Other than the Bolt series of charging problems on badly made cells, how many lipo4 packs caught fire just doing normal operation last year out of how many installs? Punctures, compressions, and inversions of the container are not normal operations as is overcharging or other abuses. I am fond of pointing out that I have run my Volt pack for the last ten years without of the predicted by pundits nuclear Armageddon, but then again I havent poked, shorted them, inverted them or mishandled the voltage points. If your electric boat pack is on fire, I suspect there's bigger problems occuring than attempting to toss a couple hundred pounds over the side.
Tesla modules in boat
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From the 100.03 regulations( Regulation No. 100-03: Approval of Vehicles with Electric Power Train.) referred to in the video:
"6.12.1. Under vehicle operation including the operation with a failure, the vehicle occupants shall
not be exposed to any hazardous environment caused by emissions from REESS. [Rechargeable Electrical Energy Storage System]"
This is just common sense stuff, people. Why would somebody be so superficial and unimaginative to think the engineer in the video was referring to anything else??!!
As for as relying solely on prevention to deal with battery thermal runaways, let's recall the quote the great popular philosopher, Mike Tyson: Everyone Has a Plan Until They Get Punched in the Mouth
It may be a pain to design, build, and fit a safety system into a boat, car, or aircraft. But, you really, really need to have some way of safely collecting, directing and dumping outside, over the side, out the transom the hot gasses and flames from a battery thermal runaway event. It's just common sense to protect the occupants and the rest of the vehicle.
"6.12.1. Under vehicle operation including the operation with a failure, the vehicle occupants shall
not be exposed to any hazardous environment caused by emissions from REESS. [Rechargeable Electrical Energy Storage System]"
This is just common sense stuff, people. Why would somebody be so superficial and unimaginative to think the engineer in the video was referring to anything else??!!
As for as relying solely on prevention to deal with battery thermal runaways, let's recall the quote the great popular philosopher, Mike Tyson: Everyone Has a Plan Until They Get Punched in the Mouth
It may be a pain to design, build, and fit a safety system into a boat, car, or aircraft. But, you really, really need to have some way of safely collecting, directing and dumping outside, over the side, out the transom the hot gasses and flames from a battery thermal runaway event. It's just common sense to protect the occupants and the rest of the vehicle.
You are right, battery fires are very rare, and it sounds like it is fairly difficult to get LiFePO4 batteries to ignite. Li-ion fires, though rare, do happen more frequently. As an electrical neophyte powering a boat with salvaged Tesla modules I'd say the chance of me inadvertently creating a situation were a thermal runaway happens is not zero, careful and conscientious as I may be.
I have what I think is a more elegant solution than "toss over the side". Basically pulling a lever that drops the battery box out the bottom. That lever pulling will be triggered by an over temp warning rather than a full blown fire. I hope. I can't guarantee that it will work but it's fairly simple to implement so I'll build the system in and hope to never use it.
Well, not a complete neophyte - my current experimental boat is an electric hydrofoil (using Bolt batteries, oh god!) and the last "boat" I built was an amphibious barge for transporting, and powered by, a Fiat 500e EV. Oh yeah, and I converted a little ICE outboard to electric for my sailboat. For me the design/build part is old hat. I've been doing it professionally for 50 years. The electrical stuff.. well I'm still learning. Which is why I'm here chatting with helpful experts.
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LG Chem....other manufacturers have also caught fire for the same reason, but GM had the "problem" of having sold 150,000 cars, unlike the others who were selling compliance cars.
LiFePO4 is twice as heavy as NMC. A lame step up from Pb, imo, and a nonstarter for anyone who wants the full benefits of EV performance.
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There is no safety system.
The marketing monkey was briefed by engineering that they had a prevention system for thermal runaway, he paraphrased that dangerous tidbit in an interview, and now some of you are running around thinking there's PFM in play (Pure...Magic) from a components assembler.
The reality is that a lithium fire starts when there is positive thermal feedback for an exothermic chemical reaction.
The ONLY ways to stop it are to cool the adjacent cells to below the threshhold temperature, or to poison the chemical reaction. The latter is impossible without destroying energy density of the cells.
Thermal management means isolating the cells from each other thermally. Few DIYers understand this, many DGAF.
As far as aircraft and marine systems, a planned jettison is RELIABLE. Vents merely delay a burndown and are there to prevent the sealed battery box from overpressuring and becoming a bomb.
I can't believe you quoted a dumbass punching bag on this site 🤦♂️
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Everybody has a plan until they get their ear bit off. 
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I make it a habit to generally ignore your posts on the forum, let alone quote you.
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Further your own ignorance - it's freedom of choice
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Maybe another idea to think about,
I remember reading about when NASA was first experimenting with using Lithium cells (in space)
...one concept was where they mounted each cell in its own "cubicle" (in a Honeycomb like fixture)
The "idea" was "if" any individual cell "went thermal" it would/could "gass out" until "expired"
...without effecting the other cells
...or having to "dump" the whole pack
* Think like bullets in a revolver, where/when each bullet "explodes", inside if its own chamber
...the hot gasses "shoots" out (of that chamber)
...without effecting (setting off) the bullets in the other chambers
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The point of using a lithium pack is energy density. Energy per unit volume. Yes, you can put one cell at each of your friends' and relatives' houses to let them burn out safely, but other aspects get complicated really fast and weight goes up unless you have this kind of money for your project to use super-expotic materials and alloys (weight and volume still go up, though):
![Product Rectangle Font Circle Screenshot]()
When reading such articles (for which you should cite the source, not personal recall, so the context and methods can be reviewed), you need to be able to distinguish science and engineering - they have very different objectives. Most science whiz-bang stuff is ridiculously impractical, yet interesting. "It can be shown..." and "further work may lead to..." are science favorites to keep the playtime money flowing in.
SpaceX sends a rocket up for ~1/1,000th that cost.
Imagine the lunar city you could have set up with the Artemis money and using SpaceX for launch staging of your Lunar Quonset huts in earth orbit.
When reading such articles (for which you should cite the source, not personal recall, so the context and methods can be reviewed), you need to be able to distinguish science and engineering - they have very different objectives. Most science whiz-bang stuff is ridiculously impractical, yet interesting. "It can be shown..." and "further work may lead to..." are science favorites to keep the playtime money flowing in.
SpaceX sends a rocket up for ~1/1,000th that cost.
Imagine the lunar city you could have set up with the Artemis money and using SpaceX for launch staging of your Lunar Quonset huts in earth orbit.
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Ohno, if you are going to use batteries with a potential battery thermal runaway issue, you could incorporate the safety venting system into a rudimentary rocket drive. If aimed out the back of your boat, it could get you safely to shore, if there is a thermal runaway event. It could have a properly sized low pressure blow-out disk on the battery enclosure leading into a classic low pressure rocket nozzle:
You would have to make sure the battery enclosure, blow-off disk, and nozzle are properly sized and made out of the right materials for the heat and pressures involved. This is after all, rocket science.
You would have to make sure the battery enclosure, blow-off disk, and nozzle are properly sized and made out of the right materials for the heat and pressures involved. This is after all, rocket science.
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Good idea. The nozzle design would be very simple to design vs one that's for a SSTO, in that it always will operate at, and after a few minutes, below, sea level.
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I was being serious about the concept (as an idea)Maybe another idea to think about,
I remember reading about when NASA was first experimenting with using Lithium cells (in space)
...one concept was where they mounted each cell in its own "cubicle" (in a Honeycomb like fixture)
The "idea" was "if" any individual cell "went thermal" it would/could "gass out" until "expired"
...without effecting the other cells
...or having to "dump" the whole pack
* Think like bullets in a revolver, where/when each bullet "explodes", inside if its own chamber
...the hot gasses "shoots" out (of that chamber)
...without effecting (setting off) the bullets in the other chambers
IMO being in a battery powered vessel, out in a large body of water
...has similarities to being in outer space (in a craft or self-contained suit)
...& jettisoning the entire "power" pack (or even 1/2 of it) in either situation, doesn't seem like the best idea (on several levels)
IIRC this thread is about Tesla modules
...& (again) IIRC one of the "strengths" of the Tesla modules is to still function "if" a cell "dies"
So, I think the idea was to just let that single cell "gass out" "if" one ever went thermal
...& the rest of the module would (hopefully) still be functional
To get you back to shore, in a boat
...or maybe maintain the Life Support Systems, out in space
Just "passing on" an idea that I read/heard about
...& thought it might apply to the OP's situation
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Blowing a fuse does not put a fire out.
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I don't believe "putting out a fire" is the idea here
The concept is to let "it" go on "about it's business"
...without inviting it's friends "along"
Define the parameters (of a situation)
...& then, work within those parameters
Maybe, figure out the MAX amount of energy that can/will "gass-out" of a (single) fully charged cell?
...& then (if possible) configure a structure that can withstand that abuse
I guess it could be referred to as Roman Candle style
* Don't get "gassy" (He..He..Lithium joke)
...it's just "food for thought"
The concept is to let "it" go on "about it's business"
...without inviting it's friends "along"
Define the parameters (of a situation)
...& then, work within those parameters
Maybe, figure out the MAX amount of energy that can/will "gass-out" of a (single) fully charged cell?
...& then (if possible) configure a structure that can withstand that abuse
I guess it could be referred to as Roman Candle style
* Don't get "gassy" (He..He..Lithium joke)
...it's just "food for thought"
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No.
The problem is: battery pack caught fire on a vessel that's out to sea.
Constraint: don't use passengers or self to chum for sharks
The problem is: battery pack caught fire on a vessel that's out to sea.
Constraint: don't use passengers or self to chum for sharks
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?
Pistol analogy:
In a revolver, the cylinder has to withstand the explosion of whatever caliber ammunition that it's designed to work with.
...& the barrel has to be able to handle (all of) the heat & pressure that would/could be "run" thru it
So, "if" it's a 6-shooter, the cylinder & the barrel both would have to be able to handle the MAX amount of heat & pressure that can be exerted by &/or built up when/if the gun was "maxed out" & "fired" (6) times in a row
Back to a Tesla battery module
..."if" a single cell "went thermal" what (heat & pressure) would the cell holder (cylinder) have to be able to handle?
...& then, in this "one cell per cylinder" situation, what (heat & pressure) would the exhaust shoot (barrel) have to be able to handle?
Now, "if" the bottom of a boat was designed with or as a "multi-cell holder" (cylinder) that could handle an individual cell fire
...& that incorporates individual cell "exhaust shoots" (barrel) that can handle the heat & pressure of "exhausting" those flaming gasses
Then, "if" a single cell was to gass-out
...it could/should do so, safely into the water, until exhausted
...without affecting the other cells
Just thinking "out loud"
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Your pistol catches fire while you are on your sailboat because you bought cellulose grips on sale on eBay. The steel starts glowing red...
Do you:
1) Throw it overboard
2) Hold onto it because you have good health insurance and real men can take 3rd degree burns without wincing
3) Toss it on the deck, relying on the chambers to isolate the other rounds from going off and shooting holes in the bottom of the boat
Do you:
1) Throw it overboard
2) Hold onto it because you have good health insurance and real men can take 3rd degree burns without wincing
3) Toss it on the deck, relying on the chambers to isolate the other rounds from going off and shooting holes in the bottom of the boat
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