Fire!! Never cover LiFePO4 with wood!!!

blutow

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really like those covers, nice work. This 3d design and printing is really impressive. How hard is it to learn for someone with basic computer (but no engineering) skills?
 

DThames

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No plans. Just measured them and drew up what I wanted. They are intended to prevent fire more than they are meant to supress or survive fire. It is PLA material (should burn well).
 

DThames

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really like those covers, nice work. This 3d design and printing is really impressive. How hard is it to learn for someone with basic computer (but no engineering) skills?
I would say fairly easy to learn. I have been around engineering all of my career but have never done mechanical design. There is a lot of help on the internet. I have a $200 printer and a free design program. I just start trying to make something and keep after it until it works. A set of calipers is most helpful.
 

ArthurEld

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No plans. Just measured them and drew up what I wanted. They are intended to prevent fire more than they are meant to supress or survive fire. It is PLA material (should burn well).
I was searching around and found fire resistant 3d printing materials but I have no idea how much it costs or if it is hard to work with.
I've been thinking about buying a 3D printer specifically for making terminal covers. I will probably find other things to do with it.
 

DThames

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I was searching around and found fire resistant 3d printing materials but I have no idea how much it costs or if it is hard to work with.
I've been thinking about buying a 3D printer specifically for making terminal covers. I will probably find other things to do with it.
I would not have expected such material for a typical low end 3D printer to exist.....heat and extrude type. Wow.
 

fhorst

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I would not have expected such material for a typical low end 3D printer to exist.....heat and extrude type. Wow.
It probably still will melt just the same :)
Just won't catch fire from external source (sparking wire)
Normal plastics will.

Eventually.. everything burns..even cement base...

Let's hope it never comes to that!!

I will have most likely the same approach of @Hedges, in my case cut a few parts of garden hose to cover the bare bars, just to prevent accidental short if something would fall in between.

In case of fire I now have Halon tank that will put it out at 68c temp.
 

ArthurEld

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It probably still will melt just the same :)
Just won't catch fire from external source (sparking wire)
Normal plastics will.
I am trying to stick to materials that won't feed the fire
Eventually.. everything burns..even cement base...

Let's hope it never comes to that!!

I will have most likely the same approach of @Hedges, in my case cut a few parts of garden hose to cover the bare bars, just to prevent accidental short if something would fall in between.
edit: These batteries are going to sit around for 10 years.
It isn't hard to imagine a piece of metal falling or bouncing on to the battery over all of that time.
I don't want to leave that possibility open.

Of course when I am working on the battery it is better to leave stuff covered as well.

One thing that bothers me about covering is heat dissipation. Bare copper must cool faster than covered copper.
How does that play into the equation?
In case of fire I now have Halon tank that will put it out at 68c temp.
The ultimate goal is to keep the roof from catching on fire. Hopefully we can each come up with a solution that does that.
 
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diyernh

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@ArthurEld , that's what I was worried about also.
It is the "heatsink" of the batteries.
Perhaps no garden hose...

What doesn't conduct electricity but does conduct heat??
I wouldn't worry too much about a buss bar covering thermally insulating the terminal Heat is harder to insulate. It takes sealing and thicker material.

I'm always into making things out of Obtainium. Anything household that could work? Silicone baking sheets? I like the car hose. Fiberglass from scrap parts?
 

Supervstech

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It probably still will melt just the same :)
Just won't catch fire from external source (sparking wire)
Normal plastics will.

Eventually.. everything burns..even cement base...

Let's hope it never comes to that!!

I will have most likely the same approach of @Hedges, in my case cut a few parts of garden hose to cover the bare bars, just to prevent accidental short if something would fall in between.

In case of fire I now have Halon tank that will put it out at 68c temp.
Where did you get Halon? I thought it was worldwide banned? CO2 tanks are plentiful and cheap.
 

ArthurEld

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I wouldn't worry too much about a buss bar covering thermally insulating the terminal Heat is harder to insulate. It takes sealing and thicker material.

I'm always into making things out of Obtainium. Anything household that could work? Silicone baking sheets? I like the car hose. Fiberglass from scrap parts?
Silicone is a great idea. Fiberglass would work.
But I was thinking a piece of Type X drywall would be cheap and easy.
Either just lay it on top or make the compression fixture higher to hold it up.
 
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fhorst

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Where did you get Halon? I thought it was worldwide banned? CO2 tanks are plentiful and cheap.
I need to correct: Halotron.
The environmental friendly alternative of halon 1211 as ceiling tank.
IMG_20210315_213233.jpg

IMG_20210327_215918_copy_1000x750.jpg

It was about $130,-

The room where it's used is small, 1.30*200, 225 high.
It's supposed to be enough for a room of 3*4 meter..

Fire won't stand a chance.

It does have to wait a few days as I'm working on my air in at floor level to work only as air suction, not escape holes for the Halotron :)
 

Ironman

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There are a lot of compounds that conduct and you would think not. How about rubber tires, yes they do conduct.
I found this on an MDF search: (https://www.tandfonline.com/doi/abs/10.1163/016942410X537189)
Since the powder coatings are preferably applied using electrostatic spraying equipment, sufficient electrical conductivity of the surface is a major requirement and the correct moisture content plays an important role as well. To this end, a new sophisticated procedure was developed to measure the electrical resistance (surface and core resistance) during pre-heating. The results show, that the electrical resistance of MDF is influenced by board temperature and moisture content. Moreover, it is confirmed that pre-heating proves to be an efficient method to improve the powder application onto non-conventional substrates.
 

fhorst

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Silicone is a great idea. Fiberglass would work.
But I was thinking a piece of Type X drywall would be cheap and easy.
Either just lay it on top or make the compression fixture higher to hold it up.
The type X would be a heavy lid :)
And a lid stops heat from escaping.
Holes would give ventilation, also location for fire to spread...

For me, the room has concrete fiber sheet against the MDF and plywood walls. It doesn't have to hold the fire back for a long time, just long enough to let the heat reach 68 degrees..

It might even be an idea to have "fire food" available that smokes like crazy, to trigger the smoke alarms more quickly.

Fire doesn't have to be a (really) bad thing. Not good, obviously.

As long as it's contained long enough and there is (automatic) equipment available to put it out..

We all know about prevention, and do it to the best of our abilities.
If there is a mishap, something goes terribly wrong.
Think about that.
And that you aren't there to put it out.
Will your setup still be there if you leave to the town for groceries?
-> and there is an accident like I had..

Prevention is good.
After the normal standard ways, it's (I think) better to prepare that there is a fire, and spend the money on that, instead of possible crazy expensive flame retardant alternatives. Most of us aren't building an airplane.

We have room for error, our house doesn't fall out it the sky.
There isn't a thermal meltdown (right term?) of LiFePO4 cells, but we do have many thousands of watts potential energy stored.

Am I wrong?
Accepting that prevention isn't all.
But prepare for the possibility that fire will occur and that I won't be there (on time) to put it out?

TV's used to be number one for creating fires for decades, I never thought about placing a halotron tank above it :)
 

Hedges

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What doesn't conduct electricity but does conduct heat??

For the most part, thermal and electrical conductivity go hand in hand, for instance copper cookware vs. brass or stainless. Something about the mobility of electrons serving to carry heat. There is one notable exception: diamond.

"Diamond has the highest hardness and thermal conductivity of any natural material"


All you need is a DIY PECVD system to coat your busbars.



Anybody else have a thermally insulating rubber case on your iPhone to protect it if dropped?
 
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