On May 8, 2025, at 6:01?AM, Nauset Beach via groups.io <nausetbeach@...> wrote:

Thanks Dave, Pete and Tim.? To say this is an evolving field may be an understatement.? It seems odd the battery User Manual cites Class D extinguishers first in their list, followed by sand and dry chemical.? Possibly a “CYA” ?legal department phrasing??? I have 6 dry chemical A/B/C extinguishers accumulated over a few years, so one might think that would be adequate.? Will check the ages; had not heard of a 12 year life.? Was that a surveyor criteria, ABYC &/or insurance company requirement? ?Thought only requirement was the gauge be in the green.? And recommended to shake them periodically to prevent caking of the chemicals.??

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Guess my concern is some underwriter will latch on to the Class D mentioned by the battery manual, which seems superfluous if not ineffective.? Especially as there are different types of Class D extinguisher, one of which is specifically not recommended for lithium batteries.??

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I learned first hand about epoxy exothermic reactions decades ago when mixing too much epoxy on deck when filling bolt holes prior to redrilling to better seal the deck penetrations. ?After that always had a larger contain of water available and mixed smaller quantities.??

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Thanks,

Brian

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From:?[email protected]?<[email protected]>?On Behalf Of?David Lochner via?
Sent:?Wednesday, May 7, 2025 9:18 PM
To:?[email protected]
Subject:?Re: [SabreSailboat] Class D Fire Extinguisher for LFP ?

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There is a big difference between a “normal” fire and thermal runaway. LFP batteries are not subject to thermal runaways, if damaged, the electrolyte in the cells can burn in a “normal” way. In a normal fire there are 3 essential ingredients, oxygen, fuel, and heat. In thermal runaway the chemicals in the battery cells react with each other and in the process produce heat that is accelerated by heat, the generates heat which makes the reaction go faster thereby generating more heat which makes the reaction go faster and so on. Once this happens there is no way to stop the reaction, all that can be done is to contain the heat and prevent it from igniting something near buy. Designing a fire resistant space for the batteries and then flooding that space with water will contain it as well as the vermiculite extinguishers mentioned by another member which insulate the battery from combustible material. ?None of this matters for LFP batteries because they can’t go into thermal runaway.

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To see an example mix some epoxy on a warm day and put it in a small cup. As it reacts and cures it generates heat this causes the reaction to go faster and the epoxy start bubbling and foaming.

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When I was recently surveyed, the survey wanted to make sure i had he right number of Marine rated extinguishers and they were all current, i.e., not more than 12 years older than the year embossed on the bottom of the tank.

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Dave

Second Star

S362 #113

Fair Haven, NY/Lake Ontario

On May 6, 2025, at 4:58?PM, Nauset Beach via??<nausetbeach@...> wrote:

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The new LFP batteries are on board and getting connected today, along with a MultiPlus and Orion.? Solar in the next week.? In reading the user’s manual for the batteries it recommends if there were to be a fire involving the batteries to “use a Class D extinguisher, sand or a dry powder extinguisher.”? I have multiple dry powder A/B/C extinguishers.? Out of curiosity, does anyone with LFP batteries have a Class D extinguisher on board? ??

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A quick search seemed to indicate LFP were a Class B type due to containing liquid electrolyte while Class D extinguishers were for metallic lithium and not for LFP batteries. ?The copper extinguishing agents used in some Class D were specifically not recommended for LFP batteries.? Sodium chloride Class D extinguishers were silent on LFP’s.??

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Am trying to anticipate what issues the insurance underwriters may raise, and if by getting the proverbial ducks lined up may improve the process.??

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Thanks,

Brian

Escapade? S426

CT / LIS

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