Battery bank Cabinet/enclosure in case of fire

[glamsland]

I'v been running my nmc ev batteries for some years now. All good, no problems.

Its total of 12 KW , 24v setup. 2 battery banks in paralell. " 2 Jk-bms..

Charging from 22v(3.14v/cell) to 28.4(4.05v/cell)

It in a off grid cabin in the woods, far from roads and any other cabins or people.. THe batteries are mounted in a Firewood shed 10meters from the main cabin.

My big fear is IF the batteies goes wild, and for some strange reason catch fire.. Its going to be a big fire!
I don't worry about the shed, but more with Forrest fire. THat will be realy bad.

Soo. . What do you think? Will a steel cabinet keep a lithium ion fire under control? Or will it be better to use something like concrete blocks to make a box around the battery box?

I guess it will burn for hours, so it need to stand up for some heat ..

 

[wpns]

Look for threads here on lithium ion fires. I know it's a lot of money, but can you convert to LFP with commercial ratings and built-in fire extinguishers?

 

[BarracudaBob]

Get a large grapple

 

[justgary]

I don't worry about the shed, but more with Forrest fire.

You don't say where you are, but if you are concerned with forest fires you could consider performing occasional prescribed burns to reduce the amount of fuel available in a controlled way.

 

[robbob2112]

There are multiple threads on fireproof buildings...

IMO a cinderblock building with the walls lined with rock wool and fireboard, separate battery room from inverter and equipment. Insulate all and do vents controlled to use waste heat to warm the battery room.

Thermal monitoring to turn fans off and on. Hydrogen detection to turn on battery room vent fan (ignition safe)

 

[Sparks-n-Splinters]

I've been considering this very thing as I'm still in the planning stages of my off grid system with miles of national forest only a stones throw from my place. A concrete block building with a metal roof solely dedicated as a power shed is where I have landed. still giving thoughts to a fire suppression system inside but have not finished my research yet on those.

 

[robbob2112]

There are fire suppression systems for LFP - but expensive - It interfers with the burning. Fire departments put out LFP battery fires with a slurry of sodium cloride and a few other things to make it a bit foamy. When it dries it can just be swept up using basic PPE.

When LFP batteries vent 50% ish of the gas is hydrogen. The rest is stuff you don't want to breath. So long as there isn't a spark or anything over around 300c the vent ends and the gasses dispurse. If the temp is over that the electrolyte breaks down and produces oxygen and a few other nasty things. Now you have the makings of a good fire.

Simple solution is to have the batteries in a sealed space with a hydrogen detector and a fan or other fire suppression measures - a fan to clear the closed room of hydrogen, a fire extenguisher to blow, a nitrogen or halon bottle to fill the room... The fan and extenguisher are the only things you can do in a space that might have a human in it.

I would tie the hydrogen detector in with temp sensors seeded around the room and start the fan anytime it is detected, but only blow the extenguisher if there is sharp rise in one or more temp sensors.

 

[50ShadesOfDirt]

You have NMC (ev car) batteries, so I'd look for techniques specific to those from whatever car manufacturer produced or still produces them. This will give you background info on fire suppression for that battery tech.

I don't know who provides your area fire protection ... a VFD, or a City fire department? I'm guessing a VFD ...

For LiFePO4, it still seems that drowning these kinds of battery fires are most rural fire departments' procedures. Some might be progressive enough (they have the money) to have some special extinguishers and solutions, but I'd think the majority of VFD's would still be at the "throw lots of water at it" stage. At our VFD, we have no special extinguishers ...

Otherwise, I'd mitigate all around that storage shed, as most likely the whole thing will go up ... while a battery box will help, if the whole pile of batteries ignite, one after the other, the shed will most likely ignite and burn. By clearing (reducing wood & fuels 50' or so) all around it, you'll help the firefighters with time to get there and keep protecting everything else.

Hope this helps ...

 

[J.H.]

Keep it all outside 20 ft away … prob solved.

 

[kimmer6]

In August 2024, a BMS must have failed and set fire to my battery bank in my shop. The system was 24 volts, 3600 Amp Hours, had a 6KW inverter charger and a pair of 3KW high frequency inverters. At the time of the fire, the total load on everything was under 750 watts, battery was at 3599AH, both 60 amp MPPT's were outputting only 1.5 amps. There was NO REASON for this battery to catch fire. The system operated flawlessly 24/7 for 2+ years. The fire burned up my 50 amp garage sub panel on the wall behind the unit. The power console was not connected to the house at all. It ran freezers, refrigerators, and sometimes a window AC unit by extension cords. The receptacle outlet on the unit was protected by breakers hidden under the yellow tape. I heard the loud pop, saw black smoke, called 911 and charged my roof deck fire hose. I had water blasting through the skylight within 70 seconds. The column of black smoke burnt my arm but started to cool off and the smoke turned gray. The insurance company estimated the damage at $150,000. It's mostly smoke and water damage.

I will buy and install an 18Kpv EG4 unit with 3 outside rated batteries. It will go in a concrete shed far away from the house or shop. I was not supposed to be home when the fire happened. The Fire Investigator said that the whole house would have been lost had the fire penetrated the ceiling and my bedroom floor. I DO NOT TRUST LiFeP04 batteries any more after this event.

I home built 14 LFP power units since 2017 in many sizes for friends, family, and myself including motorhome and camper van use. Everything in this unit was fused, cables were oversized, all ends hydraulically crimped, no shortcuts, big copper bus bars, etc. This should not have happened. I always feared wildfires coming up this street so I added hose cabinets and a sprinkler system around the house. A garden hose would not have cut it.

 

[BarracudaBob]

I am glad you were home and able to put it out so quickly.

 

[robbob2112]

Yikes - Those pictures deserve their own thread in "Up In Smoke" -- then you can post pictures before/after and all the details. We could learn something possibly avoid it.

 

[Brucey]

In August 2024, a BMS must have failed and set fire to my battery bank in my shop. The system was 24 volts, 3600 Amp Hours, had a 6KW inverter charger and a pair of 3KW high frequency inverters. At the time of the fire, the total load on everything was under 750 watts, battery was at 3599AH, both 60 amp MPPT's were outputting only 1.5 amps. There was NO REASON for this battery to catch fire. The system operated flawlessly 24/7 for 2+ years. The fire burned up my 50 amp garage sub panel on the wall behind the unit. The power console was not connected to the house at all. It ran freezers, refrigerators, and sometimes a window AC unit by extension cords. The receptacle outlet on the unit was protected by breakers hidden under the yellow tape. I heard the loud pop, saw black smoke, called 911 and charged my roof deck fire hose. I had water blasting through the skylight within 70 seconds. The column of black smoke burnt my arm but started to cool off and the smoke turned gray. The insurance company estimated the damage at $150,000. It's mostly smoke and water damage.

I will buy and install an 18Kpv EG4 unit with 3 outside rated batteries. It will go in a concrete shed far away from the house or shop. I was not supposed to be home when the fire happened. The Fire Investigator said that the whole house would have been lost had the fire penetrated the ceiling and my bedroom floor. I DO NOT TRUST LiFeP04 batteries any more after this event.

I home built 14 LFP power units since 2017 in many sizes for friends, family, and myself including motorhome and camper van use. Everything in this unit was fused, cables were oversized, all ends hydraulically crimped, no shortcuts, big copper bus bars, etc. This should not have happened. I always feared wildfires coming up this street so I added hose cabinets and a sprinkler system around the house. A garden hose would not have cut it.

Glad you are ok. We've seen wooden battery shelving units have issues in the past where things start pancaking and collapsing when things get hot.

Those look like commercial batteries? Can you give us details so we can avoid them?

 

[robbob2112]

End on they look like Chins or LiTime or Ampertime - the orange cover ... You can see the side in one picture - they are Chins.

Looks like 3 rows - 12v - 400ah - series to either 24 or 48v.

or



Please do open a up in smoke thread for us all to learn.

 

[x98myers7]

bumping this up. I've been debating it... but you convinced me. I am in the process of decomissioning my chins batteries. they'll go in our motorhome, instead.