Octopus agile/PV/Home battery/EV

JohnJ_3

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)

silverwhistle

JohnJ_3 said:

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

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

It does make sense! I have no battery and am on Intelligent Octopus, but noticed that Agile is beginning to be better value again: I was on it before.

PS: don't forget the Present Tense Third Person Singular 's'..  Sorry, ex-teacher of English.. :-)

badger09

@JohnJ_3
Impressive, though some has gone over my head😊
We’re considering a hybrid as our next (& probably last) car & also whether solar panels make economic sense. 

May I ask where are you located, what the approx cost was, how you chose the installer, and whether you did any of the installation yourself. 

Cheers

matt_drummer

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.

badger09

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.

Thanks. At the moment it’s all just pondering and I doubt the ROI on solar would be sufficient. 

[Deleted User]

OP - has your very clever son looked at Octopus' Flux tariff for the spring to autumn period? I am now on zero Grid import and I am being paid up to 38p/kWh for export.

JohnJ_3

badger09 said:

@JohnJ_3
Impressive, though some has gone over my head😊
We’re considering a hybrid as our next (& probably last) car & also whether solar panels make economic sense. 

May I ask where are you located, what the approx cost was, how you chose the installer, and whether you did any of the installation yourself. 

Cheers

hi
i believe PV panels do make financial sense as long as you do your homework well. Also providing you are intending to stay in your house for many years although im sure you will get your money back when selling your house with PV already set up.
Ideally you need to have south facing roof and depending on size of your house/roof and your family usage that then determines the amount of panels. The panels them selves are cheap (£200 odd each) its the other bits like scaffolding hire, invertor  plus other bits and of course labour cost.  We are located in Milton Keynes and we have paid a year ago 6.8k for 10x400w panels, invertor and at the time 1x6.5kw growatt battery. 
Unfortunately you cannot do the installation your self as in order to connect your PV to the grid you have to be MCS approved installer. I think MCS is little bit of a scam which is pushing the price up. From what i can gather any qualified electrician is fully capable to connect it and submit the form to your local grid company.
I did some things myself. Im plumber by trade but i have renovated many properties including mine so i have prepared it all like lifting up the floorboards for the cables from the panels and the battery can go directly into my fusebox etc... small things but makes the their work easier and of course cheaper for me as long as its done before they come or they may charge you for delays as any trader will do.
To be honest i do not know much about hybrid cars but to me they sound too complicated. You have to maintain the engine as well as the battery parts.... long term i cant see it as viable... but im not an expert.
hope this helps and any other questions or suggestions please fell free. 

JohnJ_3

[Deleted User] said:

OP - has your very clever son looked at Octopus' Flux tariff for the spring to autumn period? I am now on zero Grid import and I am being paid up to 38p/kWh for export.

hi dolor
we have looked at Flux and we have worked out that we are better off with agile but it was marginal... i suppose it really depending on set up and individual family daily usage.

matt_drummer

JohnJ_3 said:

To be honest i do not know much about hybrid cars but to me they sound too complicated. You have to maintain the engine as well as the battery parts.... long term i cant see it as viable... but im not an expert.
hope this helps and any other questions or suggestions please fell free. 

They are the worst of both worlds!

A petrol car carrying around batteries, or an electric car car with mediocre pure electric performance and range plus batteries that are too small.

Basically, these batteries last a number of charge cycles, if you are charging every day compared to once a week for a full bev, the battery is going to last one seventh of the time it would in a full electric car.

It gets worse, as the battery is smaller in a hybrid, the power drawn from it is a much bigger proportion of the total energy available. Batteries in hybrids have a hard time and I would expect them to last about 10% of the time that a battery would last in a full electric vehicle covering the same mileage.

nologo

You can't charge hybrid batteries with any kind of electricity, although some hybrids come with an additional battery that can be charged but only gives a modest range ( about 20 miles) IE Toyota prius plug in, which is even more expensive to buy.
Regards
nologo

matt_drummer

nologo said:

You can't charge hybrid batteries with any kind of electricity, although some hybrids come with an additional battery that can be charged but only gives a modest range ( about 20 miles) IE Toyota prius plug in, which is even more expensive to buy.
Regards
nologo

You can charge plug in hybrids.

You are talking about `mild hybrids' that just use recovered energy from deceleration to charge a small battery to boost acceleration.