Batteries in plant room and 120 minute fire rated walls

[Dillsue]

1 hour ago, saveasteading said:

My hunch is to use low risk batteries, with an inherent suppression if possible, and to keep it an an enclosure (small room or cupboard)  that is 120 minutes construction, incl the door.

Vent to outdoors to remove heat?? Include a fire alarm.

That's likely to ammount to more than just a "few £" for what was shown to be a very low risk upthread. Would you do that for a tumble dryer or any other appliance, or a garaged ICE car all of which seem to pose a greater fire risk than a modern battery pack??

[saveasteading]

36 minutes ago, Dillsue said:

Would you do that for a tumble dryer or any other appliance,

No. It is the battery thing! 

A car in a detached garage is low risk to the house, but if there's a room above then that sounds scary... though

 the door should fail first and vent it.

38 minutes ago, Dillsue said:

likely to amount to more than just a "few £" 

I will report back. I'm thinking an extra layer of plasterboard and intumescent strips on the door. 

It appears that battery type is the most important thing.

[Dillsue]

36 minutes ago, saveasteading said:

No. It is the battery thing! 

If you read the report that @DamonHD posted, and other sources, household batteries should be pretty near the bottom of the list of domestic risks to worry about and spend £££s mitigating.

[SteamyTea]

9 hours ago, Dillsue said:

If you read the report that @DamonHD posted, and other sources, household batteries should be pretty near the bottom of the list of domestic risks to worry about and spend £££s mitigating.

They are, but the consequences are high, similar to a car fir.

A tumble dryer, generally, is lower consequences i.e. less energy to burn, less spread of flame as they should be vented to outside properly.

Then there is the way of extinguishing problem. 20 kWh of batteries may take a few hours.

So the risk may be low, but the consequences are high.

 

Risk management is all about the balance.

[Nickfromwales]

3 hours ago, SteamyTea said:

Then there is the way of extinguishing problem.

And here's where the fabric won't be saved. 

 

3 hours ago, SteamyTea said:

20 kWh of batteries may take a few hours.

The things will just refuse to be extinguished for a very long time, so the fire brigade will be pumping foam or powder, or CO2 in, and then have to do so with copious amounts, retreat, repeat, and so on.

 

Too many manufacturer sponsored YT videos showing how 'easily' these 'silly little fires' can be extinguished with a cup of tea in the other hand.

 

Utter bollocks. I've punctured lipo's that we use for racing RC cars, and the amount of anger stored in a box the size of a cooks matchbox is mind-blowing (eg run away and come back in 30 mins to see if it's calmed down yet). 

 

When we raced in community centres or leisure centres etc they were adamant that no lipos should be charged indoors at any time whatsoever. Some charged in their cars, outdoors in the carpark, and some cars went up in flames.

 

The facts dictate that these are minimal risk, so attempting to contain this type of fire inside a residence is a bit pointless; if it goes nuclear, feck all will save the building, you'll just have more time to wait for the fire brigade to smash the cupboard to bits and pump your house full of whatever they choose to use to attack the damn thing.

 

Attics are obviously now deemed the worst place to put one, as that's the highest point for the devastation to then drop through the house / into, toxic crap and all; and fire fighters won't be taking their shoes off to come into your house and ascend into the attic space to then unleash hell (of a lot of water or whatever else).

[Benpointer]

Just had our 27kWh Sigenergy batteries (LiFePO4) moved from the house to an outbuilding.  The main reason for doing that was due to the plant room getting very hot but, whilst I am prepared to believe these batteries are very safe, the thought of losing our new timber-framed house to a battery fire was, er... troubling.

 

If it goes up now I would lose my workshop but I reckon the fire brigade ought to have a good chance of stopping it spreading to the house 🤞

 

(The plant room is now running 7°C cooler on average btw.)

Edited yesterday at 17:35 by Benpointer
typo

[joth]

2 hours ago, Benpointer said:

Just had our 27kWh Sigenergy batteries (LiFePO4) moved from the house to an outbuilding.  The main reason for doing that was due to the plant room getting very hot but, whilst I am prepared to believe these batteries are very safe, the thought of losing our new timber-framed house to a battery fire was, er... troubling.

 

If it goes up now I would lose my workshop but I reckon the fire brigade ought to have a good chance of stopping it spreading to the house 🤞

 

(The plant room is now running 7°C cooler on average btw.)

It's an interesting trade-off, as batteries like it hot and this move will reduce the efficiency and lifespan of the batteries when used in the cold, in winter. If you're only using them for PV self-generated storage, that's probably moot, but if like me you fill from overnight cheap rate then it's rather a hit. That said with 27kWh you have a lot to play with.

I hadn't realised batteries could generate so much heat - presumably you moved the inverter too, and that was the actual heat-source? Unlike batteries, inverters do like it cold.

 

[Owain1602]

Depends what you mean by “batteries like it hot”.

The charge transfer processes can happen quicker at higher temperatures, so if your aim is to charge/discharge the battery at higher rates, then higher temperatures help with this. But high temperatures is the worst factor for increasing degradation rates for batteries. 
If the battery is LFP, then you have an already high baseline for the battery’s cycle life.

[Benpointer]

2 hours ago, joth said:

It's an interesting trade-off, as batteries like it hot and this move will reduce the efficiency and lifespan of the batteries when used in the cold, in winter. If you're only using them for PV self-generated storage, that's probably moot, but if like me you fill from overnight cheap rate then it's rather a hit. That said with 27kWh you have a lot to play with.

I hadn't realised batteries could generate so much heat - presumably you moved the inverter too, and that was the actual heat-source? Unlike batteries, inverters do like it cold.

 

Yes, the inverter too, it's part of the same stack.  Sloppily I just refer to the whole unit as 'the battery'.

[joth]

11 hours ago, Owain1602 said:

Depends what you mean by “batteries like it hot”.

Yeah by hot i mean "not cold", c.f. typical (historic) uk climate averages:

15-35°C is the ideal temperature range for LifePo4, which is much hotter than the uk average of 10°C