Fire on dive boat Conception in CA

[ericinmich]

Or the fire was smoldering and the detectors didn't go off at all (note the 55% failure rate for smoldering fires)
nbc5

until it eventually flashed over rapidly.

Plus, a smoldering fire with windows open could easily keep the wind moving away from a detector.

 

[Mindless]

I alway use one of the fireproof Li-Po bags when traveling with Lithium Ion batteries and, while on board, charge the batteries inside the bag in the hopes of minimizing the risk of fire. I also don't buy cheap knock-off batteries.

 

[Louisville Diver]

There was a comment by someone familiar with the boat that "the generator always runs". Someone else familiar with the boat suggested an issue with the boat batteries. The prevailing theory here seems to be a Lithium Ion battery fire in the main cabin.

The investigation will have to determine that. Along with how it spread so fast. I've seen heard several people talking first hand about how fast boats can burn, so this may just be how fiberglass burns once you get it going.

An old new article said it had a steel hull. The hull shortly before it sank looked like it had suffered extensive damage from the fire - and steel needs to get really hot to melt - so maybe it was fiberglass or aluminum.

Something dawned on me this morning. My newer batteries tend to recharge via USB, which I'm assuming is always a protected circuit. Older batteries were direct plugins.

I'm wondering if someone was charging an older-style battery by a 110 plug either into an unprotected circuit OR a surge strip that was past its prime (I've had to replace some - you should see the warping when they croak). You'd get some sort of amperage spike straight into the battery that way.

 

[dmaziuk]

I alway use one of the fireproof Li-Po bags when traveling with Lithium Ion batteries and, while on board, charge the batteries inside the bag in the hopes of minimizing the risk of fire. I also don't buy cheap knock-off batteries.

Trickle-charge them at < 0.5C (edit: for less) temperature build-up. They'll live longer.

Something dawned on me this morning. My newer batteries tend to recharge via USB, which I'm assuming is always a protected circuit. Older batteries were direct plugins.

USB 2 is 0.5A and at that current you shouldn't see much heat build-up during charging, but USB 3 is specced to 0.9A and "charging" ports can easily go to 2A. That's "fast charge" territory already -- though I'm told RC crowd runs theirs chargers at 4 amps and somehow they don't blow themselves up all that often.

 

[KevinNM]

High power batteries need a lot of power to recharge at a decent rate. And USB connectors are not suitable for some usage. My primary light has a purpose built charger that connects to exposed metal studs on the light body.

But batteries sometimes just fail. The series of issues and fires boeing had with the 787 batteries were kind of a demonstration of this. These were highly engineered and carefully built ‘cost is not a problem’ units and still several caught fire.

 

[rjack321]

Trickle-charge them at < 0.5C temperature build-up. They'll live longer.

C in lithium ion charging terminology refers to capacity not temperature Celsius. Lithium ion are best charged around 0.5C ie 1/2 of the C rate.

Charles-Augustin de Coulomb's C-Rate for Batteries

Charging Lithium-Ion Batteries

PS most chargers supplied with lithium ion devices have several protection circuits built in to avoid overcharging. In this case, on a 40 year old vessel, there's probably a greater chance of a hidden wiring issue with a smoldering fire going undetected until flashover vs a sudden lithium ion battery explosion. But hopefully we will find that out in time.

 

[Compressor]

Staff Member Note:

Please keep the discussion focused; if you want to educate others about topics not related to the accident that has happened, please PM the user you intend to correspond with separately.

Thank you for your understanding.

 

[DebbyDiver]

Respectfully, while I understand wanting to give support to the dive company, I think it's important to review the investigation when it's complete and see where change might need to be made.

And I don’t think it’s being cavalier to agree that I’d go on these boats tomorrow. I remember years back with the “drifting dan” incident off the Sundiver, I also had no qualms about going going on that boat the next week. What happened there, as here (different scale I acknowledge) was so completely out of the norm and such an aberration that the odds of a recurrence were infinitesimal

I'm neither supporting the dive op, as I don't know them, and not being cavalier. The chances of this happening again are small, and I'm positive that dive ops will increase crew vigilance exponentially.

 

[dmaziuk]

C in lithium ion charging terminology refers to capacity not temperature Celsius. Lithium ion are best charged around 0.5C ie 1/2 of the C rate.

Charles-Augustin de Coulomb's C-Rate for Batteries

Charging Lithium-Ion Batteries

Yes, sorry. In the first approximation, roughly, etc. if you fully (dis-)charge a 1 ampere-hour battery in 30 minutes, you have to push in 2 amps -- or out, if you're discharging. This rate will result in much larger temperature build-up in the battery itself, than (dis-)charging the same battery in 2 hours at 0.5A. Heat will shorten the batttery's life and also increase the probability of it going boom in the process.

What's relevant to the topic is that during charging the energy has to come from somewhere: the boat's generators and/or battery banks need to supply those amps to the outlet the charger's plugged in. Anywhere in between where there's a connection, there can be sparks and heat build-up, not just in the battery itself.

 

[Esprise Me]

Lithium batteries are still allowed in carry-on luggage, correct? I'm mainly thinking of the ubiquitous 18650 Li-Ion cells that are used by many dive lights and the high capacity cells in video lights.

Lithium batteries with more than 100 watt hours

Once we figure out what those lessons are. Right now the only clearly obvious one is that serious reconsideration of the rules about emergency exits needs to be done. I suspect others will be found as the investigation proceeds.

I don't think even that much is obvious yet. It may yet turn out that the fire grew so quickly no escape was possible regardless of the state of the exits, or it killed people before they woke up. I would be interested to know how long it takes to evacuate that cabin under various circumstances.