Lithium at home

[suavecarve]

Having read a few threads that mention having a lithium bank at home and charging with cheap electric/solar then using an inverter to change it from 48v to 240v

I have a nephew who can connect everything from the sparky point of view and am looking at 20-30 kw of power bank and fallen in with the starter of 20 kw and case from fogstar for £3999. https://www.fogstar.co.uk/collectio...utdoor-battery-cabinet?variant=54917410390393
From the little I understand I need that placed outside (under lock) then I need a charger of some description to charge it up overnight during cheap electricity rates and an inverter

I have worked out our usage and we are very heavy users of electricity as it is basically 2 homes and will probably buy another 5 kw but I will wait to see

What are the options for the charger (I see that eon will put one on your drive for a grand if you pretend you have an electric car) but that might not be necessary if there is some form of smart charger AND what inverter and does that have to be inside (or does it fit inside the cabinet).

What else am i not thinking about ?

 

[Carpmart]

Following as interested in doing similar myself!

 

[MisterB]

I can recommend the Sunsynk inverter, we have a 5kw but wish I had gone for an 8kw, at some point I will buy an 8kw and sell the 5kw.

We do exactly what you're trying to do and it's been one of the best things we've done in terms of reducing costs (we are all electric with storage heaters) and bought an EV to enable us to go into a cheap tariff.


Raul can offer great technical and practical information

 

[DBK]

An interesting project.

Do you want to entirely power your house from batteries during the day or keep the option to use the battery power to supplement the mains power. If the latter you will need a system which matches the phases.

I think you would want the system to be automatic so you are not manually changing over, which would probably entail turning off any computers first unless they have UPS and resetting all the clocks of the kitchen appliances.

I guess it's about either going down the DIY route or consulting a company who have done this before. You would also want to look at the legal side and how much of the installation you are allowed to do where you live.

I'm assuming you've done the sums and this is cost effective for you.

 

[suavecarve]

An interesting project.

Do you want to entirely power your house from batteries during the day or keep the option to use the battery power to supplement the mains power. If the latter you will need a system which matches the phases.

I think you would want the system to be automatic so you are not manually changing over, which would probably entail turning off any computers first unless they have UPS and resetting all the clocks of the kitchen appliances.

I guess it's about either going down the DIY route or consulting a company who have done this before. You would also want to look at the legal side and how much of the installation you are allowed to do where you live.

I'm assuming you've done the sums and this is cost effective for you.

More or less entirely power the house from the batteries on a daily basis and when they run out use the normal electric supply.
I would want it to be automatic in that each night it charges at cheap time and only moves over to regular supply when out of battery
The FiL was a sparky but that is getting on for 30 + years ago now. But the DIY route is covered by the nephew sparky or his mate to sign off on the electrics but all the "work" to get to that stage will be by us.
I have no idea of legalities of how many batteries I am allowed. There will be no solar as we already have the max on the roof and it wont touch what we need

Here is our bill for January this year when all 4 of us were in the house and 2 motorhomes were charging on the drive (til I saw how much electric we were using). Other months are much more realistic and there is an argument for 30 kw but it is a grand for every extra 5kw so starting with 20 or 25

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[suavecarve]

I can recommend the Sunsynk inverter

I see this is a solar inverter and we wont be inputting our solar into the batteries (our ridge literally runs north to south and have electric panels on the west facing and water heating panels on the east facing roof) so we dont get that much and we sell any excess back on the pre 2011 installation system of 60 p ish a kilowatt

But it has got me thinking if we could you use the 600 watts of solar panel we have on our motohome roofs to supplement the charge into the batteries

 

[lorger]

As you already know we do this already, don’t use anywhere near what you do but still working out ok.

We have 10kw battery that we charge between 00.01am and 6.29 am at 6.7p KW, we also set the dishwasher and washing machine to come on in between these times. We use roughly between 6-8 kw a day so battery should see us through the day, we also have solar that we get paid 16p kw for export. Every day this month we’ve exported more than 45kw a day so far, we’re hoping payback will be somewhere between 7-9 years.

Most other companies that offer the cheap rate require you to have an ev but Eon just require storage systems, although I think you need all the certificates and system approved by local network providers.

 

[Rollingwheels]

The Electrician will need to be MCS registered for it to be connected and certified correctly. Or someone he knows to sign it off but if he is a Sparky he will know that anyway, we are building a new house at the moment and I am considering the Fogstar but all of the MCS registered guy want to use their own kit to make more money ..

 

[neilydun]

More or less entirely power the house from the batteries on a daily basis and when they run out use the normal electric supply.
I would want it to be automatic in that each night it charges at cheap time and only moves over to regular supply when out of battery
The FiL was a sparky but that is getting on for 30 + years ago now. But the DIY route is covered by the nephew sparky or his mate to sign off on the electrics but all the "work" to get to that stage will be by us.
I have no idea of legalities of how many batteries I am allowed. There will be no solar as we already have the max on the roof and it wont touch what we need

Here is our bill for January this year when all 4 of us were in the house and 2 motorhomes were charging on the drive (til I saw how much electric we were using). Other months are much more realistic and there is an argument for 30 kw but it is a grand for every extra 5kw so starting with 20 or 25

View attachment 1039663

Im glad its not just me....

 

[mikebeaches]

View attachment 1039663

Blimey 1286 kWh - that's quite a lot. I know we use oil for heating, but our electricity (including all cooking) from the grid in January was less than 35 kWh. We've got some solar and 13 kw of battery storage.

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[MisterB]

I did most of my own install and had a qualified and competent sparky to do all the connections etc.
running cables, clipping them to the wall and fitting other stuff to the wall, drilling holes etc as an apprentice would do is, in my opinion, not against the law, though I suspect the keyboard warriors may have another view.

I even assembled my own batteries ....

I was also lucky enough to encounter someone who helped me fill in the paperwork to obtain the correct approvals.

 

[suavecarve]

'm assuming you've done the sums and this is cost effective for you.

Still wortking out the sums.
£4-5 k for the batteries
Inverter and charger say 1500. Call it £7K

If I use more than 20kw every day then I will save about £5 a day or 150 a month or 1800 a year so it pays for itself in 4 years.

The warped way I am looking at it is ............... If I withdraw £7k from my premium bonds I win £150 a month ! I seem to rarely win 150 off 40k savings

I also found out this week I wont be working again so planning for the future.

 

[suavecarve]

Blimey 1286 kWh - that's quite a lot. I know we use oil for central heating, but our electricity from the grid (including all cooking) in January was less than 35 kWh. We've got some solar and 13 kw of battery storage.

View attachment 1039683

When we arent even here !

 

[suavecarve]

The Electrician will need to be MCS registered for it to be connected and certified correctly. Or someone he knows to sign it off but if he is a Sparky he will know that anyway, we are building a new house at the moment and I am considering the Fogstar but all of the MCS registered guy want to use their own kit to make more money ..

I m hoping this is where the Nephew in law comes in. His workmate (or him) fit the solars etc and can sign it off leaving us to do the work

 

[MisterB]

I see this is a solar inverter and we wont be inputting our solar into the batteries (our ridge literally runs north to south and have electric panels on the west facing and water heating panels on the east facing roof) so we dont get that much and we sell any excess back on the pre 2011 installation system of 60 p ish a kilowatt

But it has got me thinking if we could you use the 600 watts of solar panel we have on our motohome roofs to supplement the charge into the batteries

We also have a FiT system and receive payments, any excess from being used in the house firstly goes to charge the batteries and then goes to the grid. We are on deemed use tariff so get paid whatever we do with our excess.

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[neilydun]

We have a Givenergy system & 3.5 kw solar.
The Givenergy system works very well and is easy to control or automate, but I think your route is much better value for money.
2x grown up children & there baby have just bought there first property, so I am hoping next winter, the bills will be less !

 

[suavecarve]

We also have a FiT system and receive payments, any excess from being used in the house firstly goes to charge the batteries and then goes to the grid. We are on deemed use tariff so get paid whatever we do with our excess.

If the excess goes to the house first then the excess from that goes to the batteries does that mean your FiT payments diminish as you could charge your batteries with the 7p overnight rather than having to fill it up with electricity they pay you 60 for

Or have I missed something ?

 

[mikebeaches]

When we arent even here !
View attachment 1039684

May 2024 - circa 16.5 kWh for us and the weather was a bit disappointing as I recall.

 

[mikebeaches]

Should have said, same month 656 kWh exported to the grid, worth a credit of £104.93.

 

[suavecarve]

Should have said, same month 656 kWh exported to the grid, worth a credit of £104.93.

View attachment 1039701

We only get just over a grand for the whole year. We put the same system on the daughters house 200 yards away at the same time which has a lovely south facing pitch and she gets £2,5k pa

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[dunnah01]

Bloomin Eck. We're all electric in the house and use about 300kwh/month winter and 80kwh/month in summer. Add about £5 of LPG and diesel in Moho.

 

[MisterB]

If the excess goes to the house first then the excess from that goes to the batteries does that mean your FiT payments diminish as you could charge your batteries with the 7p overnight rather than having to fill it up with electricity they pay you 60 for

Or have I missed something ?

I am on the 50% deemed but the second tranche so don't get 60p per KW - I am on the cusp of which is the greater payback, should I sell all my surplus or stick with the deemed payment. If I was on the first tranche then I would probably be doing what you're contemplating. However if the conversation is about the engineering not the fiscal decisions, then do it yourself, with the help of your son in law..

 

[Cobra]

We are very high consumers..
We have 4kw solar
Before I setup my batteries we were using about 1000kw - 1500kw per month on standard rate electric and paying back 40-50% of my solar generated electricity (I’m on an old FIT payment system)
Once my full system was commissioned (by me) we are down to about 550kw with only about 5-8% of “expensive” electric (sometimes a lot less) used. Almost nothing is ‘paid back’ from the solar, with it all being used to run the house and charge the batteries
We have 31 kwh of Fogstar battery storage (2x 15.1kwh pre made - cost £5k) and a Victron Multiplus II 5000va inverter/charger
I have also fitted a 35amp additional charger to speed up overnight charging (also Fogstar)

My current tariff gets me 11p at night and 27p during peak as I don’t have an EV and am on the equivalent of the old ‘economy 7’ rate (Octopus)
My batteries are charged by excess solar during the summer with an overnight charge in the winter (at 11p per kwh) of anything up to 100%, depending upon solar forcast

I haven’t had a full summer yet so don’t have all the figures but expect my system to pay for itself within approx 5 years (with min 8 years guaranteeon the batteries)

Andy

 

[suavecarve]

We are very high consumers..
We have 4kw solar
Before I setup my batteries we were using about 1000kw - 1500kw per month on standard rate electric and paying back 40-50% of my solar generated electricity (I’m on an old FIT payment system)
Once my full system was commissioned (by me) we are down to about 550kw with only about 5-8% of “expensive” electric (sometimes a lot less) used. Almost nothing is ‘paid back’ from the solar, with it all being used to run the house and charge the batteries
We have 31 kwh of Fogstar battery storage (2x 15.1kwh pre made - cost £5k) and a Victron Multiplus II 5000va inverter/charger
I have also fitted a 35amp additional charger to speed up overnight charging (also Fogstar)

My current tariff gets me 11p at night and 27p during peak as I don’t have an EV and am on the equivalent of the old ‘economy 7’ rate (Octopus)
My batteries are charged by excess solar during the summer with an overnight charge in the winter (at 11p per kwh) of anything up to 100%, depending upon solar forcast

I haven’t had a full summer yet so don’t have all the figures but expect my system to pay for itself within approx 5 years (with min 8 years guaranteeon the batteries)

Andy

Your usage is similar to ours. The multiplus only charges at 32 amps so I see why you have the extra 35 amp charger which makes me think the Eon car charger which does 60 kw in 8 hours might be a better option for us and I presume I need an inverter (probably 8kw) extra. It is 2/3 houses on the same electric supply so air fryers are used at the same time.

 

[Cobra]

The Multiplus 5000va charges at 70 amps
I am seriously thinking about upgrading the Multiplus to 10000va or 15000va
I confirmed with Fogstar that if I want, I could add almost any number of additional chargers if required
The larger Multiplus also charge at much higher rates - 140amp for example with the 10000va

You can, of course, add additional Multiplus to increase the overall output (e.g 2x 5000va to give you 10000va)
If you do this the Multiplus MUST be identical (firmware, batch etc) so I would only advise that you buy them as a pair from a reputable source.

If/when we buy an EV then I will probable buy additional batteries and increase the inverter sizing so that I can charge whenever I want
(Having charged the batteries with either solar or cheap rate overnight electricity)

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[Cobra]

A couple of things to think about if you go for one or more Multiplus
My 5000va will also produce an isolated load of 20amps (about 4800 watts) through a separate output EVEN WITHOUT A GRID SUPPLY
This basically means that, if wired correctly, if you have a power cut, you can still have power (by using power stored in your battery) on selected circuits.
In practical terms; this means my Boiler, PC UPS, Router & Switches, downstairs lights and a few other 'essential' circuits are always available should I loose grid power.
Initially, I used a separate consumer unit with these circuits in. After some thought, I decided to replace my whole consumer unit with a 'Double' one with my normal circuits on the top and a separate feed, directly from the Multiplus, to the bottom half of the CU with the 'protected' supply feeding the boiler, lights etc.
I have configured the multiplus to 'save' 20% of the battery so that if I loose grid power, I will always have at least 6kwh to use in an emergency (plus any power in the battery above the saved 20%)
This was one of the main reasons I went for this brand

One more thing to investigate:
The multiplus 5000va is now finally accepted and certified for connection/feed-in etc by the DNOs
I'm not sure about the bigger ones yet.

 

[gus-lopez]

I took the lazy way here in spain & bought a 4Kw power bank to run the house supplemented by two,at present , 2,6kw batteries so around 9kw in total. The power bank is charged via 3 x 465w panels & the batteries are charged via 6 x 465w panels & the batteries charge/feed in to the power bank also via the low voltage soar input. On a reasonably sunny day,like today, the power bank which started at 8am being 40% full & the batteries that were at 70% & including the immersion heater being on from 11am .the power bank was fully charged by 12 noon& stops intake of power, & the batteries were at 90% & will be fully charged soon.
We installed with only one additional battery at the end of november & it ran ok until we had a prolonged period of cloudy weather when the second battery would have helped.
It is standalone from the incoming main with only an automatic change over switch if it goes off switching it back to the mains.
the panels are in sets of 3 in different places & yesterday all 3 sets of three were happily giving there full 1400w of power input.
As it is not attached to the grid, no point as you are only providing power foc for them to sell to someone else , there is no requirement to have an electrician install anything, & that was the point to become completely independent from the grid.

e I understand I need that placed outside (under lock)

Mine are all in the hallway next to the meter

We never used that amount in a year even using ac in summer on occasions & running the swimming pool pump 4 hours/day

I also found out this week I wont be working again so planning for the future.

sorry to hear that

rather than having to fill it up with electricity they pay you 60 for

In the UK they pay you for generating the electricity even if it is all used by you.