Battery Self install of battery storage

[littlespark]

I’ve been doing a fair bit of research on adding battery to my own house… there has been mention of it on other threads, but I’ll start a new one just for this.

Have been asking the “experts” in the local wholesalers, but I know they are salesmen first, and experts second.
However, saw this advert…



I’ve already got PV, with a good FIT price, so don’t want to affect that in any way.

The guy in YESSS said replace my existing inverter, and mount the battery’s next to it in the attic, but someone else has told me they are not to be in an attic for fire risk.


Can I fit the new inverter and battery’s separate to the PV? And not be limited to the <4kW?

The house heating is gas, but we can fit a few electric heaters to back that up…. Same with changing the gas hob to electric.

 

[littlespark]

I’ve gone with the offer, but only took the battery and inverter, none of the sundry items.

It got delivered to the house yesterday, and the battery box is H E A V Y

No idea how I’m going to get it into the attic.


I’ve not gone high… it’s a 3.6kW inverter, and a 5kwh battery… but as I’m paying, it’s more of a practice job.
Any paying customer, I’d push for higher.


All the instructions are online. And I’ve already got spare parts I don’t need.
There’s a usb type device with 2 screw connections that came with the battery, but I can’t find reference for it in the manuals.


I’ll have to see how to split my PV into 2 strings. I’ve definitely only got one, as there’s only 2 wires going into my existing inverter.

2 rows of 8 panels… so I’ll just have to split the rows.

 

[nicebutdim]

LiFePO4 chemistry is considered to be relatively safe, but I wouldn't place a bank of them in the roofspace of my house.

Investigators still uncertain about cause of 30 kWh battery explosion in Germany

A lithium iron phosphate (LFP) battery system recently exploded in a home in central Germany, preventing police and insurance investigators from entering due to the high risk of collapse. The explosion may have been preceded by off-gassing, but it remains unclear whether an external ignition...

www.pv-magazine.com

 

[littlespark]

I’m starting to think about extending the DC of the PV down the outside of the house and into the garage. (Vertically directly below the existing inverter.)

Might need to move my beer fridge or freezer…. Or a couple dozen Lego models… to fit it in… but it might be easier and safer.

Might even try on the outside wall… it doesn’t stick out as much as I thought it might. Just don’t want to knock it with the wheely bin.

 

[nicebutdim]

The chances of any issue is probably very low, but the potential consequences of those unlikely issues could be severe. If the garage is at all possible it's where I'd be looking to locate storage. Outside would be better again, but I'm not sure how that might work out in the long term with our climate.

 

[SparkySy]

I may be wrong but I'm sure Efix did a news cast or similar a few months ago saying latest guidance on battery storage was not to install in a loft!?

 

[littlespark]

I may be wrong but I'm sure Efix did a news cast or similar a few months ago saying latest guidance on battery storage was not to install in a loft!?

yes... ive heard from other installers about that... but theres nothing in MI i can find.

Id be putting in a smoke detector up there eventually anyway.

The Sunsynk invertor comes with a temperature sensor that just sits on the battery box... so will shut down if it overheats... andi was told in CEF that the ICS batterys... (not the ones ive gone for) have a self extinguishing feature.


Im going to measure the space in the garage and outside for suitability.... but theres still the extending of the DC cables from the PV....
Unless i make the battery and new invertor seperate to the PV invertor?? Leave the PV as is, and just charge the batterys from the AC going into the CU from the PV

There should be a way to control when to charge... just when the PV is generating.
Theres a CT clamp for measuring grid consumption.... so that could just be placed elsewhere?


More reading!

 

[SparkySy]

Not Efix but I did find this and it would seem that you can still fit them in lofts with certain safety precautions taken, as you say @littlespark a smoke detector is a must.

New British Standard Institute Recommendations for Home Battery Installation - Electrical Times

The British Standards Institute (BSI) has recently issued new recommendations which impact the location of home battery installations. PAS 63100: 2024, published in March 2024, states that solar batteries shall not be installed in ‘voids, roof spaces, or lofts’. The details outlined in PAS...

www.electricaltimes.co.uk

Personally, I would fit the separate inverter and battery in the garage or just outside if there is space and keep them as independent systems only connected through the mains, yes you will loose a bit due to inefficiency but at least if one side fails the other side will still be usable.
The unit will no doubt be configurable to do as you wish as you say more reading to be done on that one!

 

[nicebutdim]

The problem I see is that the amount of energy stored renders regular smoke detection redundant, should the worst happen. Even very early smoke detection systems would be of little use should that amount of energy be released in short order. Not only would the fire service have no chance of arriving in time to do anything, there's pretty much nothing they could do. With EV fires they can only sit back and watch, while trying to protect adjacent property.

 

[SparkySy]

Totally agree, I wouldn't fit one in a loft simple as!
Seen enough solar inverter fires that have been fitted in lofts and the results are always horrendous!

 

[Zerax]

I have installed my own battery solution based on a Victron (Very high quality) Inverter/Charger (5kVA) and LifePo4 cells. The cells are super cheap right now... you need a BMS to manage them, but it's all super easy to install and setup. Total cost for a system with 12kWh (usable) and 5kWh inverter/charger is about £2.5k... It means that my electricity cost is about 9.5p/kWh on average !

Happy to provide more details if you want...

 

[littlespark]

looking at the garage this morning.... the easiest position for battery is on an adjacent wall just under the boiler... with the invertor to the right of the boiler.... above the beer fridge.
I'll connect up as standalone, and leave PV as it is.

Any advice or guidelines about proximity to gas?



Boiler is high level wall mounted, with pipes above and below.
Fridge is regular undercounter size.
Freezer is tall unit. Will mount top of inverter level with top of freezer.
There are air vents to outside behind and above fridge (above inverter)

Main DB is through wall to left of washing machine. (unmarked) so running supply cable high level over door between DB and inverter.

 

[UNG]

Looking at the proposed battery location is it going to prevent removal of the boiler cover or make it more difficult to carry out repairs or maintenance on the boiler

 

[littlespark]

Looking at the proposed battery location is it going to prevent removal of the boiler cover or make it more difficult to carry out repairs or maintenance on the boiler

No… boiler is high up on wall. Battery box is on floor.
Here it is in position, not fixed, or connected up

 

[littlespark]

Ok… got everything connected up, just the AC connection to the installation.
I’m now second guessing myself as to what goes where.

I’m not connecting the PV directly to this inverter, so the solar side won’t give any readings.

Do I connect this inverter into the main tails, or into the PV between the existing inverter and the FIT meter?


There’s a CT goes on the tails… so it knows when import/ export.

 

[nicebutdim]

Cut the red wire.

 

[littlespark]

Cut the red wire.

There is no red wire… it’s brown now….

Unless you mean the big red one between the inverter and battery

 

[littlespark]

All up and running... batterys are charging off AC at the moment, which during the day is PV produced.

I do not have the DC from solar connected, so the readings on the invertor think its grid produced. (confusing)

There is a CT on the main tails that control a "no export" setting.... basically, if the grid is being used over solar feeding back, the charging stops. Hopefully, that means the batterys take over the load...

Guess i'll find out tonight when the sun goes down....

I could set up a timer within the invertor to only charge during set times.... (might mean use battery during set times as well... ill have to look at that)
That means i could have it shut down charging completely overnight when theres no sun... a reverse of only charging overnight on a cheap tariff


I'm now being asked to purchase an Earston meter and another CT clamp that would measure what it being produced by the PV....
is this just for information for the graphs on screen, or is it part of the charging control circuit?


I'm taking meter readings regularly from both my consumption meter and the generation meter that i read for FIT payments

 

[plugsandsparks]

You need a minimum of two CT clamps, there are a number of ways but easiest is to clamp the output from solar inverter and clamp meter tails. Then the battery will charge up instead of exporting to grid and supplement when solar output is not enough for home usage, it will try and keep the grid current to a minimum within its capabilities

 

[littlespark]

the time its been on so far, its been charging the batterys.... consumption meter hasnt gone up at all, so all from pv so far. i am hoping the "no export" setting recognises when the solar isnt producing and stops charging... so it doesnt pull from the grid, just to charge.

i will, in the future, extend the dc from the pv down the outside of the house to feed the inverter properly. maybe a length of 10m... but i think ill need to split the string

 

[Zerax]

the time its been on so far, its been charging the batterys.... consumption meter hasnt gone up at all, so all from pv so far. i am hoping the "no export" setting recognises when the solar isnt producing and stops charging... so it doesnt pull from the grid, just to charge.

i will, in the future, extend the dc from the pv down the outside of the house to feed the inverter properly. maybe a length of 10m... but i think ill need to split the string

Great stuff ! Any chance you could post a diagram of your setup ??