Solar and house battery installation

[DBedford]

That's not quite true, most hybrid inverters have the EPS (Emergency Output Supply), it's just most installers don't bother to connect them up. The simplest for is to energies a 13amp socket somewhere then items that you wish to power during a power outage can be plugged into it.


My panels and batteries were installed a year ago. My calculations were straight forward, look at the energy price increase (my fixed tariff was ending) my payments were going up from £170 per month to £540. I couldnt bring myself to pay that increase. The quote for my solar 6.7kW panels, 7kWh battery and a 6kW inverter along with energy diverter for immersion came to just under £12k. I took a loan out for 6 years at £206 per month. The real figures of payback can now be assessed having run for a year. My energy bill is actually £142 per month instead of £540, a saving of £398. The £398 more than covers the loan payments so my break even point is immediate!


Since that install, I was still taking some peak rate energy at times due to battery capacity and inverter power. I looked carefully into how to resolve this issue and I ended up making a 14kWh battery with it's own inverter housed in a small tool shed round the side of my house. This AC coupled battery charges from both solar and off peak energy resulting in all of my electricity being free (from solar) or from off peak at 7.5p kWh. The DIY approach is not difficult, all of the info is out there, it's just well hidden by many. Commercial quotes for this level of storage and inverter were in excess of £16k, this cost me less than £4200 and a bit of head scratching.

View attachment 17814
This is my little toolshed

View attachment 17815
The lower part has the batteries installed (3 shown here, each module contains 4 EVE cells).

View attachment 17816
The top half housing the inverter, the BMS and the fuses / switch gear.

This system was switched on 24th December and cooked our Christmas dinner, it has been completely untouched, just sitting there doing what it should.

Several people have now followed the above and are enjoying the same result. If you are DIY inclined, you can build such a system easily and even if you use an electrician to connect up to your grid supply, massive savings can be achieved.

£

That's not quite true, most hybrid inverters have the EPS (Emergency Output Supply), it's just most installers don't bother to connect them up. The simplest for is to energies a 13amp socket somewhere then items that you wish to power during a power outage can be plugged into it.


My panels and batteries were installed a year ago. My calculations were straight forward, look at the energy price increase (my fixed tariff was ending) my payments were going up from £170 per month to £540. I couldnt bring myself to pay that increase. The quote for my solar 6.7kW panels, 7kWh battery and a 6kW inverter along with energy diverter for immersion came to just under £12k. I took a loan out for 6 years at £206 per month. The real figures of payback can now be assessed having run for a year. My energy bill is actually £142 per month instead of £540, a saving of £398. The £398 more than covers the loan payments so my break even point is immediate!


Since that install, I was still taking some peak rate energy at times due to battery capacity and inverter power. I looked carefully into how to resolve this issue and I ended up making a 14kWh battery with it's own inverter housed in a small tool shed round the side of my house. This AC coupled battery charges from both solar and off peak energy resulting in all of my electricity being free (from solar) or from off peak at 7.5p kWh. The DIY approach is not difficult, all of the info is out there, it's just well hidden by many. Commercial quotes for this level of storage and inverter were in excess of £16k, this cost me less than £4200 and a bit of head scratching.

View attachment 17814
This is my little toolshed

View attachment 17815
The lower part has the batteries installed (3 shown here, each module contains 4 EVE cells).

View attachment 17816
The top half housing the inverter, the BMS and the fuses / switch gear.

This system was switched on 24th December and cooked our Christmas dinner, it has been completely untouched, just sitting there doing what it should.

Several people have now followed the above and are enjoying the same result. If you are DIY inclined, you can build such a system easily and even if you use an electrician to connect up to your grid supply, massive savings can be achieved.

£540 a month on electricity!!!!, yes I can you what has motivated the change.

This Winter we peaked at £116/months so right now the sums just don’t appear to add up , and plus the fact we are both 66.

 

[Gadget Geek]

£

£540 a month on electricity!!!!, yes I can you what has motivated the change.

This Winter we peaked at £116/months so right now the sums just don’t appear to add up , and plus the fact we are both 66.

With your low usage, you would probably benefit from running items upto 2.5kW off the car via the V2L adapter with an off peak tariff to charge back up.

Edit: What items do you run regularly and have a look at their labels to see the poweer consumption. The V2L adapter will happily run a kettle, microwave, toaster, etc. (There are a couple of threads on V2L where people are doing this).

 

[johnb80]

I would charge from Octopus BG if it was that easy, but my understanding is:

1) Each supplier needs ‘their’ own (Gen 3) smart meter installed to work with their tariff,

No, SMETS2 meters are universal between suppliers, some SMETS1 meters Octopus will accept.

2) Not all EV chargers are born equal and able to be switched from one supplier to another to take benefit of their EV tariff.

I'm not quite sure what you're saying here, I can only really speak for Octopus and as far as I know they're the only supplier with smart EV tariffs. The Octopus situation if you want to use one of their smart tariffs like Intelligent, they need you to have either a wallbox they can control eg Ohme (and I believe ZAPPI) of a vehicle that they can control (more vehicles added weekly).
On intelligent you get 6 hours scheduled off peak at 7.5p plus other sessions during the peak times also at 7.5p under their control. I plug my car in during the day, within a couple of minutes Octopus have set a schedule, that sometimes includes typically mid morning, mid afternoon and early evening sessions. This enables them to efficiently balance the grid etc.
From any other point of view wallboxes can be moved between houses and between energy suppliers.

The company I got my quote from refused to connect up the EPS on the GivEnergy battery as they said it could potentially cause problems. They wouldn’t even attach a single 3pin socket to the battery for use during a power cut

They would be sent packing, thats ridiculous stance by them. The EPS doesnt add any greater load than under normal operation, it simply is an isolated supply from your main power to ensure safety of linesman working on the supply network.

 

[smokie]

£540 a month seems a helluva lot unless you are using it for heating. My most expensive month was December at £138, which cost me an average of 18.45p a unit on Octopus Go.

Of course the maths do look very good now but, as I mentioned somewhere else yesterday, if electricity rates fall significantly it would suddenly extend the payback - though in your case, especially with your home brew batteries and high usage, you're sitting quite pretty wrt payback.

As an aside, one of the problems with managing to hang into a cheap service or tariff is the cost appears to absolutely shoot up when it runs out. In theory I have a similar situation imminently with my Virgin TV/internet service. I managed to negotiate it down from a proposed £70 is a month to £44 for 18 months, and get very pleased with myself. They've now told me when it runs out (June I think) it will be going up to around £80. So on the face of it it's nearly doubling but the other view would be that I've had a very cheap 18m, and now it's back to normal. Of course, I am hoping to negotiate it down, but all these calls I have to do every year (house/car insurance work the same way) are getting a bit tedious

The Octopus Go tariff is an EV tariff but doesn't require any special EVSE - simply a SMETS2 smart meter. When I joined Octopus they put SMETS1 meters in and have since been able to upgrade them OTA to SMETS2.

 

[Hotlush]

If you're planning on moving in the next few years I wouldn't bother with a physical installation. It sounds like a share in something like Ripple would suit you better; Join Ripple and save on your bills

I have a neighbour and another family friend that have both sold houses with solar panels on. The houses were down valued due to the solar install. The agent said people prefer to buy without solar and then have it fitted themselves.

Seems madness to be but I can almost understand the buyers point of view.

If they've got a roof rental style install that makes sense as you're buying out the contract too.

A privately installed system should add value.

 

[johnb80]

£540 a month seems a helluva lot unless you are using it for heating. My most expensive month was December at £138, which cost me an average of 18.45p a unit on Octopus Go.

Yes we are high users, 2 x EV and Air conditioning / heat pump etc.

Of course the maths do look very good now but, as I mentioned somewhere else yesterday, if electricity rates fall significantly it would suddenly extend the payback - though in your case, especially with your home brew batteries and high usage, you're sitting quite pretty wrt payback.

It's widely accepted that prices wont go back to where they were. I used to be on 5p / 13.9p with Octopus GO, gas was 2.93p, those days are gone and wont be back.

As an aside, one of the problems with managing to hang into a cheap service or tariff is the cost appears to absolutely shoot up when it runs out. In theory I have a similar situation imminently with my Virgin TV/internet service. I managed to negotiate it down from a proposed £70 is a month to £44 for 18 months, and get very pleased with myself. They've now told me when it runs out (June I think) it will be going up to around £80. So on the face of it it's nearly doubling but the other view would be that I've had a very cheap 18m, and now it's back to normal. Of course, I am hoping to negotiate it down, but all these calls I have to do every year (house/car insurance work the same way) are getting a bit tedious

Agreed, I ditched Sky and went freesat, I also installed a PLEX server for all of our viewing needs and more. net cost of that is £0

The Octopus Go tariff is an EV tariff but doesn't require any special EVSE - simply a SMETS2 smart meter. When I joined Octopus they put SMETS1 meters in and have since been able to upgrade them OTA to SMETS2.

When i went to Octopus I had a SMETS1 meter that they could read, I dont thin upgrading SMETS1 to 2 is possible, it's more than firmware AFAIK. The SMETS1 they could read was made by Secure.

 

[DBedford]

Thank you for all for your very constructive comments. ??

With our age, relatively low consumption, electricity prices coming down slightly, coupled with the projected payback period we will stick with British Gas.

 

[smokie]

Pretty sure my Octopus-installed SMETS1 are Secure Liberty 100s, which they upgraded OTA.

My gas today is 3.58p (Octopus tracker tariff), which isn't so far off 2021 rates. My "problem" is I'm not using any (solar diverter to immersion and no heating).

If they ever decouple electricity tariffs from gas (which there are plans to do) then it could bring a fairly reasonable drop to electricity, although I do think the days of really cheap fuel have gone.

Aside - I've looked at most of the free options for TV and I think I could live with Plex, Freesat or Firestrick but TiVo is so ingrained for us ( - I had series 1 Thomson TiVo years before Virgin grabbed it) that we'll stick with it, within reason. For my £44 I'm getting 250Gb internet, TV with TIVo and a landline (which I don't use). Without looking too hard, a lesser internet alone would cost me at least £30.

 

[Gadget Geek]

Just as a point of interest, I just checked the national grid (GB Fuel type power generation production), and the greatest part of our grid at the moment is from solar at 23%.

 

[Gomev]

Just as a point of interest, I just checked the national grid (GB Fuel type power generation production), and the greatest part of our grid at the moment is from solar at 23%.

Indeed, I haven't looked for a while, quite impressive with the solar as there is no sunshine here or wind.
We are importing a lot though

 

[DBedford]

The following spreadsheet aid is taken from ‘Gary Does Solar’ on You Tube :

Daily Solar Modelling Utility

Worth a look, if your looking into solar and a home battery.

 

[fshuk1]

Oh Plenty to get my teeth into here....

On people liking or not liking solar panels it could depend on whether they are seen from the streets or not. If the panels are on the front of the house you really need to be committed to the eco-life-style to buy a new house with panels. In the back then you can charge more.

On panels+batteries or Batteries I would say with batteries alone and octopus intelligent you are paying 7.5ppkwh. So then do you calculations, see what the cost of panels payback period is, in going from 7.5p to zero. I will be doing the batteries first and wait for better panels.

As for buying shares in wind farms. Don't. The cost of electricity is generation+transmission. These schemes pay you a small amount for generation when you query why so little the answer is that a big chunk of the price you pay is for transmission. So, for me, the answer is put the money towards solar on your own house and then what you generate will reduce the cost of your electricity including transmission.

 

[johnb80]

Oh Plenty to get my teeth into here....

On people liking or not liking solar panels it could depend on whether they are seen from the streets or not. If the panels are on the front of the house you really need to be committed to the eco-life-style to buy a new house with panels. In the back then you can charge more.

I dont particularly like solar panels but I cant see mine when I'm in my house! There are quite a few panels available now that are physically bigger than previous ones and are all black rather than having the anodised aluminium frame, these IMHO look much better.

On panels+batteries or Batteries I would say with batteries alone and octopus intelligent you are paying 7.5ppkwh. So then do you calculations, see what the cost of panels payback period is, in going from 7.5p to zero. I will be doing the batteries first and wait for better panels.

Better panels are available now but all of them are relatively inefficient. Batteries are easy to calculate the savings. In my case 21kWh of storage at a saving of £6.53 per day, £2382 per year. My Solar PV over the last 12 months has generated 5100 kWh of electricity, taking an average of 30p kWh that amounts to £1530.

So with the benefit of hindsight is it worth it? I have to say yes. The Solar PV and 7kWh battery system cost just under £12k to install, I took out a loan to cover it which costs me £202 per month. The savings from the energy generated and stored from this system more than covers the loan cost. In reality we havent saved any money by having this system, just invested it in our property as opposed to paying it to an energy company. Octopus were increasing our monthly direct debit from £170 to £530 when our GO tariff ended a year ago, using historic data that should have been £440 assuming the same use of energy. Our actual monthly payment has gone down from £170 to £155. So the system has reduced our monthly cost for sure. I added another battery and inverter (DIY) to enable us to stay off peak rate energy throughout wintertime when solar generation is poor. This 14 kWh battery cost just under £4200 to make and savings are good in comparison to the solar PV. This saves £1600 per year giving a break even point of 2.7 years, it is a great investment. It is possible with other tariffs such as FLUX to actually earn money from a battery like this, charging up when energy is cheap and exporting to the grid when prices are at a premium, I havent gone this route yet.

As for buying shares in wind farms. Don't. The cost of electricity is generation+transmission. These schemes pay you a small amount for generation when you query why so little the answer is that a big chunk of the price you pay is for transmission.

All very true, Octopus Fan Club is worth a look, they get groups of interested parties together and build a turbine in your locality with some pretty good results.

So, for me, the answer is put the money towards solar on your own house and then what you generate will reduce the cost of your electricity including transmission.

I pretty much agree, if I was doing it all again, I would seriously consider a battery only system, leaving out the solar PV which is very expensive in terms of costs saved although, there is a great deal of smugness value when driving around having charged the car from sunlight!

 

[GaryMG4]

Our Solar came free with the house, installed only 6 months or so before the couple split up and sold up. We generate 3200 KwH a year, which equates to our annual usage. Due to the timing of installation we get feed in Tarif payments of around £800 last year. I've been considering battery storage but I think it would constitute a major change which would take us out of the FIT scheme, so instead I've got an MG4 (for a whole week now) so now I have to decide do I put the washing machine/dishwasher on or top the car up! And yes there is a certain amount of smugness driving around powered by sunshine.

 

[DBedford]

With your low usage, you would probably benefit from running items upto 2.5kW off the car via the V2L adapter with an off peak tariff to charge back up.

Edit: What items do you run regularly and have a look at their labels to see the poweer consumption. The V2L adapter will happily run a kettle, microwave, toaster, etc. (There are a couple of threads on V2L where people are doing this).

I don’t normally make toast after midnight ?

 

[smokie]

I've been considering battery storage but I think it would constitute a major change which would take us out of the FIT scheme

I've looked at batteries, alomst def not going for it now, but I hadn't realised it meant you'd lose your FIT payments - presume the early Government ones? Def not going for it in that case, I get about £2k p.a. tax free!

 

[johnb80]

I've looked at batteries, alomst def not going for it now, but I hadn't realised it meant you'd lose your FIT payments - presume the early Government ones? Def not going for it in that case, I get about £2k p.a. tax free!

If you installed an AC coupled battery, it would not affect your FIT contract.

 

[GaryMG4]

If you installed an AC coupled battery, it would not affect your FIT contract.

that's interesting, when I looked at the idea I read that ANY change to the system would end the FIT contract, but thinking about it you can install a battery system without solar. Perhaps I should investigate further.

 

[johnb80]

that's interesting, when I looked at the idea I read that ANY change to the system would end the FIT contract, but thinking about it you can install a battery system without solar. Perhaps I should investigate further.

Think of an AC coupled battery as an appliance that you connect to your electrical system like an immersion heater or electric shower, thats essentially what it is. It makes no difference at all to the FIT, it's not directly connected to it in any way.

Have look here, some info about AC/DC coupling and FIT.

Solar Battery Storage | A Comprehensive Guide - Atlantic Renewables

Unlock the power of solar battery storage with our website. Gain insights, explore options, and take control of your energy consumption for a greener tomorrow.

www.atlanticrenewables.co.uk

 

[GaryMG4]

Think of an AC coupled battery as an appliance that you connect to your electrical system like an immersion heater or electric shower, thats essentially what it is. It makes no difference at all to the FIT, it's not directly connected to it in any way.

Have look here, some info about AC/DC coupling and FIT.

Solar Battery Storage | A Comprehensive Guide - Atlantic Renewables

Unlock the power of solar battery storage with our website. Gain insights, explore options, and take control of your energy consumption for a greener tomorrow.

www.atlanticrenewables.co.uk

Thanks for the info, I'll investigate this further as it looks like a viable option.