Octopus agile/PV/Home battery/EV

donaldpage

We installed a similar set up to JohnJ_3 in February 2022 (4.8kWh peak solar panels and 13kWh batteries) and generated 4,325 kWh in the first year. With the batteries, we managed to retain and consume 3,319kWh saving us just over £1,000 based on the unit pricing through this period.
Savings this year should be even greater as we've moved to charging the batteries at night using Octopus 12p night rate and hopefully getting their 15p export rate from May (long story) . Also found out how to run the washing machine in the cheap period along with the dish washer - current estimate from Octopus is that we are paying an average rate < 20p per kWh. If we had had that last year then we would have saved an additional £450 giving us a payback of 7 years.
While I know the articles have to be conservative in their numbers, I don't see why in MES's Free Solar Panels article, Solar Energy say the batteries add another 5 to 13 years on payback. If used correctly they definitely reduce it overall.

JohnJ_3

donaldpage said:

We installed a similar set up to JohnJ_3 in February 2022 (4.8kWh peak solar panels and 13kWh batteries) and generated 4,325 kWh in the first year. With the batteries, we managed to retain and consume 3,319kWh saving us just over £1,000 based on the unit pricing through this period.
Savings this year should be even greater as we've moved to charging the batteries at night using Octopus 12p night rate and hopefully getting their 15p export rate from May (long story) . Also found out how to run the washing machine in the cheap period along with the dish washer - current estimate from Octopus is that we are paying an average rate < 20p per kWh. If we had had that last year then we would have saved an additional £450 giving us a payback of 7 years.
While I know the articles have to be conservative in their numbers, I don't see why in MES's Free Solar Panels article, Solar Energy say the batteries add another 5 to 13 years on payback. If used correctly they definitely reduce it overall.

I suppose the payback time depending on many factors such as initial cost, annual PV production and i suppose how much due diligence is one prepare to do to get most out of the investment.
It will also long term depending on where the energy prices will go from here. In theory with more and more renewables electricity prices should go lower so payback time will be longer but im sure energy companies will find an angle to keep the prices high for bigger profits to keep the shareholders happy! 

Running the EV is certainly much cheaper being on agile as long as you charge at cheap times however due to the massive initial cost of the EV im under no illusion i will never get my investment back! 

JohnJ_3

JohnJ_3 said:

We have recently made a move to jump on the electric "bandwagon" and rather than inflation eating away on our savings and decided invest in PV panels, home battery and EV in hope saving money and environment. After a year I though I will share our progress, set up and finding to help others who are trying to achieve similar.

Firstly with our set up
We have 4,1kW solar panels
13kW growatt battery (2x6.5kW)
Growatt SPH3600 invertor
Zappi EV charger
Skoda Enyaq 80

And this is how its working for us and what we have done to maximalise the investment

Our PV panels are on south facing roof and over the last 365 days has produced 4270kW. We are on Octupus agile incoming and outgoing tariff. With average price of standard fixed rate tariff is 35p per kW this would be £1.494 per annum which i think its pretty good. This does not take into an account the exported kWh.

As expected the summer is great and winter not as much. But being on octopus agile we have found that we can charge our home battery in the cheap times and use the battery in the day when sun is not shining. This way you will save even more.
The growatt invertor allows you to set up different battery charging and discharging times.
So in some instances we can charge the battery for lets say 10p per KW and sell it back to the grid between 16.00 - 19.30 for up to 20p per Kw. I know it is pennies but if you make 50p per day this way you can get even more ROI. 

The zappi EV charger does allow you to charge your EV from the excess from your PV. So if its a sunny day and PV producing lets say 3kw and home usage in the day time (when kids at school and missus working from home on computer) the usage is only 0.4kwh so the excess 2.6kw goes automatically into the EV once the home battery is full. I know 2.6kwk is not a lot but if the car is there all day you can add few kw probably enough to have day to day running around.

My son (age 16), i think computer genius, has created a small software to manage all our set up.
The software automatically monitors octupus agile incoming and outgoing price and setting up charging and discharging (home battery and EV battery) times based on average prices for the times the house battery and EV battery needs to change up to % and time required to reach this % value. So it works this way. The software will analyze the cheapest time and set charging times base on fact the EV can charge at 7.2kw (standard home charger) and home battery can charge at 3kw (SPH 3600 invertor maximum input and output).

For example:
Tomorrow's predicted incoming agile price are at 00:00     -1.1p ,     00:30     -4.4p,      01:00     -5.7p which means we will get paid for charging the car and home battery! Bargain! It is recommended to charge the EV's up to 80% to extend the lifespan of the battery however we have set it up that the system will automatically charge the car to 100% in the event the price drops below 10p per kwh. This way we will maximalise the ROI on the purchase of the car. 
The agile price are not always this low but if you monitor the prices well, you will be able to predict times and days when the prices will be low and charge your home battery and your EV accordingly. We are happy for our EV to go low on charge and wait for the best day/time to charge unless we know we are making any long journeys and then we make manual adjustment to charge the car. We are also looking to use Google maps API to predict the KW needed for our journey and charge accordingly at cheapest possible price!

The system also take data from predicted solar production based on your roof orientation and panels kw production (ours 10x400w) ( public API) to work out how much to charge home battery based on our average house usage(our around 15kw per day). So for example if the predicted solar production is over the battery capacity then we do not charge the home battery over night. Depending how much is left in the battery by the afternoon system will then discharge back to the grid between 17.00-19.30 when the outgoing agile prices are the highest up to 20p per kwh, leaving 30% in the battery to last us for the rest of the day(battery only discharges to 10% to protect the battery) 20% of 13 kw is normally plenty after the cooking times.

However if the predicted PV production is lets say only 5kw the automated system will charge the battery to supplement the PV production. This is also based on the price per kWh. ei if the agile predicted price drops below 10p per kwh then we will charge the home battery regardless as we will most probably sell it back at peak time for more.
Also in some instance the agile price is cheap between 13.00-15.00 (not quite sure why) so in this instances we charge the home battery to full and push it out again at outgoing peak times. 

We are now working on home smart phone app to monitor, view and adjust all current settings and make adjustments. I know this is very complex and very device specific set up but i hope this goes to show that anything is possible and this way you can really make saving. I would estimate that my PV/battery set up will pay for its self in about 5-6 years. Taking inflation into an account i think it is certainly one of the best long term investments you can make now days. 

So far we have been running this new automated system for about a month and still making adjustments but so far so good.

Well i hope all this makes sense and if anyone has any contributions ,any questions or suggestions please add in this forum.

Ps: Apologies for any spelling mistakes(english is not my first language)

Hello everyone
I have little time so I thought I will update my latest finding on our Solar panels/battery storage/EV/octopus agile project.
We have received our latest electricity bill for May-June and im well impressed with the results.
My import bill (excluding the outrages standing charge) is £37.25 and we have used 247.5kw(most of this is charging EV) which is then averaging (day and night) 15.05p per Kwh. Not bad at all. For the same time we have exported ( from panels and from home batteries) £28.16 worth of electricity(217Kw at average export rate of 12.96p per kWh) which then in turn means my electricity bill for home usage and charging my EV is £9 for the month!!
With average monthly electricity would be around £100 and our average monthly fuel spending around £250 we will save £350 a month. I know the winter months will be different but I would still say I can save average £250 a month which makes £3000 a year. With this my PV set up will be paid in 2.5 years!

We have produced from may to june 552kw from our 4100w PV set up.

We have found out that it is not about how much you export but when you export. The best time to export on the octopus agile is between 16.30 and 19.30. We save most of our electricity in the battery (13KW) and discharge it. Our average export rate of 12.96p per kWh!!!

Also with octopus the prices vary not only in the night but also in the day. The other day agile prices went bonkers and between 8am and 4pm we got paid up to 19p per kWh used... well rest assured i have charged my EV to 100%( i know not recommended but wont do it too often) and got my mate round with his EV to charge his. It total we have earned £5.75 from this in one day!!

My son who has now finally completed his GCSC's is working on the new version of our software managing the solar panels/invertor/battery charge and discharge time as well as best time to charge the car on Octopus agile.

I think the days of fixed tariffs are gone. Agile way is the way forward. I know most people like the certainty of fix rates and don't have the ability or time but once it all set up all we need to do is a run a script and the setup for next day is complete. Next version will be fully automated.

I hope this will be helpful for someone out there and if anyone would like to know more then please ask... happy to share and save even more! 

Alnat1

Have you considered Fixed Outgoing rather than Agile? Octopus pay 15p/kWh no matter what time you're exporting. The tariff has been beating Agile Outgoing for some time.

[Deleted User]

I suggest that you compare Agile with Flux. In June, my array generated £169 in export payments at an average rate of 26.66p/kWh. This includes battery and EV charging. My total import was 0.3kWh.

JohnJ_3

Dolor said:

I suggest that you compare Agile with Flux. In June, my array generated £169 in export payments at an average rate of 26.66p/kWh. This includes battery and EV charging. My total import was 0.3kWh.

Hi Dolor
i have been looking at the import and export rates of the flux. I would have to run the number but to me the night import rate(2-5am) of 17.69p per kWh seems bit steep i can import on agile on most night between 5p to 12p per Kwh and also in many cases i can fill the battery again in the afternoon and sell it back to the grid later in the peak. 
Also it mean with EV in 3 hour i can only charge 21kw (at 7.3kw per hour)
The peak exports rates are really impressive. We are family with kids so most usage is unfortunately in the peak times so exporting all peak times is not really an option.

How do you manage to import only 0.3kwh? That cant be per month? Whats the capacity of your home battery?

[Deleted User]

JohnJ_3 said:

Dolor said:

I suggest that you compare Agile with Flux. In June, my array generated £169 in export payments at an average rate of 26.66p/kWh. This includes battery and EV charging. My total import was 0.3kWh.

Hi Dolor
i have been looking at the import and export rates of the flux. I would have to run the number but to me the night import rate(2-5am) of 17.69p per kWh seems bit steep i can import on agile on most night between 5p to 12p per Kwh and also in many cases i can fill the battery again in the afternoon and sell it back to the grid later in the peak. 
Also it mean with EV in 3 hour i can only charge 21kw (at 7.3kw per hour)
The peak exports rates are really impressive. We are family with kids so most usage is unfortunately in the peak times so exporting all peak times is not really an option.

How do you manage to import only 0.3kwh? That cant be per month? Whats the capacity of your home battery?

Tesla Powerwall 13.5kWh. I don’t play around with it. It charges when the sun shines and I do not force battery export from 4 to 7 pm. I am normally off grid from late February until late October. I will then switch to Go or IO to charge the battery overnight. What matters to me are the overall savings not just import and export rates.

JohnJ_3

[Deleted User] said:

JohnJ_3 said:

Dolor said:

I suggest that you compare Agile with Flux. In June, my array generated £169 in export payments at an average rate of 26.66p/kWh. This includes battery and EV charging. My total import was 0.3kWh.

Hi Dolor
i have been looking at the import and export rates of the flux. I would have to run the number but to me the night import rate(2-5am) of 17.69p per kWh seems bit steep i can import on agile on most night between 5p to 12p per Kwh and also in many cases i can fill the battery again in the afternoon and sell it back to the grid later in the peak. 
Also it mean with EV in 3 hour i can only charge 21kw (at 7.3kw per hour)
The peak exports rates are really impressive. We are family with kids so most usage is unfortunately in the peak times so exporting all peak times is not really an option.

How do you manage to import only 0.3kwh? That cant be per month? Whats the capacity of your home battery?

Tesla Powerwall 13.5kWh. I don’t play around with it. It charges when the sun shines and I do not force battery export from 4 to 7 pm. I am normally off grid from late February until late October. I will then switch to Go or IO to charge the battery overnight. What matters to me are the overall savings not just import and export rates.

The tesla power wall costs absolute fortune! The ROI is not practical from my point of view. I have 2x6.5KW growatt battery costing just over 4.5k(when installed with PV so no VAT). Whats the capacity of your PV?

[Deleted User]

JohnJ_3 said:

[Deleted User] said:

JohnJ_3 said:

Dolor said:

I suggest that you compare Agile with Flux. In June, my array generated £169 in export payments at an average rate of 26.66p/kWh. This includes battery and EV charging. My total import was 0.3kWh.

Hi Dolor
i have been looking at the import and export rates of the flux. I would have to run the number but to me the night import rate(2-5am) of 17.69p per kWh seems bit steep i can import on agile on most night between 5p to 12p per Kwh and also in many cases i can fill the battery again in the afternoon and sell it back to the grid later in the peak. 
Also it mean with EV in 3 hour i can only charge 21kw (at 7.3kw per hour)
The peak exports rates are really impressive. We are family with kids so most usage is unfortunately in the peak times so exporting all peak times is not really an option.

How do you manage to import only 0.3kwh? That cant be per month? Whats the capacity of your home battery?

Tesla Powerwall 13.5kWh. I don’t play around with it. It charges when the sun shines and I do not force battery export from 4 to 7 pm. I am normally off grid from late February until late October. I will then switch to Go or IO to charge the battery overnight. What matters to me are the overall savings not just import and export rates.

The tesla power wall costs absolute fortune! The ROI is not practical from my point of view. I have 2x6.5KW growatt battery costing just over 4.5k(when installed with PV so no VAT). Whats the capacity of your PV?

Yes, a PW2 costs about £7k plus extra for a Gateway. The Gateway provides whole house islanding. I have a 6.35kWp array and I am currently looking at a break even point of 8 years. 

GerbilsNuts

matt_drummer said:

badger09 said:

@JohnJ_3

We’re considering a hybrid as our next (& probably last) car 

I would advise you to think very carefully about that.

If you intend the hybrid to be your last car and you would like to drive using battery power most of the time, you may well end up disappointed in a very short time.

Hybrid cars are not kind to their batteries and they are unlikely to last as long as you might think.

I had a plug-in hybrid (Kia Niro PHEV) for 4 years and the battery capacity hardly dropped at all in that time, giving me 36 miles on a full charge and 65mpg when on hybrid-only (i.e. minimum charge in the battery). Obviously, a PHEV is somewhat different to an HEV, and maybe HEVs are less kind to their batteries.