Green Building Forum - Safety - re battery storage of solar energy

Safety - re battery storage of solar energy

minisaurus — Sat, 07 Sep 2024 14:36:02 +0100

We'd like to purchase a battery system for storing electricity generated from our solar panels. Our only indoor option is to place the battery in our wooden shed (340 cm wide, 270 cm deep, 235 cm high). The battery package we like is this: https://emaldo.com/products/emaldo-power-store-ai; it complies with IEC62619:2022 safety for industrial batteries, and is designed to stand & store outdoors in the nordics.

I'm worried about fire - our house is also wooden and positioned 80cm from the shed. We'll have to install an industrial grade smoke & heat detector with a loud alarm so we get woken up in case of fire.

Does anyone have experiences or opinions on assessing the risk of fire in such settings? And how fast a fire might develop/spread?

Safety - re battery storage of solar energy

djh — Sat, 07 Sep 2024 16:20:44 +0100

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.

Safety - re battery storage of solar energy

revor — Sat, 07 Sep 2024 16:24:40 +0100

When I considered our battery I had already decided it was going to be outside. I repurposed an outside loo (block built slate roof concrete floor.) House nearest wall 6m away. Even so I did not think that some of the batteries on offer were that well constructed fairly thin casing of "rack" design so you could stack together usually multiples of 2.5kw units. I settled on a German made battery with cells made in Korea built into a heavy duty casing. It has a lot of protection built in against overheating linked to the inverter which will alarm but I have not got a sounder linked to it. The Emaldo is new to me have you actually seen one and satisfied yourself that the casing would be a reasonable barrier if it ignited? Might be worth running past you insurer. I was asked questions about our system when I changed insurer last year and they were happy it was outside and not in the house. Think you would need to declare as if you did have a claim they would try and wangle out of it. Having said that I need to reassess the risk as now got an EV and that is normally parked between the battery house and the house!!

Safety - re battery storage of solar energy

minisaurus — Sat, 07 Sep 2024 17:26:11 +0100

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?

Safety - re battery storage of solar energy

philedge — Sat, 07 Sep 2024 19:03:01 +0100

A good measure of a manufacturers quality is if they're aware of and comply with a countries rules and regs. The only emaldo product on the ENA type test register is a 3 phase inverter that isn't approved for connection to the UK grid.

Maybe they have compliance in hand but they'd be more credible if they were a tad more accurate- their data sheet suggests they comply with "G98 2022" but the register suggests otherwise!

Safety - re battery storage of solar energy

revor — Sat, 07 Sep 2024 19:27:32 +0100

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.

Safety - re battery storage of solar energy

owlman — Sat, 07 Sep 2024 19:46:40 +0100

I've just accepted a quote and paid the deposit for a battery storage system to complement my two solar arrays. I'm installing outside against my bungalow brick wall. I'm raising the batteries off the floor on a super strong platform which will be lined with FR material, all inside an enclosure I'm building. I was aware of some fire risk with earlier lithium batteries, but I understand that the LiFePO4 as you say, are much safer.
I've chosen high voltage batteries because I needed an AC tied system, ( I wasn't prepared to mess about with my FITs), and they are more efficient than LV batteries. I will take all the fire precautions I can to protect both my home and investment.

Speaking to loads of battery fitters, UK manufacturer representation is what they look for. They prefer UK based service back up. Although loads of home battery systems are available from a myriad of manufacturers from around the world If you're in the UK best to check this aspect out.

Safety - re battery storage of solar energy

philedge — Sun, 08 Sep 2024 13:06:23 +0100

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.

Safety - re battery storage of solar energy

revor — Sun, 08 Sep 2024 13:36:54 +0100

Posted By: owlmanSpeaking to loads of battery fitters, UK manufacturer representation is what they look for. They prefer UK based service back up. Although loads of home battery systems are available from a myriad of manufacturers from around the world If you're in the UK best to check this aspect out.

It is no guarantee. Both my inverter and battery are of European origin and both were supported by an UK agent. The agent although very helpful to start switched to other activities and no longer deals with the manufacturers of my components. No alternative agency in the UK has taken up the dealership of either battery or inverter. I have very good relationship with the inverter manufacturer and confident they would help out if needed but cannot get battery manufacturer to interested even though I was seeking to increase my battery capacity.

Safety - re battery storage of solar energy

owlman — Sun, 08 Sep 2024 14:47:03 +0100

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.

Safety - re battery storage of solar energy

minisaurus — Tue, 10 Sep 2024 17:26:09 +0100

Posted By: owlman
I've chosen high voltage batteries

- is that, like, over 1000 volts?

(Oops, I can never remember how to do quotes here, I pressed the 'quote' button of course ...)

Safety - re battery storage of solar energy

owlman — Tue, 10 Sep 2024 22:48:38 +0100

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.

Safety - re battery storage of solar energy

minisaurus — Wed, 11 Sep 2024 08:56:04 +0100

Ok, thanks Owlman, it seems the ferroamp voltage increases with the number of batteries? So with 4 batteries you get 384 V

Safety - re battery storage of solar energy

owlman — Wed, 11 Sep 2024 09:36:14 +0100

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.

Safety - re battery storage of solar energy

RobL — Wed, 11 Sep 2024 11:14:45 +0100

Low voltage batteries are <60V, getting them into the "Safety Extra Low Voltage" category (SELV). In contrast high voltage batteries are just that - there must be hugely more caution as it's a lot more dangerous than mains AC. All things being equal, high voltage battery inverters are likely to be slightly more efficient, and use thinner battery bank connection cables. I work with high voltages for a living, and chose a low voltage diy system.

Safety - re battery storage of solar energy

owlman — Wed, 11 Sep 2024 12:40:09 +0100

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.

Safety - re battery storage of solar energy

philedge — Wed, 11 Sep 2024 13:43:20 +0100

Not sure why battery manufactures call their batteries "high voltage" in the UK as high voltage is >1000vac/1500vdc.

Safety - re battery storage of solar energy

minisaurus — Wed, 11 Sep 2024 14:09:05 +0100

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

Safety - re battery storage of solar energy

owlman — Wed, 11 Sep 2024 14:43:29 +0100

I don't think it's a technical SI thing, simply a moniker that domestic SESS system suppliers and fitters use to broadly differentiate between two different battery classes.
There are so many battery storage systems with the lets say " lower voltage" but with a V. anywhere between 50 and 100V. The "higher voltage" ones usually with a nominal voltage around 400V.

Safety - re battery storage of solar energy

wookey — Wed, 11 Sep 2024 15:37:01 +0100

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.

Safety - re battery storage of solar energy

minisaurus — Sat, 12 Oct 2024 12:31:18 +0100

Just found this interesting article about the explosion in Germany, interesting comments underneath the article: https://www.pv-magazine.com/2023/10/30/cause-of-30-kwh-battery-explosion-in-germany-remains-unclear/

Safety - re battery storage of solar energy

minisaurus — Sat, 12 Oct 2024 12:43:19 +0100

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

Safety - re battery storage of solar energy

owlman — Sat, 12 Oct 2024 13:46:38 +0100

Alibaba; 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.

Safety - re battery storage of solar energy

Peter_in_Hungary — Sat, 12 Oct 2024 14:16:55 +0100

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?)

Safety - re battery storage of solar energy

owlman — Sat, 12 Oct 2024 14:26:30 +0100

Sorry Peter I'm not with you; "plug and Play? "

Safety - re battery storage of solar energy

owlman — Sat, 12 Oct 2024 14:34:47 +0100

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.

Safety - re battery storage of solar energy

Peter_in_Hungary — Sat, 12 Oct 2024 14:55:25 +0100

Posted By: owlmanSorry Peter I'm not with you; "plug and Play? "

plug and Play - As in wheel it in through the door, plug it in and off it goes without the new owner needing to do any laborious setting up with inherent wrong choices being capable of being made.

A bit like computers used to come as a machine and boxes software that needed a techie to install and set up before anything useful could be done

Now plug and play is the name of the game, you bring it home from the shop plug it in and start using it.

Safety - re battery storage of solar energy

owlman — Sat, 12 Oct 2024 18:30:57 +0100

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.

Safety - re battery storage of solar energy

djh — Sat, 12 Oct 2024 19:41:09 +0100

If you want plug and play buy it from a firm that installs a well-known brand. And ideally a firm that has 'good reviews'.