Solar and house battery installation

[tsedge]

Guys, the economics vary enormously depending on the type of house, heating system and usage patterns which are hugely different - remember some people have hot tubs and pools and lots of long showers and baths and appliances and others are essentially monastic.

It is entirely possible for a given solar and battery setup to be a quick payback for one person and a losing proposition for the next.

All I know is the calculation hasn't worked out for me yet but hearing from people for whom it has is a good thing, it reminds me to check again and reassess and I have no doubt at some point it will be a no brainer to do it.

 

[johnb80]

Genuine question, how are you using quite so much electricity?

Working from home, 2 x EV, Air Conditioning and a laser cutter.

Or maybe that's a fairly normal figure but it looks horrific to me!!

Its the normal level of consumption for us.

I was also going to comment on what a good rate you have but then noticed it's 2021

Yes it was 5p / 13.2p on Octopus GO before Ukraine kicked off, happy days. I used the 2021 figures because thats the full year before I ventured into solar and batteries.

EDIT As pointed out elsewhere, and hadn't occurred to me, you probably have no gas... and are therefore heating electrically...

Sadly not, 19403 kWh gas as well.

We were using heatpumps some of time as well as gas, now we have got the solar, batteries, new heatpumps and home assistant our gas usage has plummeted, the electricity too.

My comment was not aimed at anyone person. Sorry if you feel that.

In all honesty having looked back along this thread, I cant see anyone else that has been challenged on figures for solar / battery and payback, how could it be aimed at anyone else but me? Like I said, I'm not really bothered, people can analyse figures in any which way they want, my bank balance proves my calculations are correct and it was one of the best things I have done for sure.

Guys, the economics vary enormously depending on the type of house, heating system and usage patterns which are hugely different - remember some people have hot tubs and pools and lots of long showers and baths and appliances and others are essentially monastic.

They absolutely do, so true.

It is entirely possible for a given solar and battery setup to be a quick payback for one person and a losing proposition for the next.

Totally agreed, it's just some people report 'solar you cant get your money back for at least 15 years' rather than stating in their case.

All I know is the calculation hasn't worked out for me yet but hearing from people for whom it has is a good thing, it reminds me to check again and reassess and I have no doubt at some point it will be a no brainer to do it.

The real advantage for me that has made it a lot more viable is that the big battery I have I made myself at a considerable saving and integrating it all with Home Assistant has made a huge difference to energy savings.

 

[Gomev]

A quick question that has been puzzling me regarding batteries and power cuts.

I see that in the event of a power cut not all battery storage systems take over and feed the house. So question is why not ?
When the grid is fine the batteries power the house, so why not when the grid is down?

I have seen that the batteries will power 'a' socket during a power cut if you pay extra for this or no power at all.

Can someone explain or am I reading all the information wrong ?

 

[Hotlush]

A quick question that has been puzzling me regarding batteries and power cuts.

I see that in the event of a power cut not all battery storage systems take over and feed the house. So question is why not ?
When the grid is fine the batteries power the house, so why not when the grid is down?

I have seen that the batteries will power 'a' socket during a power cut if you pay extra for this or no power at all.

Can someone explain or am I reading all the information wrong ?

Cost and safety for what, in the UK, is an infrequent and short occurrence.

Solar Back-up Batteries & Power Cuts | Solar Guide

Would a solar battery provide back-up electricity for your home during a power cut? Find out more and get free quotes for solar batteries here.

www.solarguide.co.uk

 

[Gadget Geek]

In the UK you have grid tied inverters so that if the power goes off and a workman comes to fix the cable, he isn't electrocuted by your panels or battery. You can pay for an isolator unit which cuts you off from the grid and allows the panels and batteries to safely power the house. I have a double socket which is permanently live from the battery which I can plug extension leads into to keep the fridge-freezer running and other esseential items.

 

[johnb80]

A quick question that has been puzzling me regarding batteries and power cuts.

I see that in the event of a power cut not all battery storage systems take over and feed the house. So question is why not ?
When the grid is fine the batteries power the house, so why not when the grid is down?

I have seen that the batteries will power 'a' socket during a power cut if you pay extra for this or no power at all.

Can someone explain or am I reading all the information wrong ?

The danger is that if your supply goes off for any reason your inverter will try and keep the voltage on. The power from your inverter is connected to your wiring and it's output would be fed back into the incoming supply. Any power system workers could be working on the dead side of the supply and would be in danger if your inverter had not switched off it's output.
It is possible for the inverter to continue to supply your premises during a powercut, most have an 'Emergency Power Supply' of EPS. This output is made live when the main power is removed and it will provide power from batteries and/of solar. To make this available to your premises you need a change over or generator switch. The switch disconnects your incoming supply from your fusebox and connects the EPS to the fusebox instead, you then have power. There are automatic units that will switch over on loss of grid power and switch back when grid power is restored. I have fitted one of these to my system and you are totally unaware that theres been a power outage.

 

[Gadget Geek]

The danger is that if your supply goes off for any reason your inverter will try and keep the voltage on. The power from your inverter is connected to your wiring and it's output would be fed back into the incoming supply. Any power system workers could be working on the dead side of the supply and would be in danger if your inverter had not switched off it's output.
It is possible for the inverter to continue to supply your premises during a powercut, most have an 'Emergency Power Supply' of EPS. This output is made live when the main power is removed and it will provide power from batteries and/of solar. To make this available to your premises you need a change over or generator switch. The switch disconnects your incoming supply from your fusebox and connects the EPS to the fusebox instead, you then have power. There are automatic units that will switch over on loss of grid power and switch back when grid power is restored. I have fitted one of these to my system and you are totally unaware that theres been a power outage.

I thought that's what I said.

 

[johnb80]

I thought that's what I said.

Not quite...........

 

[tsedge]

Some things are worth saying more than once and in different ways, people benefit from multiple similar perspectives because it gives credence to what is being said.

 

[johnb80]

Some things are worth saying more than once and in different ways, people benefit from multiple similar perspectives because it gives credence to what is being said.

Agreed, bullsh*t baffles brains

 

[1MGEVUSER]

How do you go about doing the DIY installation?

Is this the right order?

1) buy the battery system
2) the inverter
3) cables, breaker, override/cut off switch, CT clamp.
4)DIY install

Then:
5) get the electrician to connect a 32A armoured cable from the main board to the location of the inverter. off a sub fuse board with RCD.

6) let the electrician finish the job.

Does the DNO need to be notified?
If yes, who does this Me or the electrician?

Any other steps?

I am considering such install myself.

 

[johnb80]

How do you go about doing the DIY installation?

Is this the right order?

1) buy the battery system
2) the inverter

These two should be done together to ensure compatibility with each other. The compatibility is around the communications link between the two, it's not absolutely essential that they do talk to each other but it is helpful if they do. Fogstar do some very nice, keenly priced batteries that have multiple comms protocols built in.

3) cables, breaker, override/cut off switch, CT clamp.

The CT Clamp is often supplied with inverter, yes to all other parts.

4)DIY install

Yep, it may worthwhile having a meeting with your chosen sparkie just to confirm he's happy with your ideas with regards to installation

Then:
5) get the electrician to connect a 32A armoured cable from the main board to the location of the inverter. off a sub fuse board with RCD.

Sounds OK, technically the inverter shouldnt share an MCB in the main board, if the RCD trips the inverter can still supply power backfeeding other items. Many are connected this though.

6) let the electrician finish the job.

Yes

Does the DNO need to be notified?
If yes, who does this Me or the electrician?

Either, it's straight forward to do, forms are usually online and they just need details of parts i.e. inverter, size etc, I set my export to zero for my battery.

Any other steps?

Get yourself some facecream, your cheeks will ache with the big cheesy grin when you run 24/7 on a 7.5p tariff.

I am considering such install myself.

Go for it, do your research, there are some inverters now designed for this exact application Solax, Solar Edge and Victron spring to mind, look at 5kW or more if you can.

 

[1MGEVUSER]

That's great @johnb80, it seems easy.

 

[johnb80]

That's great @johnb80, it seems easy.

It is relatively straight forward, there are dangers there of course which you need to understand, the batteries whilst low voltage (safe) have a huge amount of energy stored in them and therefore potential hazard. The ready made batteries are all plugs and sockets so safe and easy to use. The inverter connections you do with a totally dead system, once connected to your supply by your competent person, the switch on, startup and configuration is usually simple (set the charging time, set the charging parameters eg max current), job done. Switch the kettle on and watch your smart meter not increase consumption LOL.

From the 1st Jan this year to now, I have used 4327 off peak units and 22 peak rate units of electricity. My rates were .38p peak, 0.075 off peak. A quick calculation shows (0.38-0.075)x4327=£1319 saved in 6 months. It's not quite that good because I could have got some of the power at 7.5p anyway but is a reasonable ball park figure.

 

[Gadget Geek]

It is relatively straight forward, there are dangers there of course which you need to understand, the batteries whilst low voltage (safe) have a huge amount of energy stored in them and therefore potential hazard.

Yes, it's the current that kills. 200mA will stop a heart regardless of the voltage. Static electricity which gives you a shock can be at thousands's of volts but only microamps of current.

 

[Gomev]

In the UK you have grid tied inverters so that if the power goes off and a workman comes to fix the cable, he isn't electrocuted by your panels or battery. You can pay for an isolator unit which cuts you off from the grid and allows the panels and batteries to safely power the house. I have a double socket which is permanently live from the battery which I can plug extension leads into to keep the fridge-freezer running and other esseential items.

The danger is that if your supply goes off for any reason your inverter will try and keep the voltage on. The power from your inverter is connected to your wiring and it's output would be fed back into the incoming supply. Any power system workers could be working on the dead side of the supply and would be in danger if your inverter had not switched off it's output.
It is possible for the inverter to continue to supply your premises during a powercut, most have an 'Emergency Power Supply' of EPS. This output is made live when the main power is removed and it will provide power from batteries and/of solar. To make this available to your premises you need a change over or generator switch. The switch disconnects your incoming supply from your fusebox and connects the EPS to the fusebox instead, you then have power. There are automatic units that will switch over on loss of grid power and switch back when grid power is restored. I have fitted one of these to my system and you are totally unaware that theres been a power outage.

Thank you both.
I understand the picture of the setup but not being an electrician I just needed some of the 'obvious goes without saying so never said' basics clarifying. One of which for example is, I presume the inverter is grid tied because it inverts both ways AC to DC for charging up batteries from the grid, and then DC to AC for running the house from the batteries.
I quite like @1MGEVUSER plan for partial self DIY, I'm happy to buy the bits to save a bit of dosh but would prefer a professional to put them together neatly
Can any qualified electrician do this or is there a special sub-species of them with additional know-how/certificates like EVSE installers have to have.

 

[johnb80]

Thank you both.
I understand the picture of the setup but not being an electrician I just needed some of the 'obvious goes without saying so never said' basics clarifying. One of which for example is, I presume the inverter is grid tied because it inverts both ways AC to DC for charging up batteries from the grid, and then DC to AC for running the house from the batteries.

A grid tied inverter works in conjunction with your grid supply. It monitors the AC supply and synchronises it's output to be the same frequency and in sync. It looks at your grid supply via a CT or a meter to detect import or export. If energy is coming in from the grid it will increase it's output voltage until the import stops or the capacity of the inverter is reached. If it sees export it reduces it's output voltage until the export stops. It does this at a high rate, typically 100 times per second. Thats a grid tied inverter.
There are non grid tied inverters where the grid goes into the inverter and output from inverter goes to your house. Solar and/or batteries can feed the inverter as well. The plus side of this is if the grid goes off as long as you have battery or solar the out stays on for your house, the downside is the max capacity of the inverter is the maximum your house can demand at any time, the grid cannot support the house load directly.

Most inverters used in houses are grid tied.

I quite like @1MGEVUSER plan for partial self DIY, I'm happy to buy the bits to save a bit of dosh but would prefer a professional to put them together neatly
Can any qualified electrician do this or is there a special sub-species of them with additional know-how/certificates like EVSE installers have to have.

Any half decent sparky can do this, there is only Live, Neutral and Earth to connect into the inverter via a consumer unit / fusebox, connect positive and negative to batteries and plug the CT and comms cable in.

 

[Gadget Geek]

Zac and Jessie on Now You Know channel did a video of setting up a solar system in a trailer, which would be very similar to doing the same in a house. Again, just need a qualified electrician to do the final hook up.

 

[1MGEVUSER]

Don't have that channel on my TV

From the 1st Jan this year to now, I have used 4327 off peak units and 22 peak rate units of electricity. My rates were .38p peak, 0.075 off peak. A quick calculation shows (0.38-0.075)x4327=£1319 saved in 6 months. It's not quite that good because I could have got some of the power at 7.5p anyway but is a reasonable ball park figure.

I have just joined Octopus Go. Some people suggested Octopus Intelligent but my MG ZS EV and the Easee One charger are not currently compatible with this tariff but I estimate that if I use a home battery storage, it should save me around £1100 in a year at the current Go prices. The tariff has been lowered to 30.60p /day and 9.5p /4 hours a night.

 

[Gadget Geek]

Don't have that channel on my TV

It's a YouTube channel.
,

Edit: Also if you search YouTube for "DIY solar and battery system", there are a few step by step guides.