I don't have any experience and I don't know how to assess the risk - especially for a product that does not yet exist! I do know that batteries in the past have exploded, or in other words a fire might spread very quickly. I'd be looking for a lot of assurance that there wouldn't be any fires. For a new product from what I presume is a newish company it's difficult to see how that could be provided.

That's a bit of a hike to the toilet ? :)

Thanks for the helpful comments; the battery/inverter part of the product isn't new, the AI bit that decides when to buy & sell, is the new part. I think they're timing release to coincide with their access to the Swedish aggregator market. It's a Danish product, been there for a few years I think, but their website is a bit sketchy on details, e.g. no address ...

Yes, block wall, concrete floor, slate roof, and further away would be preferable.

How about that - we had also been considering another "outside" model, that's a bit more established - Ferroamp - and while composing this reply, I found the following text on their website (https://ferroamp.com/en/products/batteries/):

"Are Ferroamps batteries fireproof? Ferroamp’s batteries are based on lithium iron phosphate (LiFePo), which is a battery chemistry characterized by being thermally stable. This means that the batteries are fireproof and do not cause uncontrollable battery fires thanks to the very low risk of thermal runaway."

The Ferroamp battery also seems to check a few more IEC standards

revor - how does the battery perform at low temperatures, round zero?

Posted By: philedgerevor - how does the battery perform at low temperatures, round zero?

The spec says environment of 0 to 25 c. Optimum Operating temp 15 to 20 c for longer life. The room it is in is fairly small and I have a 60 W tubular heater in there to keep from going too low in winter. The walls and roof are insulated and have a DG window in there. The battery is warm most of the time because it is either charging or discharging. My inverter operates up to 50 c so that warms up the room. As I write battery is at 27.4 and inverter 42.00. If doing again I think I would go for the safer chemistry.

Appreciate you've already likely committed to a design/product, but adding AC or DC coupled batteries doesn't necessarily affect your FIT payments. OFGEM changed the scheme rules a few years ago to allow significant changes without voiding payments in respect of the original system capacity.

For philedge; DC coupled was more expensive and pushed the ROI further out than I was comfortable with.

For revor; Agreed, no guarantees; I wanted a company that made the whole lot inverter, battery assembly,
etc.. I guess the UK domestic BESS is still small, albeit growing, and maturing. I figured companies that had a strong presence now would maintain that presence, there were other considerations too.

Typically low voltage storage batteries are less than 100V. High voltage ones usually around 400V, mine have a nominal voltage of 384V. High voltage is usually a better build quality with better cells, there are other advantages.

I'm not familiar with Ferroamp, but looking at their pictures it appears they are using Pylontech battery modules together with their own, presumably?, battery management system etc.. Several other BESS suppliers on the market use the same approach. AFAIK Ferroamp's main forte is in developing a home energy hub, but I don't know if they actually manufacture anything.
I chose not to go down this, mix and match route, because of any future conflict of responsibility should a problem occur, and therefore any 10 year warranty issues could look messy.

I'm not DIYing it's been professionally fitted as all BESS should be.
In my case because I've got 10kW of grid tied solar PV I need DNO approval. I also wanted the install to be capable of operating in a partial Island mode should there be a power outage. As a result, I also chose high voltage storage because of its higher charge and discharge rates and higher inverter and overall efficiency.

philedge: "Not sure why battery manufactures call their batteries "high voltage" in the UK as high voltage is >1000vac/15 00vdc." - yeah, same in Sweden - that's where I was getting confused; like where I work - there's only one electrician who's qualified/allowed to work with high voltage

Posted By: minisaurusThat's a bit of a hike to the toilet ? :)

"Ferroamp’s batteries are based on lithium iron phosphate (LiFePo), which is a battery chemistry characterized by being thermally stable. This means that the batteries are fireproof and do not cause uncontrollable battery fires thanks to the very low risk of thermal runaway."

Almost all home batteries are LFP. Early Tesla ones weren't but I think they've changed to it now too. I recall one other supplier using NCM/LCA. I forget who.

LFP is pretty safe and really quite hard to set fire to. I'm not sure why everyone is quite so worried about this. Apart from that one German house that blew up for mysterious reasons, how many actual domestic BESS fires have there been? Were any of those LFP? Were any caused by exploding batteries, as opposed the usual electrical fires from overheating connections/cables?

I guess there must have ben at least one fire in Australia because they implemented quite strict rules a couple of years ago that all batteries must be outside in a steel box.

All the battery fires I'm aware of are cars (which aren't LFP) or scooter/e-bike batteries (usually of low-quality or abused with the wrong charger), or large utility-grade systems.
There is an industrial incident database: https://storagewiki.epri.com/index.php/BESS_Failure_Incident_Database
But I've not found a domestic equivalent, nor any actual incidents - just a lot of people worrying about them.
Of course the utility-grade stuff catching fire is not a good look - they _ought_ to know what they are doing and it demonstrates that BESS fires are possible. They are typically getting about 0.3 fires per deployed GW so for the say 10kW per house that would be 3 fires per million house deployments. I'm not sure where that comes on the available risk range but it doesn't sound too bad.

Now I've read the whole article & comments - the guy had three inverters and two different LFP battery types, both purchased from alibaba, and there are questions over the CE conformance & compatibility of the batteries. As well as unknown cause of explosion. Hmm

Posted By: owlmanAlibaba; Hmm indeed. You pays your money and ..............?

My battery install is taking place in 10 days time. I've gone for an initial 20.75kW of storage with a provision to upgrade to 31kW, within the same outdoor enclosure. The whole system will be controlled by a single 10.5kW hybrid inverter, and is capable of being increased to a max. of 41.5kW.
I've done all the preliminary stuff, switching tariffs, installing a smart EV charger, DNO approval, reconfiguring consumer board, auto time switching immersions, etc., so anxiously awaiting results.

So not exactly plug and play.

Any idea how much extra it would be to get it plug and play? (and could you get a one stop shop to do it?)

The battery charge and discharge rates and times are set on the manufactures App as is system monitoring.
In the absence of PV production the battery is set to charge at cheap overnight rate and discharge to the home over the remaining period. If there is PV available after prioritised house baseload the following day, the battery re-charges so as not to incur Grid charging the following overnight.

Chance would be a fine thing, and the issues maybe too complex. Interfacing, and to some extent balancing and managing, Solar PV, the Grid input, EV charging, daily home usage, plus battery charging and Grid outages etc., are more than any plug and play, "buy it on Amazon", could cope with.