Some thoughts on fire suppression for LiPo battery cells in RV

[KevinM]

I'm glad to see there is a discussion group about this topic, some interesting comments.

My main concern having a large battery bank in an RV is obviously the failure these batteries might have. Hot fires and RVs don't mix well.

In my plan the cells will occupy their own compartment secured on aluminum shelves we will fabricate. From everything i read, basic ABC type extingushers can put out the initial flames, but the thermal reaction in the subject cells will continue for a few seconds, possibly causing it or adjacent cells to reignite. So here's what i was thinking.

1) I can install a ABC "bomb type" automatic extinguisher, like the Protang which should take care of the initial fire.

2) In order to keep the batteries cool for a few seconds I can design and fabricate a small precharged water misting system (similar to that used in most commercial buildings, but just using mist not squirting water) with a gallon or two of water in a pressurized vessel. I can design the firing system using a pico or similar with flame sensors. The misting is just intended to keep the compartment and cells cool without creating any paths for additional shorts.

3) line the compartment with a high temperature material like what is used for light weight welding blankets, typically good up to 1800 degrees.

I get that ensuring the battery system is designed and maintained properly is the best way to prevent failures, but in the real world any number of things can go wrong and ruin your whole day.

Is this crazy? A little overkill? your thoughts?

 

[MisterSandals]

Really LiPo (lithium polymer)? The explode type in an RV would be out of the question for me.

 

[Rocketman]

LiFePO4 is the only ones for me - when I am sleeping. I have several of the 3.7v cells and I never leave them charging at night. Probably safe… but…

 

[Tomthumb62]

Are you confusing LiPo with LiFePO4?

Both lithium ion chemistries. One likes to explode and the other doesn’t do much other than smoke.

Unless you’re building your own LiPo battery, you won’t find these for sale for rv use.

 

[KevinM]

To clarify I'm referring to LiFePO4...from what I read these still can flame and have a thermal reaction

 

[Tomthumb62]

To clarify I'm referring to LiFePO4...from what I read these still can flame and have a thermal reaction

They can have a thermal reaction, but it’s not flaming. Often cool enough to touch. Bad smoke to breathe and best to leave asap and let it fizzle out.

 

[Rednecktek]

Just out of curiosity, since Lithium and Iron are metals, wouldn't you need a Class D extinguisher for them? Has anyone tried that yet?

 

[jberger]

I'm using a set of smoke detectors from XSense and metal cased batteries in ours.

I don't think there is much of a chance they will burst into flames, but the amount of energy they can discharge in a short or from frayed wires makes me think that a smoldering cable could the be the start of something.
I wanted metal cases on the batteries to limit the potential spread and the smoke detectors to give us a chance to get out before things got out of hand.

I think this is the right model from XSense, they are interconnected alarms and the wifi base station lets you monitor them from your phone.

FS31 Interconnected Smart Smoke Alarm Kit | X-Sense

Rest assured, you are protected and aware of your home's safety with the X-Sense Home Security app.

www.x-sense.com

They do offer a monitoring service, but since we are on the road, I self monitor from the phone instead.

 

[RandyP]

I'm using a set of smoke detectors from XSense and metal cased batteries in ours.

I don't think there is much of a chance they will burst into flames, but the amount of energy they can discharge in a short or from frayed wires makes me think that a smoldering cable could the be the start of something.
I wanted metal cases on the batteries to limit the potential spread and the smoke detectors to give us a chance to get out before things got out of hand.

I think this is the right model from XSense, they are interconnected alarms and the wifi base station lets you monitor them from your phone.

FS31 Interconnected Smart Smoke Alarm Kit | X-Sense

Rest assured, you are protected and aware of your home's safety with the X-Sense Home Security app.

www.x-sense.com

They do offer a monitoring service, but since we are on the road, I self monitor from the phone instead.

Can you give more info about your metal cased batteries ?

 

[jberger]

I'm using the EG4-LL 12V packs, nothing special I just wanted an external metal case not a rotomolded plastic one.

 

[sasquatch487]

I recently say a new firefighting tool for the home. They are "Fire Blankets" in a pouch with a spot to grab and a quick deployment with instructions on how to use. Looked amazingly efficient and certainly less mess than fire extinguishers. I have 3 different fire extinguishers in my van which I live in and the fire blanket is my next get .. ?

 

[maidstone53]

I ran across this product while researching fire suppression for my EG LifePower4 battery bank:

CellBlockEX Lithium-ion Fire Suppressant - CellBlock FCS

CellBlockEX is a dry granulate mineral-based material used for the prevention and suppression of lithium-ion battery fires.

cellblockfcs.com

 

[Lt.Dan]

I ran across this product while researching fire suppression for my EG LifePower4 battery bank:

CellBlockEX Lithium-ion Fire Suppressant - CellBlock FCS

CellBlockEX is a dry granulate mineral-based material used for the prevention and suppression of lithium-ion battery fires.

cellblockfcs.com

Looks very interesting

 

[42OhmsPA]

Looks very interesting

That cellblockex article mentioned vermiculite and I found this. https://www.avdfire.com/what-is-aqueous-vermiculite-dispersion/

Seems like it would be easy enough to make a vermiculite 'pillow' above a pack that would melt at high temps and smother everything, it would also be fairly easy to clean up.
?

 

[Skypower]

I had this fire suppression system in my boat’s engine room. It’s made by Fireboy Xintex. They are automatic with provision for manual activation. They have a normaly closed contact switch that opens on activation so this turns off the required indicator lamps (opens negative) at the helms and the shared negative for the engine room blower(off). This keeps the fire suppressant in place and not exhausted. The tank size is based on engine room size. Notes; Warning about opening the engine compartment and reigniting the fire AND not entering the space because of lack of oxygen. You don’t want this in your living space and be sure that harmful levels can’t get there(leak up while you’re asleep if triggered) I have it alarmed for sure. They are NOT inexpensive. You could install some fire and heat sensors in the compartment. One has both photo & ion. I’m very happy with these with no false alarms if you don’t count the one with me doing a lot of heat shrink in the vicinity. These have battery backup with 120VAC interconnect so you can rig it to a carbon monoxide fire detection combo in the cabin.

 

[TimE]

I'm glad to see there is a discussion group about this topic, some interesting comments.

My main concern having a large battery bank in an RV is obviously the failure these batteries might have. Hot fires and RVs don't mix well.

In my plan the cells will occupy their own compartment secured on aluminum shelves we will fabricate. From everything i read, basic ABC type extingushers can put out the initial flames, but the thermal reaction in the subject cells will continue for a few seconds, possibly causing it or adjacent cells to reignite. So here's what i was thinking.

1) I can install a ABC "bomb type" automatic extinguisher, like the Protang which should take care of the initial fire.

2) In order to keep the batteries cool for a few seconds I can design and fabricate a small precharged water misting system (similar to that used in most commercial buildings, but just using mist not squirting water) with a gallon or two of water in a pressurized vessel. I can design the firing system using a pico or similar with flame sensors. The misting is just intended to keep the compartment and cells cool without creating any paths for additional shorts.

3) line the compartment with a high temperature material like what is used for light weight welding blankets, typically good up to 1800 degrees.

I get that ensuring the battery system is designed and maintained properly is the best way to prevent failures, but in the real world any number of things can go wrong and ruin your whole day.

Is this crazy? A little overkill? your thoughts?

The best water mist systems used I data centres work under extreme pressure, circa 200 bar. The spray nozzles are sophisticated directional devices. I can't see how you would build anything close or work out how to active it. You certainly don't want an accidental activation.

 

[bds70]

To clarify I'm referring to LiFePO4...from what I read these still can flame and have a thermal reaction

From test videos I watched you have to seriously do some intentional puncturing damage to get lifepo4 to burn.

 

[Gusty4047]

Lifepo4 batteries have a BMS system that is supposed to protect the units. And most do just that. Make sure you buy good quality units. That said they are all made overseas and you hope they're good. They are sealed units and you cannot see what's inside. Some have had bad experiences with these babies. There are various inert gas extinguisher systems out there that function very well. Your local fire Department can really guide you to a solution ☺

 

[bds70]

Lifepo4 batteries have a BMS system that is supposed to protect the units. And most do just that. Make sure you buy good quality units. That said they are all made overseas and you hope they're good. They are sealed units and you cannot see what's inside. Some have had bad experiences with these babies. There are various inert gas extinguisher systems out there that function very well. Your local fire Department can really guide you to a solution ☺

The word "supposed" is accurate. BMS over current protection is not fast enough to cut off a dead short of the magnitude we are talking about, 20,000Amps is one hell of a bang. A fuse designed specifically for that scenario seems a more safe option to me.
This is a subject I have spent the last week in intense research and communications on here. See my thread "fuse between battery and cut off switch" There is a heap of info on their from folks here that know a ton load more than I do.

 

[AlarmProGuy]

There are a number of Lithium Iron Phosphate batteries that have fire suppression pucks inside the metal cases they reside in, Take. a look at the EG4 power pros, and there are a few others like it.

Cheers ..

 

[robbob2112]

In general if you do the math the current involved for a 12v battery is between 3000 and 5000amps - BUT - as Will proved on his latest video - those with overcurrent protection will generally cut it off if the right size wire is used.

If you undersize the wire so there is more resistance and it limits the current flow a but it will get red hot without triping the overcurrent protection. This also goes for long length between the batteries and invert/bus bar/scc/etc.

Not all batteries have that feature if you get to the bottom end of things where the better of the bargin batteries do as well as most of the high end.

Net result - High MRBF fuse is the way to go - My rule of thumb -

Single 12.8v battery - MRBF on post
Two 12.8v batteries in parallel - MRBF on post of both batteries
Three or more 12.8v batteries in parallel - class T on each - can be the midget form factor (hard to find) or the regular bolt down.
two (or more) 12.8v in series - class T between the positive post and bus bar - jury is out on MRBF on each post as well - I don't series batteries
24v or higher - class T on each battery no matter how hooked up.

On batteries -
ANL, ANN, Mega, other fuses that originate in the automotive/car audio world - don't use them - to low AIC, usually a lot of waste heat from internal resistance, and they don't contain the short very well typically.
On distribution panels like a car/boat/RV fuse box - I might use them up to 80amps or so, but in reality I would probably use a MRBF to connect that