Battery Fire Protection ideas

[cbk]

I've ended up installing my Inverter and batteries in a plant room created in the loft space.  This is an insulated space and also includes the MVHR.  Batteries are Pylon US5000 and I currently have two but hope to add a further two in the future.    I plan to line the walls and roof with fire proof plasterboard and the access door will be FD30.  If a fire was to occur this should contain things and the room has a smoke detector fitted,  but as the MVHR is in the same space and ductwork is plastic this could easily cause smoke etc. to spread throughopuit the house.  Should I aim to enclose the inverter and battery setup  somehow to reduce the risk of fire spread?  Or would this increase the risk of overheating and create more problems than it solves?  Or is it a better optiopn to enclose the MVHR and keep it seperated from the Batteries?

Any advice much appreciated.

[JohnMo]

I think if a fire does start in these batteries it is very hard to suppress. Not sure if it's the same tech as car batteries, but cars gets put in a skip of water for 12+ hours.

 

So if it did happen you possibly have more to worry about. Most likely it would trip the RCD anyway and that would kill the MVHR.

 

Also in most domestic situations you faff about not believing it's a fire, so some smoke and all the alarms going off would prompt you to get and family out of the house.

[markc]

Lithium battery fires are fierce! And produce a lot of smoke and fumes, halon, co2 or similar fire suppression systems have little to no effect as the fire is a reaction rather than combustion. Personally I wouldn’t have any large lithium batteries in a loft but if it was necessary they would be in a large fireproof (hardybacker etc) crate with the top vented/chimney to atmosphere.

[billt]

Depends on the battery chemistry. If they are LiFePO4 they are pretty safe, it's very hard to ignite them and they don't support combustion in the way that other chemistries do.

 

I would never put batteries of whatever type in the loft. The temperatures are likely to be extreme which isn't good for the batteries, they're not very accessible and there are other fire risks apart from the chemistry. They store a lot of energy and an electrical fault can cause a fire.

 

Mine are outside, I don't want 70kWh of energy storage in the house.

[Kelvin]

I wouldn’t have them in the house let alone the loft. I’ve even decided to not fit PV panels to the roof for a variety of reasons one of which is the (low) fire risk. I know of two house fires caused by faulty PV installations. We’re also installing our EV charging point stand alone and away from the house to make sure we never park the leccy car near the house. 
 

Can you not construct a metal shed to mount it all in? 
 

 

[DougMLancs]

Pylontech’s are LiFePO4 so as @billtsays, a lot less hazardous than the LMNC battery chemistry found in YouTube video clips, Powerwall batteries and more widely elsewhere. I believe it’s the cobalt that produces the self-sustaining reaction. 

[PhilT]

The only place my battery can go is in my extension loft, which raises a fire risk question, and that space gets pretty hot in the summer. For these reasons I went for an LiFePO4 battery. There are a number of references online talking about the inherent safety and stability of LiFePO4 - the fact that it is incombustible, has a safe operating temperature range of -20 to +60degC and longer life expectancy due to the chemistry's stability during charge/discharge cycles.

Edited June 22, 2023 by PhilT

[cbk]

Thanks for feedback guys.  Good to know I've got the  LiFePO4 type batteries which seem much safer.  Additionally my loft space is a fully insulated warm roof so wont suffer extremes of temperature.  But just to be safe I still plan to line roof with fireproof plasterboard or would it be better to use the HardieBacker fireprrof board which would save the need to plaster  skim the board.

 

 

[PhilT]

3 hours ago, cbk said:

just to be safe I still plan to line roof with fireproof plasterboard

What about the floor? That's where all the flaming debris will fall.

[cbk]

Ah good point.  Will add Hardie backer on the floor as well. 

[Alan Ambrose]

There are some automatic fire extinguishers which might be worth investigating too.

[Post and beam]

Fire extinguishers probably would not put out a battery fire.

I would never have Batteries in my house and especially not in the loft.  When i used to fly large drones i kept the batteries in ammo box's that i bought on Ebay.

The only thing that i have seen that has a chance of at least smothering A LiPO battery fire is a large quantity of sand. 

Picture this. Battery is stored/charged in a bucket with a plastic sheet suspended above filled with sand. A fire melts the plastic sheet and the falling sand smothers the fire.

No i know its not practical in this situation which is why i said i wont have them in the house.

 

A friend with a new PV install has his battery outside bolted to the wall. is this not an option?