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Lithium iron phosphate battery safety (LFP)

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x98myers7

Solar Enthusiast
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My father and I continue to be at odds regarding lifepo4 safety. he is insistent that it is inherently unsafe citing all the tesla fires/failures and inability to contain/stop runaway combustion, as well as insurance companies failing to issue payouts to owners and requiring them to park EVs outside of their dwelling. TSA flight restrictions for batteries, etc.

obviously, I am not talking about LTO, or li-po chemistries... only LFP.

so, given the dozens of videos on Youtube disproving it....
(geez... just do the search for yourself)

but... i have to be honest, I still have that nagging "concern" in the back of my head. I have two CHINS 24v 100ah LFP packs powering my system. they're in the basement well-pump room, properly connected to a 2kw array and very modest loads. no external ignition sources nearby. the concerns come with the highly combustible hydrogen produced during the reaction, which is HIGHLY flammable.

the concern comes with stuff like this...

would it be silly overkill to build a sheetrock/drywall cover vented to the exterior of my house with steel conduit?
 
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LFP does not off0gas and if it did, it is not hydrogen which is what Lead Acid batteries vent when charging. LFP, LYFP & LMFP are presently the safest chemistries in use. Ol & Gas interests and their Mediaganda hordes love to make mountains out of nothing just to keep the status quo...

Drywall is pointless. Some folks build a "Battery Closet" using cement fireboard which is expensive, difficult to work with and honestly NOT that good. Better & cheaper product that handles up to 3500 degrees and is hydrophobic is Magnesium Oxide (Mag-O) sheets.

HINT for Credibility & sanity check:
- In 2021, there were around 174,000 highway vehicle fires reported in the United States.
- From 2010 to June 2023, EV FireSafe recorded 393 verified passenger EV battery fires across the world, of which only four were in Australia.
MediaGanda sure spins it up like crazy... Like that Car Carrier that caught fire, immediately blamed EV's but when investigating ALL of the EV's were driven off the ship, the fire happened 3 levels up and caused by a diesel pusher... BUT MediaGanda didn't care about facts.

BTW: I'm in Northern Canada, my powerhouse (50' from house) has all of my solar gear as well as my well & pressure tank, heated to 15C/59F. I am remote, rural and 100% offgrid (grid is 1km & 75 Grand away) and staying put.
 
Mine are inside the house, and I don't worry about them, but I have thought about building a separate power house for my system just to minimise the questions.
 
Steve_S said:
LFP does not off0gas and if it did, it is not hydrogen which is what Lead Acid batteries vent when charging. LFP, LYFP & LMFP are presently the safest chemistries in use. Ol & Gas interests and their Mediaganda hordes love to make mountains out of nothing just to keep the status quo...
Click to expand...

Great to see you on here, Steve. I hope you're doing well.

When i say "off gas", I'm referring to the gas byproduct of a mechanical puncture or physical damage to the cells obviously not charge/discharge due to normal use.

basically, i'm wanting some 'insurance' should I have a runaway overcharge scenario that results in cells swelling and then case failure... perhaps due to both an SCC and BMS failure. I realize i'm stretching, but am overly cautious.
 
Steve_S said:
BTW: I'm in Northern Canada, my powerhouse (50' from house) has all of my solar gear as well as my well & pressure tank, heated to 15C/59F. I am remote, rural and 100% offgrid (grid is 1km & 75 Grand away) and staying put.
Click to expand...

how are you heating it?
 
It took me 2 years to put my LFP batteries into service because I was afraid to use them under my roof.
I was using AGM batteries in my attached garage.
I finally got a detached shed and set up my DIY LFP batteries in there.
 
I'm venting my DIY battery to the outdoors via 4" of 4" dryer duct.

The longer or skinnier the vent pipe the better the box would have to be sealed to get the gases to exit that way.
 
I am also worried. I have 20kwh Pytes V5 in closed loop communication 15 feet from my Solark 15k (4/0 cable x 2). Three feet away from the batteries is my natural gas boiler! I do have the Pytes V5 in a metal server rack.

Not sure what more to do to protect this. I lowered the charge rate from the grid to 60 amps. I have a smoke alarm and I just bought a CO2 fire extinguisher 15 lb, but I am sure that would be pointless if the batteries catch fire.
 
okay, so I guess i'm not crazy. thanks for validating that. I'm also seriously considering adding another battery considering how far lifep04 battery prices have dropped.

I think you all have convinced me to construct a concrete 'box' to put all them with a steel vent tube outside.

1/2 USG cement board is https://www.astm.org/e0136-22.html compliant, so 1200deg.

based on this, should be able to pretty easily get a 1 or 2hr combustibility rating -- https://www.buildsite.com/pdf/usg/USG-DUROCK-Brand-Cement-Board-Systems-Technical-Notes-B26750.pdf

considering lifepo4 reacts at under 400degF, should be a reasonable approach to containing the offgasses until the energy is expelled
 
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If you want to do this project correctly and achieve your goal, I’d vent the compartment like a lead acid battery. That is, top and bottom. Otherwise, it will not vent hydrogen. The methods for venting lead acid battery compartments are well established.
 
Biggest difference for LiFePO4 seems to be that it vents below auto-ignition temperature. Requires separate spark to ignite, unlike some chemistries that "vent with fire".

The Tesla models presently in the US are of a more hazardous chemistry, but Tesla went to great effort to reduce the risk.

Fire risk should be greatly reduced using LiFePO4.

Maybe it is OK to build a "fireplace" sealed from the dwelling and vented to the outside.
But I think it would be safest to locate them in a climate-controlled "ammo dump" away from the dwelling.
 
Used sheetrock to line the inside of the battery boxes. Not necessarily to stop a fire, but to buy time to react.
 
The Teslas were not LiFePO4 (Lithium Iron Phosphate) but rather LiNMC (Lithium Nickel Manganese Cobalt) a HUGE difference. LiNMC has the potential for thermal runaway and ignition whereas LiFePO4 on its own does not.

You don't have to vent LiFePO4 or LiNMC because they do not create hydrogen gas when charging.

If you have any tool batteries in your house those are LiNMC, technically they are far more dangerous than a bank of LiFePO4. Despite that I have 10kwh of tool batteries all throughout the house and 48 kwh of LiFePO4 sitting in the basement. Some of my tool batteries are 9 years old. I've never seen one get hot or start a fire. I do avoid using rapid chargers for the health of the tool batteries and charge with my own DC to DC chargers to 4.1V
 
SupraSPL said:
You don't have to vent LiFePO4 or LiNMC because they do not create hydrogen gas when charging.
Click to expand...
i'm well aware. the point of it is to contain the reaction and block any possibility of ignition by an external source should there be a mechanical failure or overcharge/damage cells/etc
 
Boy, if even LiFePO4 batteries are this dangerous it looks like my Nitroglycerin batteries are not something I should keep under my bed.

I do have mounted a fire extinguisher, smoke detector, C0 detector and fire suppressing blanket next my indoor LiFePO4 banks. Pretty well satisfies me for safety. I would never do that with lead acid batteries though. Those I would want a separate vented outdoor setup.
 
How about an automatic fire suppression system in the battery box?

Anyone know a good one? Like everything else price varies ?
 
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