@transparent let's keep it simple. You're overthinking it mate! The OP here has Cosy Octopus and wants to run, for as much as possible, their future ASHP off a variable TOU tariff and leverage the advantage of the low rate periods 2x3hrs a day, Same with me. I've the same inverter, a near-identical sized 3.8kW solar array, and in my case a 10kW Grant Aerona, which never draws more than 3000W.

I've shunted 85% of my consumption to Cosy's low rate tariff. I'll never get 100% of it as the storage isn't big enough, nor is the inverter output rated. Although rated for 5kW max output, it's limited to 3kW as it's grid connected and set up for export. The OP might not want to go off grid. The SPH5000 inverter takes care of any additional power demand by drawing from mains. It all works for me. On cold days when my ASHP is working hard, and there's little or no solar generation, 11kW of useable power from 13kW of battery storage falls short and won't hold out until the next scheduled charge session, so it draws from mains. But on average 85% of my total electricity consumption for everything, ASHP included, is now on the low rate thanks to schedule charging the batteries twice a day for about 3hrs each time. That's a £500 a year electricity bill saving in my case.

If you think about the Cosy Octopus tariff, 2x3hr periods isn't long enough each day to effectively heat a house using renewable lower grade heating such as ASHPs. It's badged up as an ASHP tariff, but it's real incentive is, in common with most low rate tariffs, to move consumption away from peak times. That's where a reasonable battery storage added to a modest solar PV array can be very useful in the winter heating season.

@transparent thank you. We’re learning so much!  

And @allyfish thank you for your response.  It made me smile!

We are absorbing all the advice.  I think the interpretation offered by @allyfish  hits the mark for our level of expertise :-). We also have a small log burner and a source of wood (free apart from the effort of seasoning and splitting) so this will help.

Thanks again, we’re so glad we found this group

@morrisandcharlie let's look ahead to what's about to happen within the lifetime of your Growatt inverter, battery(ies) and the (yet to be installed) ASHP.

1: Electricity presently costs more in the regions furthest from the centre of Britain.
That's because when we relied on several dozen large power stations, it cost more to send power to those distant areas.

Now they have become the regions which are generating prolific amounts of electricity from renewable sources.
So the Distribution Network Companies now charge these regions more for a different reason...
... these remote locations are required to fund grid upgrades in order to send their energy to the areas where demand is highest (Central and South-East England)

That process started in April 2022, just at the start of the energy crisis.
Here's the BBC report of the increases in standing charges which were applied at that time:

How long do you think it will be before us West Country yokels realise the consequences of this strategy and demand that this inequality is redressed?

Or perhaps I'm over-thinking things.

2: All of the Time-of-Use tariffs being offered by Octopus are based on national statistics created by National Grid ESO.
NG-ESO look at the average supply & demand flows across Britain and use that to manage which generators should be paid to supply the grid.

That strategy pays no attention to the regional aspects of the increasingly-large renewable energy sector.
It can be blowing a gale on the north coast of Devon & Cornwall, but the time-based ToU tariffs from Octopus provide no incentive for me to use/store electricity from all those megawatts of wind turbines.

The new approach is to implement Nodal-pricing, based on the location of generation and user-demand.
I can already see how that can work.
I have live access to the (private) data used by National Grid, and I'm in good communication with engineers who are preparing the next phase of grid development.

So the present Cosy, Go and EV tariffs from Octopus will need to morph into a different strategy.
The data on which to base the next range of tariffs already exists.
Basing new capital investment on the present Cosy tariff doesn't reflect future energy scenarios.

Or perhaps I'm over-thinking things.

3: So why can't Octopus just continue to offer tariffs based on statistics from National Grid ESO?
... because their licence isn't being renewed by Ofgem this year.

The strategy and operational decision-making for all energy networks in GB is being passed into the hands of the new Independent System Operator & Planner (ISOP).

The formal Decision Notice was issued by Ofgem on 15th November'23.
The legal basis for these changes is laid down in the Energy Act 2023.

Unlike the brief which was given to NG-ESO, ISOP is tasked with facilitating the move to Net Zero by 2050.
It's a radically different approach which will bring together external innovators to create the products and services required to reach that objective.

ISOP will cover all the bases... from the domestic smart meter right up to the new transport technologies.

Why can't the existing Octopus ToU tariffs operate under this new regime?
... because the tariff data isn't even downloaded into our Smart Meters.
Only when Octopus collects our consumption data after midnight, does it then retrospectively apply the relevant cost per half-hour.

That means I can't use my Smart Meter to issue commands to charge my home batteries.
Not so smart eh?

Or perhaps I'm over-thinking things.

What we install in 2024 needs to be identified with the Future Energy Scenarios in our mind.

That's the basis on which ISOP and its Regional Partners (RESPs) are going to be working.

Posted by: @transparent

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Or perhaps I'm over-thinking things

No further questions m'lad 😉

Hiya , brand new to this forum as I was looking for solutions with the Growatt Shine hardware and app, i find mine goes hours between updates while its supposedly sending them every 5 minutes. I've discovered if I reboot the Shine Link Lan box it forces an update. So I've put mine on a smart plug that turns off/on every few minutes. Obviously this is not a good long term solution as it might damage the hardware, but my Installers are ignoring me when I have raise this and a few other issues with them.

Thanks for the information @graemed 
You are right to chase the installers.
Your contract is with them, and is covered under the Consumer Rights Act.

What model of Growatt hardware are talking about?
And when was it installed?

What dependence does it have on the correct operation of the Shine App?

I assume that the data is being sent to Growatt HQ in China?
Have you considered that they may have been unable to respond recently due to the Chinese New Year?
A lot of companies close down for a 2-week break.

Hi @Graemed, my Growatt Shinephone App is behaving lately, but it does periodically misbehave. I have the Shine WiFi-S dongle via the home WiFi network not via a hard-wired Lan box. When the Shinephone App plays up, the log out and log back in fix sometimes works. When issues arise they are usually time-out errors accessing Growatt's servers and not issues with the data being transmitted to their servers.

Little consolation, but Growatt has never once responded to anything I've sent to them.

@allyfish Hiya, the app and dashboard constantly log me out anyway even after 10 minutes, so that makes no difference atm, the only surefire way is this power cycle the lan box. Was looking to get another one and see if it has the same issue but the installers say their warranty will be invalid if I don't use "their" (my paid for) equipment. But they are ignoring my requests for assistance. My feeling here is the lan box itself is not the issue, but the dongle and a reboot of the lan box somehow forces the dongle to connect. I have even put an extension cable for my ethernet and power and put the lan box within 1 meter of the dongle and it also has this erratic data push rate. The lan box seems to actually send every 5 minutes. The other issue could be low memory on the lan box and a reboot flushes the cache?

@transparent I have " 10 x 450w AIKO All black panels  4.5kw with 6.5kw Growatt Agile Grid charging Battery and Growatt inverter  SPH3600", Well the Installers replied initially to me with "I have checked your data and confirmed this with the Growatt technician team, they have stated its due to a weak internet connection. Is there a bast distance between your internet box and the datalogger"  and then when i replied with "I can categorically state that is not true,  I have a 900meg full fibre Internet. And this issue occurs at all times. My other Internet  devices have no issues. Also it cannot be the signal between  the inverter and shine lan box as I put that on an extension and placed it right next to the inverter and no difference. " The have ghosted me ever since.  This was only installed 2 weeks ago and i remember the technician had an issue with the dongle and sine lan box but they were in a hurry to get off so left as soon as they say the first update on the Growatt dashboard

OK @graemed that makes sense to me.

That 2-week window coincides with the Chinese New Year.
It is common for workers in cities to return to their families, just as we might do at Christmas time.

I think this is the moment to write a followup email to your installer, giving them the opportunity to use that as the excuse for their lack of response.
But this time you could use the sort of wording which places you firmly within the scope of the Consumer Rights Act.
You don't need to mention it at this stage. A threat of legal action might have the opposite reaction to what you want!

"Can I again draw your attention to the issue I responded to you about on <date>.
I confirm that there is no 'weak internet signal' at my house.
If the Growatt Shine data is not being passed between the SPH3600 inverter and the Shine LAN box, then it is due some other fault.
This appears to be intermittent in nature; failing every few minutes.

I understand that you may have been unable to obtain further technical support from Growatt during the Chinese New Year, but that is now over.

The present installation is not fit for purpose and I require it to rectified.
Please make arrangements to return to site and fully commission the Shine monitoring system, which you have left in an inoperable state."

If you should need to take the matter further (Citizens Advice Bureau or Small Claims Court), then that email provides adequate evidence of an opportunity to resolve the issue prior to the more formal "Letter before Action".

For the benefit of yourself and @allyfish may I point out that Growatt has a UK-based office which is listed on their Contact page:

They provide support for all Growatt devices which are officially designated for the UK market, and will know of those installers who are qualified/trained to install them.

I have had previous communication with their Yuming Hao, who lives and works in UK.

Although I am running a commercial R&D project, using inverter models which are not officially imported to the UK, Yuming was quickly able to find engineers at their Chinese HQ who could provide firmware upgrades and utility/analysis software for the hardware which I had brought in directly from China.

I won't give you Yuming's direct contact details here for obvious reasons!
But there should be no excuse for a UK-based installer to be floundering around with equipment that isn't working properly.
The support they require is already here in this country.

@transparent Wow thanks for that

@graemed I'm picking up here the dialogue between yourself and @majordennisbloodnok on the main Hello & Welcome topic

Posted by: @majordennisbloodnok

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The main issue I have with Growatt is that they want everyone to do everything through their app and/or web portal, yet the user interface is somewhat buggy. If you look at the Home Assistant integration for Growatt kit, you'll see there are lots of issues raised by consumers that the integration's ability to use Growatt's API is unreliable.

... to which you responded that you're a professional 'code wrangler' (or something like that) 😉 

Before you wade into a control system for your new PV/inverter/battery technology, may I raise two issues.
These are different in their nature, but I'd rather you were aware before you throw yourself into the project:

1: I have been using the RS485 ports on Growatt inverters through which to pass commands and data.

This circumvents any need to use Growatt's Shine App and/or API, but has two drawbacks:

a: their implementation of Modbus commands is not 'industry standard', but a derivation of it which they might yet extend or alter

b: there are a number of omissions in the data you can receive back; these are mainly the more serious fault-codes which only get displayed on the inbuilt LCD.
So if your inverter suffers from one of these, then you can't know of it without physically standing in front of the unit 😥 
It's possible (but I haven't checked) that their Shine system contains the same omissions.

2: The British government is devolving the strategy, planning and operation of all energy networks to an Independent System Operator and Planner.
The Ofgem licence for National Grid ESO will cease during this year (2024).

We have a detailed discussion about this elsewhere on the forum which you can read through.

ISOP has a mandate to reach Net Zero by 2050...
and I mean to actually reach it, not just have meetings and create policy!

The energy networks must attain Net Zero whilst still being secure (ie resilient against failure).
I have spent the last 4 months looking into how this could work, during which I've been in communication with senior National Grid staff and Parliament.

I don't think ISOP can fulfill its obligation whilst grid-connected equipment (inverters and storage batteries) retain the capability for commands to be sent from/via a third-party site across the internet. That is especially the case if the command route is located outside of UK jurisdiction.

It doesn't matter whether the energy equipment is a handful of 50MW storage sites, or a million inverters and batteries in the homes of consumers. If those systems are reliant on data which is being transferred via servers overseas, then there must come a point when they will not be permitted.

As you are fluent in hexadecimal, you may be able to create a strategy which circumvents the above problems...
... in which case you could have a queue of others wanting to follow in your footsteps.