breaker; only to be reset...rather than carefully checking whatever device/load that was. It's possible they may have been able to discover the fire/heat source, before they gave it another chance to go up in smoke....

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Will be interesting to see what comes out of the investigation and updates ABYC standards. Last standard was disappointing.

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Disappointing? You mean: Don’t buy crappy batteries and follow the directions on the box.

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I do I love how the battery cable in that picture of the sistership rubs up against that rod and frame holding the batteries in...

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I don't get the point of this article. You say you don't know the type of battery, yet you clearly show pics of a certain brand that is lifepo4. And you don't say for certain what started the fire. I mean... really?

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You know for sure the battery brand?

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https://www.mastervolt.com/products/li-ion/

I immediately recognized them as Mastervolt lifepo4 batteries.

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Thank you

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After reading this it is not clear to me if these were LiFePO batteries or Lithium Ion batteries.

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Not clear to me either but it was built in the last two years, so most likely LiFePO4. The investigator isn't talking. I will put something in the story that notes the uncertainty.

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All LFP batteries are lithium ion batteries, but not all lithium ion batteries are LFP. As noted above, those shown in the photo are MV LFP batteries. There are other lithium ion chemistries, cell phones, cordless tools, EVs, etc., typically do not use LFP. A few marine batteries, especially those used in propulsion, use lithium cobalt, which have a high energy density but are not as inherently stable as LFP. These are the exception, large marine house banks are by and large of the LFP chemistry variety.

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As always, Peter, you are the first with the story on industry updates and events. Great article, I expect we’ll hear it from you as we get closer to the updating of ABYC’s lithium standards and protocols.

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