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Fire proof battery box?

Wycowboy

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Dec 30, 2020
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is it worth building a fire resistant battery box like out of cement board for my 48 v 16 s system?
 
Wondering the same myself. I was leaning towards something like this.

It could serve as security, an easily air conditioned space, and fire protection.

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What kind of batteries do you plan on putting in it. If it's AGM, FLA or LifePO4 it's probably not needed. This is very dependent on how comfortable you feel with where they will be located. If they are regular Lithium Ion cells, especially ones from an old EV or 18650 batteries I would most certainly put them in something fireproof and also not in my house.
 
I built a small cabinet out of plywood and lined it with concrete board. My cells LiPo4 cells, so it’s not really needed but it made me feel better. The cells also need protection from me and other people who may not be aware of keeping metal away from the bus bars.
 

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This is a new lifep04 battery I am building. The battery are in an small out building a way from the house. Iv seen a lot of folks just using a plastic tote but I was thinking of building something my self so was thinking cement board.
 
It’s no
This is a new lifep04 battery I am building. The battery are in an small out building a way from the house. Iv seen a lot of folks just using a plastic tote but I was thinking of building something my self so was thinking cement board.
It’s not a bad idea. I don’t know how handy you are but cement board doesn’t hold a screw. You can put screws through (or glue it) it to secure it to something else. You’ll need some type of frame to attach to. The battery should definitely be protected inside something. My attached garage sees a lot of traffic so that’s why I did what I did.
 
This is a new lifep04 battery I am building. The battery are in an small out building a way from the house. Iv seen a lot of folks just using a plastic tote but I was thinking of building something my self so was thinking cement board.
My electrical room is also away from the house. It's not just fires one has to worry about, it's also any venting of the batteries if something goes wrong.
 
I think it is worth building a fire resistant battery box out of cement board.
Custom made so it fits your space.

I built a small cabinet out of plywood and lined it with concrete board. My cells LiPo4 cells, so it’s not really needed but it made me feel better. The cells also need protection from me and other people who may not be aware of keeping metal away from the bus bars.
I like it. (y)
Now here come the questions.

Did you use a special paint to reduce the dust from the cement board?
Would you recommend Hardiebacker or some other brand?
Do you peek inside every now and then or have you considered a fiber optic option?
Have you considered placing a remote temperature sensor inside the box or an alarm?

That's it for now.
 
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I think it is worth building a fire resistant battery box out of cement board.
Custom made so it fits your space.


I like it. (y)
Now here come the questions.

Did you use a special paint to reduce the dust from the cement board?
Would you recommend Hardiebacker or some other brand?
Do you peek inside every now and then or have you considered a fiber optic option?
Have you considered placing a remote temperature sensor inside the box or an alarm?

That's it for now.
I used hardi board. The Durock brand is a true cement based board and likes to crumble. I thought about painting it but the dust is minimal unless your cutting it. I have a couple borescope cameras for work so if I did need to take a peek I would consider that. I do need to do some maintenance so I have to take my cover off for that. My Overkill BMS has temp sensors on it and I can read that through the blue tooth. The only other thing I did was to place a smoke detector above everything. I guess one inside the box is not a bad idea although the cells I have are allegedly not prone to fires like some other types of batteries.

I wouldn’t consider the box I built “fire-proof”. I would hope that it could buy some time to deal with a situation though.

When I was running the less stable pouch style packs I did have the idea to have the batteries in a box on wheels. I purchased an automotive style quick connect battery plug for it. If the batteries caught fire I would push or pull the battery cart out of the garage and when the batteries got about two feet from the wall the plug would automatically disconnect them as they swung into the driveway. Thankfully I just got newer cells but it’s a good idea if you could work out the details.
 
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a. I don’t know how handy you are but cement board
Thanks for the votes I’ll whip something up that’s fits my space working with cement board is no problem.
Would you recommend Hardiebacker or some other brand?
I would definitely recommend Hardy board 1/2 in or fiberrock avoid durarock. Smells terrible and is too flexible.
 
When I was running the less stable pouch style packs I did have the idea to have the batteries in a box on wheels. I purchased an automotive style quick connect battery plug for it. If the batteries caught fire I would push or pull the battery cart out of the garage and when the batteries got about two feet from the wall the plug would automatically disconnect them as they swung into the driveway. Thankfully I just got newer cells but it’s a good idea if you could work out the details.
This has to be the best Idea I have seen, and I have seen some really good ideas on this forum.

Nice one Darce. (y)(y)
 
Another option is ceiling tile. Regular Home Despot stuff. I researched it recently. Much of it is mineral board. Some is cellulose. Quick google search can tell you which is which.

Fireproof, light, cuts with a carpet knife. 98.7% sure it’s nonconducting. Did I mention light? Really light. Fragile though.

Cheap. Cheap. Cheap.

I put a mapp gas torch to it. Not gonna burn. Looked like a space shuttle tile. Tape the edges if you want to stiffen it up.
 
Another option is ceiling tile. Regular Home Despot stuff. I researched it recently. Much of it is mineral board. Some is cellulose. Quick google search can tell you which is which.

Fireproof, light, cuts with a carpet knife. 98.7% sure it’s nonconducting. Did I mention light? Really light. Fragile though.

Cheap. Cheap. Cheap.

I put a mapp gas torch to it. Not gonna burn. Looked like a space shuttle tile. Tape the edges if you want to stiffen it up.
Now were getting somewhere. (y)
 
Still think of building a insulated cement board box that will help keep them warm in winter. But will I then have to worry about over heating in summer.

How bad is it to skip the whole box idea as long as they are out of the way?
 
I would approach this from the system catching fire standpoint. Focusing on just the batteries may be myopic.

photo from


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How bad is it to skip the whole box idea as long as they are out of the way?
Not bad at all if you are using LFP batteries. There is little fire risk. Temperature control is important so insulation would ne needed if not in conditioned space.
 
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