Best material to insulate batteries? Best R-value?

[justinm001]

Really interesting chart. Especially the new/used 5-10 years value for some material.
Sad they don't include the poor value of the Polyiso when temperature drop.

View attachment 181412

My problem is these all are only using conventional insulation methods that require the ability to breath and other factors needed for moisture control.

 

[Tomthumb62]

Rock wool is made from slag of steel production. It catches fire at several thousand degrees (very safe)
Mineral wool is similar but can be made from molten spun rock, slag from steel production, or any other minerals
both virtually cannot catch fire.. If that's any worry of yours. You should use one of those. They're available all over. You can put a blow torch on them and nothing will happen to confirm.

Cellulose also has very heavy soaking process of flame retardant. It's the second most flame resistant but also probably terrible to work with to do around batteries.

Pink foam board is the best foam board and also is "fire retardant" it'll still melt though, as will every foam except thermal spray/treated foam but that's the treatment spray protecting it. Also resistant to most weather and molds etc. It's used in pool/hot tub more than others

Fiberglass just melts

If you want spray foam to just "fill everything" like you say, you can get

FROTH-PAK Low GWP 620 Spray Foam Sealant Kit 12031908 - The Home Depot

FROTH-PAK Spray Foam Sealant is a 2-component, quick-cure polyurethane foam that fills penetrations and cracks in rim joists, roof wall junctures and around pipes and ducts greater than 2 in. and less

www.homedepot.com

or

FROTH-PAK Low GWP 650 Spray Foam Sealant Insulation Kit 12031907 - The Home Depot

FROTH-PAK Spray Foam Insulation is a Class A Fire Rated 2-component, quick-cure polyurethane foam that fills cavities, penetrations and cracks in rim joists, roof wall junctures and around pipes and ducts

www.homedepot.com

red one is more but it has some more ratings on it, including fire retardant etc

-----------------------------------

If you want a giant pack of something you can get https://www.lowes.com/pd/ROCKWOOL-C...th-Sound-Barrier-15-25-in-W-x-47-in-L/3610406 which will give you half your R value you're after.

Or just use a few pink foam boards (only home depot carries them) https://www.homedepot.com/p/Owens-C...Foam-Board-Insulation-Sheathing-45W/100320352
cost adds up but there you can easily see it'd be 10 inches thick to get your R50 (since the boards are 2 inches R10)
This product is extremely easy to cut and you can use a variety of tools but the easiest is a very small toothed saw like a japanese style pull saw or a hacksaw just with the blade. Sawzaw makes a huge mess and hot knife stinks and also shrinks the product

Personally for your R50 I'd do a concrete board structure for the internal space to get the size right. Wrap it with rock wool and then make the outside look nice with whatever.. wood etc.


I've already done this and you only need like 20 watts of power and <R10 so if you're actually wanting to do R50 you probably don't need heating at all

Reptile Heating Pad To Keep LFP Batteries Warm?

There has been a few discussions on self heating LFP or using external heaters and it occurred to me I used to have an iguana and used a small pad heater in the tank that actually got very warm and used low watts. So I looked for them on Amazon and they have lots of models big and small and...

diysolarforum.com

If it's windy against your battery you want a wind barrier on the outside of the insulation or it'll pierce through it and cool faster... literally anything. Plastic, wood, concrete board etc. Sounds like your batteries might be outside idk



Aerogel also should be non-flammable until thousands of degrees.. but it probably has an insane cost lol
but yea I think that'd win, I don't think anything is more insulative than aerogels are (that we've discovered yet)

FYI, if anyone is considering using rock or mineral wool and think it’s a “green” insulation, think again. The processing of it is extremely toxic and rarely had any environmental restrictions (or enforcement) to help protect people and the environment.

I agree it’s an amazing insulator and virtually non flammable, but if you care about the environment and your health, try other options first.

While fiberglass will melt at high enough temperatures, it won’t catch fire. We used to use it in “cat can stoves” we used for camping, the fuel source was anything from kerosene to denatured alcohol.

 

[gotbeans]

The first time I checked on my system in my RV after a heavy snow storm left about 10" of snow on the panels, I was very surprised at how little the state of charge dropped to keep the batteries warm without getting anything from solar. I checked about five days after the snow storm.

snow is very good insulation too. heavy wind / rain cools stuff down the most..
...until the weight of the snow caves in someones roof.. then it gets real cold

FYI, if anyone is considering using rock or mineral wool and think it’s a “green” insulation, think again. The processing of it is extremely toxic and rarely had any environmental restrictions (or enforcement) to help protect people and the environment.

I agree it’s an amazing insulator and virtually non flammable, but if you care about the environment and your health, try other options first.

While fiberglass will melt at high enough temperatures, it won’t catch fire. We used to use it in “cat can stoves” we used for camping, the fuel source was anything from kerosene to denatured alcohol.

Yea it's like a lot of recycling processes, at least they're using the left over slag from steel but most of reuse/recycle is pretty dirty process.
fiberglass melts at pretty low temps, any ordinary flame will do it. A surprising amount of the foams are the same, way more than I thought. Most of them don't actually catch fire but just melt and release black smoke.

My idea with the rockwool is, if a battery catches fire it isn't going to leave my box

 

[Tomthumb62]

fiberglass melts at pretty low temps, any ordinary flame will do it.

In my camp stove, it never melted, or least not much. Granted, denatured alcohol is pretty low BTU so it never got all that hot in there, but google says 1100C for denatured alcohol and 1700C for a regular candle flame. So perhaps this isn't exactly an "ordinary flame", lol.

 

[gotbeans]

In my camp stove, it never melted, or least not much. Granted, denatured alcohol is pretty low BTU so it never got all that hot in there, but google says 1100C for denatured alcohol and 1700C for a regular candle flame. So perhaps this isn't exactly an "ordinary flame", lol.

damn that's crazy how much lower the alcohol is

There are several levels of fiberglass too but this is the test I go by most of the time
a torch like that should be 1100-1300C so pretty close to denatured alcohol, but it's also directly on it and piercing into it and not just "next to it"..
I don't think it'd melt if it's just sitting near the flame

can't find lifepo4 specifically but:
The burning lithium creates a metal fire existing at temperatures of 2,000 degrees Celsius/3632 degrees Fahrenheit

 

[Tomthumb62]

damn that's crazy how much lower the alcohol is

There are several levels of fiberglass too but this is the test I go by most of the time
a torch like that should be 1100-1300C so pretty close to denatured alcohol, but it's also directly on it and piercing into it and not just "next to it"..
I don't think it'd melt if it's just sitting near the flame

can't find lifepo4 specifically but:
The burning lithium creates a metal fire existing at temperatures of 2,000 degrees Celsius/3632 degrees Fahrenheit

That's all really interesting!

For the record, the flame in a 'cat can stove' goes through the fiberglass:

Take a clean, empty can of cat food.
Punch some holes near the top with a pointed can opener.
Fill can with regular fiberglass (I used some leftover from housing construction, sans paper).
Pour 1 oz of denatured alcohol into the fiberglass and light it on fire.
Place under a pot-stand and put your pot of water on the stand, with the flame not too close or far.

As far as burning lithium, I was under the impression that LiFePO4 does not reach high temperatures. It simply "smolders" and is cool enough to touch when it's "on fire". Other lithium chemistries, however, can and do catch fire and reach high temperatures.

But regardless of science, I understand that people can get nervous about having a 50-100kWh (or even smaller) of LiFePO4 battery in their house.

It's like when I wear a good tight-fitting N95 mask and stand 6+ feet away from someone and tell them I have covid while outside with the wind at their back, they back away from me. There is pretty very very very little chance of a meaningful amount of the virus escaping my mask and then going against the breeze to infect them. It's not rational at all and people will respond to their feelings instead. Feelings of fear in both the case of covid and smoldering LiFePO4 batteries. Can't say I wouldn't react the same, but I will have to remind myself that it goes against the data.

 

[gotbeans]

ah I looked one up and see it. It didn't even shrink the fiberglass at all?

From the video (unfortunately he starts fiberglass kind of cut off from the video) but you can tell he was burning it a while before that and it wasn't moving much at all

I've seen lifepo4 fires and they're decent fires like

at 3:15
but yea definitely not like some of the li-ion ones

I think even for sodium ion I'd have rockwool because it's basically the same price anyway and much better to not have house burn down cuz of something so simple.. rather it be a complex thing like some wire ran 40 years ago that got hot
If the rockwool was like 10 times the price of any other insulation I'd probably just rely on the concrete board though since as you said, the data shows lifepo4 not gonna melt through that

also battery fires are almost entirely dependent on the amount they're currently charged at. So a lot of videos don't really tell you whether it's topped off or not =[

 

[Tomthumb62]

ah I looked one up and see it. It didn't even shrink the fiberglass at all?

From the video (unfortunately he starts fiberglass kind of cut off from the video) but you can tell he was burning it a while before that and it wasn't moving much at all

I've seen lifepo4 fires and they're decent fires like

at 3:15
but yea definitely not like some of the li-ion ones

I think even for sodium ion I'd have rockwool because it's basically the same price anyway and much better to not have house burn down cuz of something so simple.. rather it be a complex thing like some wire ran 40 years ago that got hot
If the rockwool was like 10 times the price of any other insulation I'd probably just rely on the concrete board though since as you said, the data shows lifepo4 not gonna melt through that

also battery fires are almost entirely dependent on the amount they're currently charged at. So a lot of videos don't really tell you whether it's topped off or not =[

Oh wow, that's different! And at the hands of our own @HighTechLab , too! Nice to put a face to the user name after all these years!

So lesson here is: don't let your lifepo4 get punctured more than once, lol.

 

[gotbeans]

oh lol didn't even know that was someone here but I guess that makes sense, most of the youtubers for this probably made an account here too.
Yea there are some other videos that show lifepo4 as basically "extremely safe" I wonder their charge state of batteries.. If I test stuff I max the charging to absolute max and then hit it..
but yea hopefully nobody drives a steel bar into my battery case ?

you never know what can happen though over the years of the chemistry inside, and I really don't want a fire on my actual structure
I use foam board all over my shop which is metal but inside I only use rockwool / treated cellulose

 

[Bluedog225]

Fwiw-acoustic ceiling tile are often mineral board. Light, fire proof in practical use, and cheap.

 

[gotbeans]

Looks like they get some distortion when heated (since they're so light/fluffy?)
also fall apart when working with them
at least in the states these insulation all pretty much the same price. Foam is where the price jumps, especially spray foam

 

[rcrracer]

Aspen Aerogel. Seems to be an Aerogel in name only. R-10 per inch thick. Typically 6mm thick so four layers needed for an inch. Expensive. Different types and temp. ratings. This guy in VA Beach has been selling it for years: https://www.ebay.com/str/surplusmeisters/Insulation/_i.html?_sacat=63894 It's also for sale on Amazon(may be the same VA Beach guy.)
Polyiso(R-7? per inch) on Search Tempest.

 

[rhino]

FYI, if anyone is considering using rock or mineral wool and think it’s a “green” insulation, think again. The processing of it is extremely toxic and rarely had any environmental restrictions (or enforcement) to help protect people and the environment.

What exactly of the processing of it is extremely toxic? As far as the end product that you have in your home, foam is extremely toxic in a fire since it produces deadly smoke whereas rock wool would not.

 

[gotbeans]

Aspen Aerogel. Seems to be an Aerogel in name only. R-10 per inch thick. Typically 6mm thick so four layers needed for an inch. Expensive. Different types and temp. ratings. This guy in VA Beach has been selling it for years: https://www.ebay.com/str/surplusmeisters/Insulation/_i.html?_sacat=63894 It's also for sale on Amazon(may be the same VA Beach guy.)
Polyiso(R-7? per inch) on Search Tempest.

damn they don't even do graphene aerogel... theirs is plastic and fiberglass based different types of them
I was wondering why R10 at 1 inch (~2.5cm) I think graphene is like double that lol also fireproof
probably 50 times the price