LiFePO4 batteries are very stable, so I'm not worried. That said, we have a mains wired smoke alarm directly opposite the cupboard they sit in and at night I open the door to let some of the inverter warmth out into the house.

@editor thanks Mars. Both the Growatt hybrid charger and inverter are fully metal clad to quite a decent IP level, most high end batteries are. I'll take reasonable precautions. I wondered if anyone else had, and if so what. Growatt publish a battery safety data sheet alongside the technical data sheet, which not all manufacturers do.

Happy new Year all. I drop in occasionally to read the latest posts in the forums, but I dont post much. I will update on our ASHP problems once I'm sure we have it sorted and the warranty is in place (long story).

I may consider PV and storage at some stage in the future as we are all electric. I have concerns over safety based on a little knowledge in the field. I would be particularly concerned that people are installing storage systems under the stairs, especially DIY. If/ when we install it will be external. I couldnt see any links in the forums to this report so thought it might be useful to include it here: 

GOV.UK "https://www.gov.uk/government/publications/domestic-battery-energy-storage-systems."

Domestic battery energy storage systems - GOV.UK

A review of the safety risks of domestic battery energy storage systems and measures to mitigate these.

Apologies if this is referenced elsewhere, but there is a lot of useful info in the report so hopefully it is of some help. 

Further to my last post on battery safety, I believe as part of any risk assessment we should consider this statement from another reference that I had seen in my professional capacity:

"In the UK current MSC guidance does stipulate that BESS can be located indoors, albeit with the caveat “5.7.1 All components shall be located so that escape routes from the premises are not impeded.” and “5.7.2 Storage batteries shall be located so that a fire in the battery does not compromise protected escape routes.” [198]. Although this does not necessarily mean second use batteries it does give some good advice on the location of batteries in general."

This is from

SCIENCEDIRECT.COM "https://www.sciencedirect.com/science/article/pii/S136403212100527X?via=ihub."

This report is focussed on automotive EV, but addresses the wider risks and second life usage as BESS. Please understand, I am definitely not anti EV or BESS, my background is technical risk management and failure avoidance. There are some further links to interesting reading via the authors, I would recommend anything by Prof Paul Christensen possibly the expert in this area.

Sorry if I sound like I'm obsessed, but I am not seeing a lot of focus on the risk and safety implications for battery storage systems (if it is covered and I've missed it I apologise) and especially for DIY installations. If any of you are spending time putting together any such systems I strongly suggest that you take the time (about 1 1/2 hrs) to listen to this lecture from Paul Christensen (I hope its OK to post this link?):

You may not like some of the messages, but it might save your family's life.

@dak51 interesting. Sadly the talk of BritishVolt's planned EV battery manufacturing plant at Blyth now has a very hollow ring.

I have a 6.5kWh Growatt battery at home, in the airing cupboard. I've fireproofed at loft hatch in the cupboard and installed a smoke alarm. I will also apply dry lining to the cupboard door inner leaf. This would not contain any fire or smoke, but buy time to get everyone out of the house safely in the event of a malfunction. Growatt batteries are fully metal clad and quite good IP, I've seen a one that had a thermal runaway, and the battery case did not rupture. Home EV storage batteries tend to be more robustly manufactured than car EV batteries, and heavier, since they can be. I would locate Li-Ion batteries in areas where a malfunction could impede egress from a house, such as under stairs, etc. I would certainly urge everyone to consider the high energy density of Li-Ion batteries, and that they can malfunction, although it is rare they do and home EV charging cycles tends to be much less stressful on the battery chemistry and integrity than EV fast charging cycles.

In my day job I'm working on dual redundant 2 x 150kWh UPS Li-Ion battery systems, Siemens BlueVault industrial UPS batteries. We're into a lot of detail discussion with various engineering and safety disciplines, and 3rd party regulatory authorities, about the installation of these systems and the safety systems required in conjunction with them. Siemens use water cooling jackets around each cell, to contain any thermal runaway. A Siemens video of just one cell malfunctioning is quite spectacular, and how fast in real time the event happens. The battery rooms the BlueVault systems are going into will have self-contained redundant 2x100% fire/explosion proof ventilation extract systems. The off-gasses generated by a thermal runaway are highly toxic and combustible. They have to be contained and ventilated to a safe external dispersal point. We're also considering active fire suppression or water mist for the battery rooms. The rooms will be A60 fire rated structures.

Thanks for the video. 

I don't think i would take the risk of installing a battery inside the main fabric of my home or  loft after seeing that if there were other options. Particularly any DIY install, but any install to be honest. I think i would simply be worrying about it too much. Just not worth the risk, however i tried to quantify it. 

Posted by: @batalto

↑

LiFePO4 batteries are very stable, so I'm not worried. That said, we have a mains wired smoke alarm directly opposite the cupboard they sit in and at night I open the door to let some of the inverter warmth out into the house.

If they did start emitting toxic gas, could you get out of the house without going anywhere near the battery? 

Am just curious about what people are doing. 

Just to highlight in general that many modern home storage battery systems are now Lithium Iron Phosphate cell technology, as distinct from Lithium Ion.  A view on the comparative risks of failure of the two cell technogies would be extremely helpful.  Related guidance to date seems to have been directed towards Lithium ion.

Posted by: @skd

↑

Just to highlight in general that many modern home storage battery systems are now Lithium Iron Phosphate cell technology, as distinct from Lithium Ion.  A view on the comparative risks of failure of the two cell technogies would be extremely helpful.  Related guidance to date seems to have been directed towards Lithium ion.

Personally i would still look to limit the risk by locating the battery outside the main fabric of my home if at all possible. 

It wouldn't actually make any difference to me what the relative risk was, i would simply look to minimise it for my family if i could.