LIFEPO4 Smoke and Fire Dept

[RV10flyer]

I've mistakenly left nuts loose getting in a hurry. The BMS always picks it up. It may show cell number 10 with an error but it could be cell number nine or 11. If you see a faulty reading, you better start looking over all your connections and crimps.

Also install a sticky note with your typical voltage difference at maximum pack voltage. When my Sol-Ark's are in absorption phase, pushing 370A in, I'm usually watching voltage difference. All 10 batteries are different, but if you start seeing them change you better start investigating.

 

[acdoctor]

It’s interesting that the cell that failed is the only one that interconnected all three shelves. The nuts were definitely not tight enough to hold the buss bars from movement from the swelling. But I am not sure how much force is involved.

 

[chess-equality]

What is the best practice with swelling? Must be prevented at all costs?

I have 4 x 12v serviceable batteries as backup and I'm planning to take out the cells to combine them into 48v in the near future.

 

[rhino]

What is the best practice with swelling? Must be prevented at all costs?

I have 4 x 12v serviceable batteries as backup and I'm planning to take out the cells to combine them into 48v in the near future.

Keeping the voltage of every cell between spec and limiting to 0.5C or less charge/discharge.

 

[RV10flyer]

Keeping the voltage of every cell between spec and limiting to 0.5C or less charge/discharge.

Rigid endplates and two 1" cargo straps, installed before charging above 3.28 or 30% cap that cells are shipped with. It works great for me.

 

[realpinochet]

just prompted me to recheck my battery and 1 terminal wasnt very well tight and the busbar was clearly hotter on that 1 terminal. I bet you had a similar issue. 1 loose terminal, lots of resistances, lots of heat, boom

Aside from using a torque wrench when installing ..would lock washers on each terminal help to keep them from loosing over time? Since the washer puts presser against the screw in theory it should work like it does in auto and other mechanics applications.

 

[rhino]

would lock washers on each terminal help to keep them from loosing over time

Would be better to use a stainless steel serrated flange locknut.

 

[32 volt boater]

And that's why they still use lead acid on submarines. And no lithium on my boat.

The Attack-class submarine battery debate: science fiction or engineering? | The Strategist

In view of Derek Woolner’s warning last month that the Royal Australian Navy’s new Attack-class submarines will be obsolescent by the time they’re delivered, it’s time to revisit the main storage battery question—including what we’re ...

www.aspistrategist.org.au

Long odds but a cabin full of smoke and no place to run no thanks.

I was thinking of building one https://diysolarforum.com/threads/i...epo₄-battery-for-boat-very-new-at-this.45598/

Maybe on the deck in a metal box someday but lead works fine.

 

[mrzed001]

And that's why they still use lead acid on submarines. And no lithium on my boat.

The Attack-class submarine battery debate: science fiction or engineering? | The Strategist

In view of Derek Woolner’s warning last month that the Royal Australian Navy’s new Attack-class submarines will be obsolescent by the time they’re delivered, it’s time to revisit the main storage battery question—including what we’re ...

www.aspistrategist.org.au

Long odds but a cabin full of smoke and no place to run no thanks.

I was thinking of building one https://diysolarforum.com/threads/i-want-to-build-a-32v-lifepo₄-battery-for-boat-very-new-at-this.45598/

Maybe on the deck in a metal box someday but lead works fine.

The article is old ... and a joke.
It only considers Li-ion (NMC/NCA) batteries.
Like never heard of LiFePO4, LTO.

An LFP battery can at most let out smoke. It is easy to put them in an air tight cabin (problem? solved !).
But a lead-acid battery can EXPLODE.
Now that is something I definitely do not want to happen in a closed metal can under the water ....

 

[BobR]

And that's why they still use lead acid on submarines. And no lithium on my boat.

The Attack-class submarine battery debate: science fiction or engineering? | The Strategist

In view of Derek Woolner’s warning last month that the Royal Australian Navy’s new Attack-class submarines will be obsolescent by the time they’re delivered, it’s time to revisit the main storage battery question—including what we’re ...

www.aspistrategist.org.au

Long odds but a cabin full of smoke and no place to run no thanks.

I was thinking of building one https://diysolarforum.com/threads/i-want-to-build-a-32v-lifepo₄-battery-for-boat-very-new-at-this.45598/

Maybe on the deck in a metal box someday but lead works fine.

"Power cables in Bonefish’s forward battery well were sparking and glowing cherry red, small flames and electrical arcs licking across the battery bus. A petty officer rang the alarm “Fire on third street!”



The crew frantically blasted CO2 fire extinguishers to cool the overheating battery but the flames continued to grow and light smoke began wafting across the submarine began surfacing to periscope depth. Nine minutes later Bonefish’s skipper ordered the hatches to the battery compartment sealed, hoping to starve the flames.


But even as damage control crews struggled to comply, there was an explosion and a fireball coursed across the compartment, blasting sailors against the wall. In moments, jet black smoke poured across the ship, blinding the crew and making breathing poison."

A Fireball: This U.S. Navy Submarine Was On Fire Underwater

Fortunately, most of Bonefish’s crew miraculously escaped the calamity with their lives—but that doesn’t lessen the tragedy of the three crew members who were not so fortunate.

nationalinterest.org

 

[chess-equality]

I think the military doesn't use non-military certified products (such as MIL-STD-*), so they're still using LA.

United States Military Standard - Wikipedia

en.wikipedia.org

This one's on lithium and dubbed "the most advanced", with the highlight on using lithium.

Japan's Jumbo New Submarine Runs on Lithium-Ion Batteries

The same tech that powers your phone also propels one of the most advanced subs in the world.

www.popularmechanics.com

 

[chess-equality]

"Power cables in Bonefish’s forward battery well were sparking and glowing cherry red, small flames and electrical arcs licking across the battery bus. A petty officer rang the alarm “Fire on third street!”



The crew frantically blasted CO2 fire extinguishers to cool the overheating battery but the flames continued to grow and light smoke began wafting across the submarine began surfacing to periscope depth. Nine minutes later Bonefish’s skipper ordered the hatches to the battery compartment sealed, hoping to starve the flames.


But even as damage control crews struggled to comply, there was an explosion and a fireball coursed across the compartment, blasting sailors against the wall. In moments, jet black smoke poured across the ship, blinding the crew and making breathing poison."

A Fireball: This U.S. Navy Submarine Was On Fire Underwater

Fortunately, most of Bonefish’s crew miraculously escaped the calamity with their lives—but that doesn’t lessen the tragedy of the three crew members who were not so fortunate.

nationalinterest.org

...which battery was the source of the grounding issue at the same time as leaking seawater was detected.

....allowed saltwater to flood across the ship, corroding the joint where battery cables penetrated the deck.

The battery wasn't the culprit in this case.

 

[realpinochet]

 

[MattiFin]

Would be better to use a stainless steel serrated flange locknut.

Use bellewille washers aka disk springs.
disk spings help to maintain the clamp load in the joint and that is the important part. Serrated nut can ”dig in” with time. It wont rotate loose but it doesnt provide original clamping load neither.

bolted joints usually work better when bolt under tension is longer and it is torqued close to yield point. (Bolt works as a sort of spring)
but the terminal bolts are very short AND because of soft aluminium terminals the bolts are torqued to only a tiny fraction of yield strenght. End result is that even tiniest movement or creeping(cold-flowing of metal) causes the joint to became loose.
Belleville washer provides the clampingforce even if the joint moves or settles.

 

[mptx]

Use bellewille washers aka disk springs.
disk spings help to maintain the clamp load in the joint and that is the important part. Serrated nut can ”dig in” with time. It wont rotate loose but it doesnt provide original clamping load neither.

bolted joints usually work better when bolt under tension is longer and it is torqued close to yield point. (Bolt works as a sort of spring)
but the terminal bolts are very short AND because of soft aluminium terminals the bolts are torqued to only a tiny fraction of yield strenght. End result is that even tiniest movement or creeping(cold-flowing of metal) causes the joint to became loose.
Belleville washer provides the clampingforce even if the joint moves or settles.

What material would you recommend these be made of? Copper lug or bus bar and potentially an aluminum battery terminal…. Would 304 stainless steel be appropriate?

 

[MattiFin]

What material would you recommend these be made of? Copper lug or bus bar and potentially an aluminum battery terminal…. Would 304 stainless steel be appropriate?

Doesn’t really matter unless you install your batteries under sea water spray. And in that case you get plenty of other problems also. galvanized or 304 would work nicely, uncoated carbon steel gets easily some rust spots but few rust specks would be only eyesore.

 

[rhino]

Which one exactly of these are are you referring to? https://www.mcmaster.com/disc-springs/

 

[BobR]

The battery wasn't the culprit in this case.

In most cases of Lifepo4 it isn't the battery either. As in this case it was a problem with the wiring to the battery; in this incident the wire was grounded to the metal deck.

The battery wasn't the culprit in this case.

 

[chess-equality]

In most cases of Lifepo4 it isn't the battery either. As in this case it was a problem with the wiring to the battery; in this incident the wire was grounded to the metal deck.

If that was the case, then it was not the submarine's fault either, nor the fact that lead batteries are used by the submarines. It can be any battery and will still catch fire.

 

[BobR]

If that was the case, then it was not the submarine's fault either, nor the fact that lead batteries are used by the submarines. It can be any battery and will still catch fire

Like most accidents the problem starts with a small problem and then it escalates (the domino theory).

Submarine batteries are like LifePo4 batteries in such that they are individual cells connected by buss bars/ cables.
In this case a cable corroded and shorted to the metal deck; much as a lifePo4 cell shorting to a metal frame work; or a loose connection on a buss bar.

Consequently in the case of the submarine a cell or cells exploded due to the Hydrogen they produce being ignited by fire caused by arcing wires.

My point being is that in either case things can go wrong with all batteries.