Home Storage Battery

[Deleted member 2439]

Just as a matter of interest, how many panels does that equate to?

I've had solar for 10 years this coming October (paid for itself in FIT and reduced bills about 18 months ago. It consists of 16 panels and was originally 3.8 KWh south facing. Efficiency now is estimated as 80 - 90,% of it's original efficiency.

Just curious if your yield is due more panels or better technology panels.

32. It’s actually 8.8 kWh, gross, limited to 7kW Nett for DNO reasons.

16 original 250 watt Panasonics - which have been in for 10 years and I have a FiT on . Chosen to be the highest quality I could get at the time as I’m glad I did spend the extra as there has been no loss of power over the years. They were joined by a second system a couple of years ago made up of QCells 300 watt panels. No FiT on this system, but it all adds to the power available for the house, car and battery charging.

Cheers

 

[Rob Smart]

I’ve ordered a 4.2kw solar & 7.2kw battery system from Moixa for just over £9k fully installed. Picked Moixa as their system is a smart battery and they pay you to use it (even though most users have never had system used) and if you do this they also extend warranty of battery and inverter for as long as your with them. They do a battery only system too (bit like Tesla power wall).

I calculated a battery only solution would reduce my electricity bills by at least 75%. I only went solar + battery when I looked at funding as I can get 0% finance for both in Scotland, but would have had to pay for battery myself.

Moixa battery alone solution - 7.2kw battery £5,250 Inc vat and install, (9.6kw for £6,250). Mention me as a referal and you should get £200 off these prices.

Homepage - Moixa | Home Energy Storage | Smart Energy Management

Moixa is the UK’s leading smart battery company. We develop our Smart Battery hardware and GridShare software to facilitate smart energy storage and sharing.

www.moixa.com

I had a Moixa 4.0kWp solar and 3.0 kWh battery installed 3 years ago, for abour £9,500, so battery prices have dropped a bit. what they didn't tell me was that to maintain battery life they only allowed discharge to 20% , so I only got 2.4 kWh maximum from the battery each discharge, and that the charging and discharging losses are about 10% each way (invertor losses). The solar panels are still performing very well and as expected.

As my average daily usage was 12kWh, an effective 2.4kWh battery didn't really do much, so as I had bought some Tesla chares which went up a lot in value, I bought a 13.5kWh Tesla Powerwall which serves my needs much better.

My lesson from this is that in calculating potential savings, use the "available battery" figure not the "gross battery" figure, and also allow for charge/discharge losses which is about 10% each way for most battery systems.

 

[Mihir]

Here's my setup:

10x395W solar panels that gives me 3.95kW(almost 4kW solar) with a 2.4x2 = 4.8kWh pylontech battery storage with a 3.6kW Lux inverter.

I am on an Octopus Go Faster tariff that gives me 5 hours of cheap electricity @8.25p between 9.30pm-2.30am and 30.23p the rest of the day. Octopus Go gives us a fixed 4 hour slot between 12.30am-4.30am at @7.5p. But Go Faster lets us choose any 5 hours slot starting 9.30pm and ending no later than 5.30am.

What I do is fill up the 4.8 battery during the cheap night time. And the battery along with the solar powers my house almost the entire day. There are rarely instances where I take energy from the grid except between 9.30pm-2.30am when I charge my car and fill up the battery.

With the Lux Inverter app, I can set the times when I want the battery to be charged and when I want it to discharge. I am sure it must be the same with other products too. So I charge up the battery for 1 hour between 9.30pm-10.30 and that is enough for the house to be powered on battery between 10.30pm-1.30am. I charge it again between 1.30am-2.30am(the last cheap electricity slot) but only start discharging at 5.30am. The reason for this is between 2.30am-5.30 am we are all sleeping with hardly any electricals running(except for fridge, internet and other internet connected smart devices like ring alarm etc, doorbells etc) and I dont mind the 30.23p charge at this time. This saves the battery storage too from discharging. Between 5.30am-8am ish, battery powers the house and once solar starts at around 8am ish in jan/feb, its a combination of solar and battery or just solar that powers the house entire day. When my usage is lower than what solar generates, the solar charges the battery. So by the time it start getting dark around 4pmish, my battery is almost at 100% and then the entire evening till 9.30pm the house is powered by the battery. I do look at the battery % and then decide the times to charge it up again after 9.30pm. If its less than 30%, I charge it up at 9.30pm(when cheap electricity starts) or move it to say 10.30 or even 11pm if I have enough battery to power the house after 9.30pm too.

So in a nut shell, my grid usage is limited to between 9.30pm-5.30am of which I have cheap electricity between 9.30pm-2.30am. I have seen my outgoings and its a lot of saving with this arrangement. I used to be paying approx £75 a month on electricity and now going by the setup, it will be less than £25 a month(not factoring ev charging for like to like comparison)

Here are some of the charts for better understanding:

This is the live usage at 10.53am on 7th Feb. As you can see, right now solar is powering the house and also filling up the battery which is at 88% already.
We can also see how much of grid usage I've had(red line). After 5.30am its 0.

This is the chart from yesterday:

Grid usage is only at night. The entire day was powered by battery+solar. It was a rainy day yesterday but yet, I barely used anything from the grid. Started charging up the battery after 11pm.

I got to this setup only after I swtiched to Octopus Go Faster after 25th of Jan. So its been about 2 weeks now. My solar and battery was installed in mid December

Here is my usage in Dec without Octopus Go Faster. Solar + Battery(installed and setup on 16th Dec) did not make a massive difference as I was not using the setup correctly initially and very low 'bright' hours in December.

Here was my usage in Jan:

We can already see the usage going down. I switched to Octopus Go Faster in late Jan(25th). We can see the usage going down already towards the end of the month and whatever we see here is cheap electricity!

And this is the first week of Feb:

Everything we see here is cheap electricity. Very little of peak electricity(2.30am-5.30am everyday).
Don't be alarmed by the 12kwh usage on the 5th. Thats when I charged my ZS EV but all of it with cheap electricity times.

Here is another chart of what I paid on the 5th Feb:

So for the 12kWh energy I used to charge the car(65%-100%) and power my house, it cost me £1.29 including daily standing charge! Bear in mind this is the cost until 12am. 12am-2.30am would be in the next day's usage.

So in a nut shell, if we get our setup right with cheap electricity pricing that can be used to power the battery and the car, we can still save substantially! The reason I chose Go Faster to start at 9.30pm is we can schedule electricals like the dishwasher and/or washing machines to start at 9.30pm and they are finished before we go to sleep! We are 2 people working from home full day with multiple monitors and laptops on the entire day. We have gaming setup as well at home and have many smart devices that work on electricity and it feels like after doing a bit of R&D and few trial and errors I've got the setup right. Time will tell!

I am already thinking of adding another 2.4kWh battery to my system. Pylontech are modular. One can keep adding multiples of 2.4. This will bring down my grid usage even further down! Rememeber I am still using the grid at peak rate between 2.30am-5.30am!

The only point that we need to be aware of with cheaper electricity and solar and/or battery setup is that we cannot sell any energy back to the grid. We can export back to the grid but energy companies would not pay back anything.(They wouldn't allow us to buy at 8.25p and sell at 5.5p!). This is another reason I was thinking of adding another 2.4kWh battery.

I hope this is useful. I understand its been a long explanation but I think if we understood this correct, this setup can help everyone save a lot! EVMan videos on YouTube has helped me a lot to understand and his videos are indeed quite resourceful.

 

[biffo]

Not sure if anyone has mentioned previously, but the The EV Puzzle YouTube channel has a lot of good information too

https://www.youtube.com/c/TheEVPuzzle/videos

 

[Fluffykins]

Here's my setup:

What was the cost of the initial system and how much will you be paying for the battery upgrade?

 

[Mihir]

What was the cost of the initial system and how much will you be paying for the battery upgrade?

I paid £6200 for the Solar+4.8kWh battery storage setup. I've been quoted £1000 for an additional 2.4kWh battery. Hope this helps!

 

[Fluffykins]

I paid £6200 for the Solar+4.8kWh battery storage setup. I've been quoted £1000 for an additional 2.4kWh battery. Hope this helps!

If you're saving fifty quid a month, that's 600 a year, so payback time is a tad under 11 years.

 

[Mihir]

If you're saving fifty quid a month, that's 600 a year, so payback time is a tad under 11 years.

I totally agree on the payback! But this setup brings up the valuation of my house too(I was told by the estate agent with whom I bought the house)! If in future for whatever reason if I were to sell the house (before the payback time), I am bound to recover more than the cost of what I've invested in the setup and in the meantime it also offers me some savings year on year. If I did end up staying over 10 years, it would anyway pay me back. IMO it's about what works best individually. It is a long term investment which pays back in years but it's not going to cause any financial burden should one decide to move on before the payback period. The solar+battery setup will bring in addtional value to the property.

 

[enjoylife]

To all the good solar PV people, some advice needed:

Do you reckon bird protection important and needed in the UK? And if yes, what kind of bird protection system have got installed and what were approx costs?

We live in Center of the town but do get some birds around summer time hence checking.

 

[PAULinTHAILAND]

I didn't see this thread so posted about my solar and battery setup in General Chat Forum

mgevs.com/threads/solar-and-evs

 

[Gadget Geek]

To all the good solar PV people, some advice needed:

Do you reckon bird protection important and needed in the UK? And if yes, what kind of bird protection system have got installed and what were approx costs?

We live in Center of the town but do get some birds around summer time hence checking.

When my system failed 2 years ago, an electrician went up the ladder and found pidgeons nesting under the panels!
The guano is acidic and eats away at the connections. He re-did all the connections and installed chicken wire netting around the perimeter.
£450 for scaffolding, £500 for rewiring, cleaning panels and netting.

 

[Barrie]

I totally agree on the payback! But this setup brings up the valuation of my house too(I was told by the estate agent with whom I bought the house)! If in future for whatever reason if I were to sell the house (before the payback time), I am bound to recover more than the cost of what I've invested in the setup and in the meantime it also offers me some savings year on year. If I did end up staying over 10 years, it would anyway pay me back. IMO it's about what works best individually. It is a long term investment which pays back in years but it's not going to cause any financial burden should one decide to move on before the payback period. The solar+battery setup will bring in addtional value to the property.

Plus you are not at the mercy of the ever increasing charges and power outages. Its like having your own gas station at home.

 

[Mihir]

Here's my setup:

10x395W solar panels that gives me 3.95kW(almost 4kW solar) with a 2.4x2 = 4.8kWh pylontech battery storage with a 3.6kW Lux inverter.

I am on an Octopus Go Faster tariff that gives me 5 hours of cheap electricity @8.25p between 9.30pm-2.30am and 30.23p the rest of the day. Octopus Go gives us a fixed 4 hour slot between 12.30am-4.30am at @7.5p. But Go Faster lets us choose any 5 hours slot starting 9.30pm and ending no later than 5.30am.

What I do is fill up the 4.8 battery during the cheap night time. And the battery along with the solar powers my house almost the entire day. There are rarely instances where I take energy from the grid except between 9.30pm-2.30am when I charge my car and fill up the battery.

With the Lux Inverter app, I can set the times when I want the battery to be charged and when I want it to discharge. I am sure it must be the same with other products too. So I charge up the battery for 1 hour between 9.30pm-10.30 and that is enough for the house to be powered on battery between 10.30pm-1.30am. I charge it again between 1.30am-2.30am(the last cheap electricity slot) but only start discharging at 5.30am. The reason for this is between 2.30am-5.30 am we are all sleeping with hardly any electricals running(except for fridge, internet and other internet connected smart devices like ring alarm etc, doorbells etc) and I dont mind the 30.23p charge at this time. This saves the battery storage too from discharging. Between 5.30am-8am ish, battery powers the house and once solar starts at around 8am ish in jan/feb, its a combination of solar and battery or just solar that powers the house entire day. When my usage is lower than what solar generates, the solar charges the battery. So by the time it start getting dark around 4pmish, my battery is almost at 100% and then the entire evening till 9.30pm the house is powered by the battery. I do look at the battery % and then decide the times to charge it up again after 9.30pm. If its less than 30%, I charge it up at 9.30pm(when cheap electricity starts) or move it to say 10.30 or even 11pm if I have enough battery to power the house after 9.30pm too.

So in a nut shell, my grid usage is limited to between 9.30pm-5.30am of which I have cheap electricity between 9.30pm-2.30am. I have seen my outgoings and its a lot of saving with this arrangement. I used to be paying approx £75 a month on electricity and now going by the setup, it will be less than £25 a month(not factoring ev charging for like to like comparison)

Here are some of the charts for better understanding:
View attachment 6805

This is the live usage at 10.53am on 7th Feb. As you can see, right now solar is powering the house and also filling up the battery which is at 88% already.
We can also see how much of grid usage I've had(red line). After 5.30am its 0.

This is the chart from yesterday:
View attachment 6806

Grid usage is only at night. The entire day was powered by battery+solar. It was a rainy day yesterday but yet, I barely used anything from the grid. Started charging up the battery after 11pm.

I got to this setup only after I swtiched to Octopus Go Faster after 25th of Jan. So its been about 2 weeks now. My solar and battery was installed in mid December

Here is my usage in Dec without Octopus Go Faster. Solar + Battery(installed and setup on 16th Dec) did not make a massive difference as I was not using the setup correctly initially and very low 'bright' hours in December.
View attachment 6807

Here was my usage in Jan:
View attachment 6808
We can already see the usage going down. I switched to Octopus Go Faster in late Jan(25th). We can see the usage going down already towards the end of the month and whatever we see here is cheap electricity!

And this is the first week of Feb:
View attachment 6809
Everything we see here is cheap electricity. Very little of peak electricity(2.30am-5.30am everyday).
Don't be alarmed by the 12kwh usage on the 5th. Thats when I charged my ZS EV but all of it with cheap electricity times.

Here is another chart of what I paid on the 5th Feb:

View attachment 6810
So for the 12kWh energy I used to charge the car(65%-100%) and power my house, it cost me £1.29 including daily standing charge! Bear in mind this is the cost until 12am. 12am-2.30am would be in the next day's usage.

So in a nut shell, if we get our setup right with cheap electricity pricing that can be used to power the battery and the car, we can still save substantially! The reason I chose Go Faster to start at 9.30pm is we can schedule electricals like the dishwasher and/or washing machines to start at 9.30pm and they are finished before we go to sleep! We are 2 people working from home full day with multiple monitors and laptops on the entire day. We have gaming setup as well at home and have many smart devices that work on electricity and it feels like after doing a bit of R&D and few trial and errors I've got the setup right. Time will tell!

I am already thinking of adding another 2.4kWh battery to my system. Pylontech are modular. One can keep adding multiples of 2.4. This will bring down my grid usage even further down! Rememeber I am still using the grid at peak rate between 2.30am-5.30am!

The only point that we need to be aware of with cheaper electricity and solar and/or battery setup is that we cannot sell any energy back to the grid. We can export back to the grid but energy companies would not pay back anything.(They wouldn't allow us to buy at 8.25p and sell at 5.5p!). This is another reason I was thinking of adding another 2.4kWh battery.

I hope this is useful. I understand its been a long explanation but I think if we understood this correct, this setup can help everyone save a lot! EVMan videos on YouTube has helped me a lot to understand and his videos are indeed quite resourceful.

For the benefit of everyone, adding a screenshot of what I've been charged for 1 week of electricity which includes normal day to day use + one EV charge from 65% - 100% with my current setup in the last 1 week :

 

[Deleted member 2439]

Here's my setup:

10x395W solar panels that gives me 3.95kW(almost 4kW solar) with a 2.4x2 = 4.8kWh pylontech battery storage with a 3.6kW Lux inverter.

I am on an Octopus Go Faster tariff that gives me 5 hours of cheap electricity @8.25p between 9.30pm-2.30am and 30.23p the rest of the day. Octopus Go gives us a fixed 4 hour slot between 12.30am-4.30am at @7.5p. But Go Faster lets us choose any 5 hours slot starting 9.30pm and ending no later than 5.30am.

What I do is fill up the 4.8 battery during the cheap night time. And the battery along with the solar powers my house almost the entire day. There are rarely instances where I take energy from the grid except between 9.30pm-2.30am when I charge my car and fill up the battery.

With the Lux Inverter app, I can set the times when I want the battery to be charged and when I want it to discharge. I am sure it must be the same with other products too. So I charge up the battery for 1 hour between 9.30pm-10.30 and that is enough for the house to be powered on battery between 10.30pm-1.30am. I charge it again between 1.30am-2.30am(the last cheap electricity slot) but only start discharging at 5.30am. The reason for this is between 2.30am-5.30 am we are all sleeping with hardly any electricals running(except for fridge, internet and other internet connected smart devices like ring alarm etc, doorbells etc) and I dont mind the 30.23p charge at this time. This saves the battery storage too from discharging. Between 5.30am-8am ish, battery powers the house and once solar starts at around 8am ish in jan/feb, its a combination of solar and battery or just solar that powers the house entire day. When my usage is lower than what solar generates, the solar charges the battery. So by the time it start getting dark around 4pmish, my battery is almost at 100% and then the entire evening till 9.30pm the house is powered by the battery. I do look at the battery % and then decide the times to charge it up again after 9.30pm. If its less than 30%, I charge it up at 9.30pm(when cheap electricity starts) or move it to say 10.30 or even 11pm if I have enough battery to power the house after 9.30pm too.

So in a nut shell, my grid usage is limited to between 9.30pm-5.30am of which I have cheap electricity between 9.30pm-2.30am. I have seen my outgoings and its a lot of saving with this arrangement. I used to be paying approx £75 a month on electricity and now going by the setup, it will be less than £25 a month(not factoring ev charging for like to like comparison)

Here are some of the charts for better understanding:
View attachment 6805

This is the live usage at 10.53am on 7th Feb. As you can see, right now solar is powering the house and also filling up the battery which is at 88% already.
We can also see how much of grid usage I've had(red line). After 5.30am its 0.

This is the chart from yesterday:
View attachment 6806

Grid usage is only at night. The entire day was powered by battery+solar. It was a rainy day yesterday but yet, I barely used anything from the grid. Started charging up the battery after 11pm.

I got to this setup only after I swtiched to Octopus Go Faster after 25th of Jan. So its been about 2 weeks now. My solar and battery was installed in mid December

Here is my usage in Dec without Octopus Go Faster. Solar + Battery(installed and setup on 16th Dec) did not make a massive difference as I was not using the setup correctly initially and very low 'bright' hours in December.
View attachment 6807

Here was my usage in Jan:
View attachment 6808
We can already see the usage going down. I switched to Octopus Go Faster in late Jan(25th). We can see the usage going down already towards the end of the month and whatever we see here is cheap electricity!

And this is the first week of Feb:
View attachment 6809
Everything we see here is cheap electricity. Very little of peak electricity(2.30am-5.30am everyday).
Don't be alarmed by the 12kwh usage on the 5th. Thats when I charged my ZS EV but all of it with cheap electricity times.

Here is another chart of what I paid on the 5th Feb:

View attachment 6810
So for the 12kWh energy I used to charge the car(65%-100%) and power my house, it cost me £1.29 including daily standing charge! Bear in mind this is the cost until 12am. 12am-2.30am would be in the next day's usage.

So in a nut shell, if we get our setup right with cheap electricity pricing that can be used to power the battery and the car, we can still save substantially! The reason I chose Go Faster to start at 9.30pm is we can schedule electricals like the dishwasher and/or washing machines to start at 9.30pm and they are finished before we go to sleep! We are 2 people working from home full day with multiple monitors and laptops on the entire day. We have gaming setup as well at home and have many smart devices that work on electricity and it feels like after doing a bit of R&D and few trial and errors I've got the setup right. Time will tell!

I am already thinking of adding another 2.4kWh battery to my system. Pylontech are modular. One can keep adding multiples of 2.4. This will bring down my grid usage even further down! Rememeber I am still using the grid at peak rate between 2.30am-5.30am!

The only point that we need to be aware of with cheaper electricity and solar and/or battery setup is that we cannot sell any energy back to the grid. We can export back to the grid but energy companies would not pay back anything.(They wouldn't allow us to buy at 8.25p and sell at 5.5p!). This is another reason I was thinking of adding another 2.4kWh battery.

I hope this is useful. I understand its been a long explanation but I think if we understood this correct, this setup can help everyone save a lot! EVMan videos on YouTube has helped me a lot to understand and his videos are indeed quite resourceful.

Hi,

good write up. A similar installation to mine, with the following differences …. I have 8.8kW (gross, 7kW nett) solar with 19.2kWh of battery storage. That’s 8 Pylontech batteries and the 3.6 LuxPower charger inverter. I’m delighted with it. One small point that’s worth checking though - relating to the Lux unit. I think is 1.2 kW with one battery, 2.4 with two, only reaching the 3.6kW rate with three or more batteries. Might be worth checking - or perhaps my memory is playing tricks on me. I started with three batteries and upgraded to eight after a few months. The system performs well and apart from the app being a bit clunky and lack of documentation/user guide for all the settings, the only problem I’ve had in two years was when the Lux unit stopped working as it had failed. It was replaced under warranty.

Cheers - Rob

 

[Mihir]

Hi,

good write up. A similar installation to mine, with the following differences …. I have 8.8kW (gross, 7kW nett) solar with 19.2kWh of battery storage. That’s 8 Pylontech batteries and the 3.6 LuxPower charger inverter. I’m delighted with it. One small point that’s worth checking though - relating to the Lux unit. I think is 1.2 kW with one battery, 2.4 with two, only reaching the 3.6kW rate with three or more batteries. Might be worth checking - or perhaps my memory is playing tricks on me. I started with three batteries and upgraded to eight after a few months. The system performs well and apart from the app being a bit clunky and lack of documentation/user guide for all the settings, the only problem I’ve had in two years was when the Lux unit stopped working as it had failed. It was replaced under warranty.

Cheers - Rob

The Lux app is a bit clunky. I agree. But once we understand how it works, it becomes easier to manage. I did not quite understand the 3.6kW rate point @Lincs Robert . Do you mind eloborating a bit please so I can check?

 

[Deleted member 2439]

The Lux app is a bit clunky. I agree. But once we understand how it works, it becomes easier to manage. I did not quite understand the 3.6kW rate point @Lincs Robert . Do you mind eloborating a bit please so I can check?

Yes, no problem. Each battery can only charge, or discharge at a certain rate. A single battery can only charge/discharge @ 1.2kW. Adding another battery increases the charge rate by 1.2 to 2.4kW so the inverter is being “restricted“ by the capacity of the batteries. Adding another battery means that the batteries charge/discharge capacity is the same as the Lux unit (3.6kW). A fourth battery being added still sees the Lux unit operate at 3.6max, but the power is spread over 4 batteries rather than 3. Having 8 batteries means that the individual battery charge/discharge rates are proportionally less than a system having 3, or less, batteries. As each of the n batteries in the system is connected in parallel with the other batteries and Lux unit, the current in or out of all the batteries will be the same for each one. Hopefully that clarifids things?

Lux do an upgrade where adding a second unit gives a 7kW max charge/discharge rate.

 

[Mihir]

Yes, no problem. Each battery can only charge, or discharge at a certain rate. A single battery can only charge/discharge @ 1.2kW. Adding another battery increases the charge rate by 1.2 to 2.4kW so the inverter is being “restricted“ by the capacity of the batteries. Adding another battery means that the batteries charge/discharge capacity is the same as the Lux unit (3.6kW). A fourth battery being added still sees the Lux unit operate at 3.6max, but the power is spread over 4 batteries rather than 3. Having 8 batteries means that the individual battery charge/discharge rates are proportionally less than a system having 3, or less, batteries. As each of the n batteries in the system is connected in parallel with the other batteries and Lux unit, the current in or out of all the batteries will be the same for each one. Hopefully that clarifids things?

Lux do an upgrade where adding a second unit gives a 7kW max charge/discharge rate.

Thanks for this detailed explanation Rob.

 

[BarryH]

We were intending to have solar panels installed about April/May time but on our energy bill, its not the electric that’s the major culprit, it’s the gas! Unfortunately, I can’t drill a borehole and extract it myself! Now if that cowboy Putin can reduce the tension in Eastern Europe, open up the other gas pipe and be a good boy for once, we might see gas prices drop right down! And pigs might fly!

Take a look at "The EV Puzzel" channel on YouTube there is one of Nigel's videos in which he explored the use of electric radiators in conjunction with his solar PV and Battery Storage so that he could not use his Oil Central heating this winter. It might be worth a watch - he is very methodical in his measurement and data collection that he shares to prove or reject his hypothesis.

He has also a lot of things to say about his experience with GivEnergy, Puredrive and more recently Huawei storage systems worst and all.

 

[BarryH]

My average usage was about 8KWh per day. Standard Price per KWh was 20p so if I consumed all power at that price it would be £1.60 per day, £584 pa (plus standing charge of about 20p per day).

I sized my battery to take almost all of my load so if it charges during off-peak @ say 5p per KWh it works out at 40p per day or £146 pa (plus standing charge of about 20p per day).

There is one thing to remember though to achieve those savings you have to be careful on what you peak demand is at any time you are expecting to use your stored Kwh. So for example at the link below will show that the GivEnergy AC Coupled inverter which is rated as a 3 kW inverter can't deliver more than 2.2 kW into the house. Nigel of the YouTube channel "The EV Puzzel" did a test charging and discharging his 5. kWh GivEnergy battery. During the discharge with everything in the house turned off (other than the house alarm but including the fridge) he ran a 2 kW fan heater but anything more that took total demand over 2.2 kW then the system would buy electricity from the Grid. In other words, it wouldn't boil a kettle in normal everyday use. The other consideration is that the inverter was only 88 to 89% efficient ie it drew 2,562 watts from the battery but only delivered 2,257 watts into the house. There would also have been losses charging the battery and independent sources say alow 25% to 30% overall losses from overnight AC into the Battery and back to usable AC. So you would need to factor that into the calculation. Nigel discharged down to 4% on the 5.2 GivEnergy battery and found the available capacity was only about 4.5 kWh.

The bottom line is yes you can buy overnight on Octopus Go (I currently have it at 5p but new contracts are 7.5p) but you'll only recover 70% of what you put in overnight as useable energy the following day so Solar PV is an important element of the mix.



If you are not on Octopus already the Save on Utilities and to share £100 with me (50:50) go to: share.octopus.energy/zappy-guppy-175

 

[biffo]

Watching the EV Puzzle provides a lot of good background information - I'm considering a solar diverter for hot water such as an Eddi or Solar iBoost to supplement/replace my gas system boiler heating my hot water tank - his latest video on vertically placed panels facing East was really interesting in this respect.