Fire!! Never cover LiFePO4 with wood!!!

[Hedges]

Tank looks pretty small in relation to valve. What area/volume is it good for?

Halotron LC50 (4 hr.): 3.2% (effective concentration of extinguishing agent is higher than this)
Leave the room if it goes off.

http://www.halotron.com/pdf/Halotron1_SDS.pdf

Is that an "environmental friendly" "mercury based valve"?
I doubt it contains mercury - maybe they used the word to mean "temperature".

The extinguishing agent may work best if there is a moat around what you plan to have catch fire for containment.
A friend got a small Halon extinguisher. When he spilled oil while adding to his car, it flowed down to mud-caked hot exhaust pipes and ignited.
The extinguisher put out the fire for a moment, but Halon spilled to the ground it fire re-ignited. Twice.

Your smoke detector shutting off electrical would be key, because continued application of power keeps things burning.

 

[ArthurEld]

I am suspicious that fhorst's fire was caused by a short above the busbars.
The short I had happened from an arc. That to me means shorts can happen without something making a connection.
It has been shown that arcs can happen in some spots just because molecules in air line up right.
I think these unexplained fires are caused by arcs.
I could be wrong. Maybe fhorst's fire was caused by internal damage but I still think arcs are a huge problem with these batteries

 

[ArthurEld]

Maybe it has something to do with the conductive silver paint slopped on the studs.


I'm not very experienced with electricity but I feel like I should say something when I see something dangerous.
The most damage on my short was to the negative terminal on the cell used as the main plus connection. Which may also be related because it looks to me like that is where fhosrt's short is.

Also, fhorst has talked about an unexplained electro magnetic field. I can't help but think that is related to the arcing problem.

 

[Hedges]

I am suspicious that fhorst's fire was caused by a short above the busbars.
The short I had happened from an arc. That to me means shorts can happen without something making a connection.
It has been shown that arcs can happen in some spots just because molecules in air line up right.
I think these unexplained fires are caused by arcs.
I could be wrong. Maybe fhorst's fire was caused by internal damage but I still think arcs are a huge problem with these batteries

Not at these voltages. 70V to 250V is the minimum depending on gas mixture, and only very small gaps or reduced pressure.
That would be "Paschen" breakdown, which requires E-field high enough to accelerate as gas ion until its collision with another molecule causes ionization, cascading to make breakdown.

Metal plasma, created after touching conductors, is a different story. That's a great conductor and the watts delivered can melt terminals and sustain the arc.

 

[ArthurEld]

Well, you might not have arcs shooting across your battery because of changes in the air but I think you can easily short something by putting something metallic between a potential short but not make an actual touching connection. And arcs will fill the spaces.

When I shorted my battery I had a deep socket on a stubby 1/4" ratchet. There's not a chance in hell that I reached down and touched the busbar with the handle of the ratchet. So there was probably some kind of arc. Then when I dropped the ratchet, there's no chance that both sides landed touching the connections. So arcs had to be completing the connection.

Another time I got a shock though my ring but my ring wasn't big enough to complete the connection. So some kind of arc was shocking me.

I honestly would prefer that you guys convince me that I am wrong.

 

[Hedges]

Well, you might not have arcs shooting across your battery because of changes in the air but I think you can easily short something by putting something metallic between a potential short but not make an actual touching connection. And arcs will fill the spaces.

When I shorted my battery I had a deep socket on a stubby 1/4" ratchet. There's not a chance in hell that I reached down and touched the busbar with the handle of the ratchet. So there was probably some kind of arc. Then when I dropped the ratchet, there's no chance that both sides landed touching the connections. So arcs had to be completing the connection.

Another time I got a shock though my ring but my ring wasn't big enough to complete the connection. So some kind of arc was shocking me.

I honestly would prefer that you guys convince me that I am wrong.

You are an unwitting participant in our experiment.
It is imperative you continue.

Milgram Shock Experiment: Summary, Results, & Ethics

Stanley Milgram, a psychologist at Yale University, carried out one of the most famous studies of obedience in psychology.

www.simplypsychology.org

 

[ArthurEld]

You are an unwitting participant in our experiment.
It is imperative you continue.

Milgram Shock Experiment: Summary, Results, & Ethics

Stanley Milgram, a psychologist at Yale University, carried out one of the most famous studies of obedience in psychology.

www.simplypsychology.org

Experimenting is difficult. How do you test a class T fuse?

Arcs open so many possible shorts. And I don't know how far the arcs can jump.

 

[HRTKD]

We need the Project Farm guy (Youtube) to test fuses/breakers for us.

AIC of 50,000? We're going to test that!

 

[Hedges]

Experimenting is difficult. How do you test a class T fuse?

Arcs open so many possible shorts. And I don't know how far the arcs can jump.

Midnight has a paper describing breaker testing at a lab using a string of car batteries. That would have short-circuit current of 3000A (or less based on wire resistance.) They inadvertently demonstrated polarized breaker in wrong direction just burns.
One could use a series/parallel bank of batteries. With a trusted fuse as backup.

If I complete build-out of my circuit breaker tester with all three 3:1 transformers in parallel, I can probably reach 1000A at 40VAC for a few seconds.
I've read of a spinning generator to put an electrical impulse of 1 million amps into a railroad rail to light up defects.

My AC arc welding pulls a fraction of an inch at 80VAC and 140A.
The video of knife switch and heating element pulled several inches when used with DC. That was a few hundred volts from PV, I think.
It seems the DC arcs at higher voltages just don't stop unless quenched with sand or pulled into slots with magnetic field.

 

[ArthurEld]

I could connect a thick wire to one terminal and test everything in reach to see how far away I can hold it to make an arc.

edit: I am a scientist

 

[sshibly]

I just started to read this thread, ouch,

It is not IF but WHEN
an adverse event might happen, plan accordingly guys/gals.

 

[HRTKD]

edit: I am a mad scientist

Fixed it for you!

 

[Hedges]

I could connect a thick wire to one terminal and test everything in reach to see how far away I can hold it to make an arc.

edit: I am a scientist

With an arc welding hood on, and leather welding gear. (use bright lights so you can see what you're doing)

There will be strong UV when you drawn an arc. Can also be a blast of molten metal and plasma.
Overheating tin is a method to generate deep UV.

My arc welder is current-limited by transformer leakage inductance.
Even if welding rod gets stuck I can remove clamp. Or turn off AC switch which might be carrying 80A or so.
What if you weld a wire across lithium battery terminals?

Might be fun to do remotely, with a cell that previously got its terminals trashed.

I just started to read this thread, ouch,

It is not IF but WHEN
an adverse event might happen, plan accordingly guys/gals.

Exactly.

But remember, you're reading the comments from people who survived adverse events (so far.)

The forum does have a section for such topics. This thread just got us talking.

 

[sshibly]

I would try to use all of them except the one that shorted. Unless there is something I'm not seeing.

Op, can you point us to the pic with the wires connected where the fire originated.

 

[ArthurEld]

I have heard suspicious sounding zaps around my battery.

I think it has been demonstrated that you can point energy at a fluorescent light and make it turn on.

Also, lightning is known to jump the ground wire if it turns too much. That is what I read here somewhere

These things make me wonder. The direction of the current flow makes a difference. So some spots are more likely to arc.

 

[Hedges]

Yes, I've heard of lighting currents going straight rather than turning a corner. I don't know if that is due to high voltage or something about currents and magnetic fields.

Electrons can more easily jump off a sharp point, because E-field is higher with smaller radius. But not "holes", because they don't exist. "corona discharge". That may be the explanation for what lightning does going through a ground wire. With high dI/dt, wire inductance means ground wire is no where near zero volts, so a nearby conductor could be more attractive. Electrons get accelerated enough to ionize air molecules (Paschen), but the positive ions released move slowly and don't cause impact ionization.

fluorescent lights can be illuminated with high AC E-fields under powerlines, or by directing EM waves.

Steam radiators make funny sounds too. You may have several hydraulic and mechanical sound sources in your battery bank, and electrical breakdown of aluminum oxide/hydroxide insulators at contact points.

 

[ArthurEld]

One thing about fhorst's fire that confuses me is that the fire was above the busbar and the busbar seemed to protect the terminal.
That makes me think the heat was above the busbar not below.
And when I've seen videos of cells being shorted, they expand and blow the vent. I don't see any evidence of expanding or heat or vent blowing.

I guess a short inside the cell could cause the screw to heat up enough to start a fire but not enough to show heat damage to the terminal.

That is probably no more likely than my arc theory

 

[Hedges]

One thing about fhorst's fire that confuses me is that the fire was above the busbar and the busbar seemed to protect the terminal.
That makes me think the heat was above the busbar not below.
And when I've seen videos of cells being shorted, they expand and blow the vent. I don't see any evidence of expanding or heat or vent blowing.

I guess a short inside the cell could cause the screw to heat up enough to start a fire but not enough to show heat damage to the terminal.

That is probably no more likely than my arc theory

The picture I focused on seemed to show cell terminal was hottest, cooked plastic around it and heat flowed out busbars and up stud to OSB sheet.

Fire!! Never cover LiFePO4 with wood!!!

New adventure.. I went inside the battery room. As the exhaust fans where working, and they are temp based, I felt OK to close the door. I used wood (MDF) to cover the cells and sit on top, and to prevent accident if something falls 2 left over pieces, 10mm, but strong enough to sit on, as...

diysolarforum.com

 

[ArthurEld]

The picture I focused on seemed to show cell terminal was hottest, cooked plastic around it and heat flowed out busbars and up stud to OSB sheet.

Fire!! Never cover LiFePO4 with wood!!!

New adventure.. I went inside the battery room. As the exhaust fans where working, and they are temp based, I felt OK to close the door. I used wood (MDF) to cover the cells and sit on top, and to prevent accident if something falls 2 left over pieces, 10mm, but strong enough to sit on, as...

diysolarforum.com

But the top of the cell looks protected from the busbar like the heat was coming from above.
This picture shows white next to the terminal that was covered by the busbar. If heat was coming from the terminal the terminal would be black and so would that white spot. The rid lines are where the busbar was.

 

[ArthurEld]

Probably the only thing that made flames was the plastic