Posted by: @toodles

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@derek-m Perhaps this announcement and the consequent ‘consequences’ will be worth waiting on then? Regards, Toodles.

I believe the changes have already been implemented, and I have noticed that Agile appears less volatile recently.

By the way. There is nothing wrong with Mr. Putin that a half ounce of lead would not cure. 😋 

Just read this short item - interesting as the writer obviously is thinking along the same ‘which tariff’ lines as I am! https://community.openenergymonitor.org/t/projections-of-running-heat-pump-on-cosy-octopus-tariff-uk/24250

Regards, Toodles

@toodles I have so many variables within the house that I could spend all day consumed by monitoring and managing the process to save a few pounds here and there, for me with Solar and 17kWh of battery storage the solution that gives me what I believe to be the best option is the COSY Tariff and charging my batteries during the two times (due to my inverter and how fast I can charge batteries I get from 10% to 70% full during the night and then if I get some sun during the day the second charge will take me to 90% and to 100% if the sun is shining but I always only use grid charge to 90%. I like that setup as its easy to setup and just forget it. it helps me avoid the higher rate period from 1600 through to 1900 hrs. I know I will have large electric bills during winter period but as soon as the weather starts to turn warmer than my electric usage will come down dramatically and I will start to minimise the grid battery charge times to zero. during the summer i exported at 15p and that helped offset my standing charge costs for 4 months during the summer season as well as not having a lot of grid usage. 

@andris I’m on ‘Fixed’ which yields 15 pence per kW/h.

@boblochinver Thank you Bob, I’m coming round to the same way of thinking and have contacted OE about swapping to Cosy. Agile seems to have stayed on the higher end for a while now and perhaps as someone has suggested, this is part of a plan to equalise the tariffs a little. With 27 kW;h of ca[acity, I can charge these in the three hour slots - along with the DHW heating and the domestic load. At least with Cosy, I will know what the rate is! I’ll hope not to have to use the middle and highest rate at all. Regards, Toodles.

After many months of planning, sorting funding, disruption, and weather delays, as of yesterday we now have a SE-facing 6.64kWp PV array consisting of 16 Trina 415W panels, in two strings of 8 (albeit physically arranged as 11+5 due to our weird roof; and yes, we get a spot of shading in the later part of the generation period in this low winter sun).

These are hooked up to a 5kW GivEnergy inverter with 9.5kW battery. All working nicely so far, just awaiting another non-dreich day!

We also have a 3-month-old Vaillant AroTherm 12kW heat pump which has got us through the first half of our first winter perfectly well.

An interesting discussion on the merits of different tariffs. We've been on Cosy since mid-December and it has worked well for us, even before the battery install. I too came across and read that OEM topic, and was surprised that the modeller had predicted such low savings. Our experience so far (our house, these specific conditions, etc) has blown these estimates out of the water:

Using Cosy with a sensible heat pump schedule (boost the temp by a degree or two in the cheap periods, setback to coast over the peak period, DHW runs at 4am and 1pm) has got us savings (on our total electricity bill, not just heating) of 14% compared to Flexible Octopus in the period 12th Dec - 22nd Jan - double the saving he estimated.

In our first proper day with battery running this week (but PV panels not commissioned yet) it was a whopping 33% (much closer to his estimated saving of ~30%).

Obviously not much data to go on yet, but looking forward to seeing how that improves incrementally with PV coming online, export tariff getting set up, and more sunlight!

I will also be thinking about whether to switch to Agile (and, later in the year, considering Flux or Intelligent Flux), but at the moment Cosy is putting up a pretty good fight given our setup.

Have you considered Octopus Tracker which today is 14.83p/kWh in the Yorkshire area. That is all day.

@derek-m thanks - will include that in my next round of deliberations, certainly. Though in Northern Scotland it's a less attractive 18.8p/kWh today, and the average looks to be something around 20p from a quick eyeball of the charts here: https://energy-stats.uk/octopus-tracker-northern-scotland/

@josephiah Oh for a crystal ball! We have been on Cosy for a few months now and I note of late that Agile has dropped in price again. I’ll stick with Cosy for a while as I have severe problem with my vision just now that makes close scrutiny of daily (even half hourly) changes a bit of a trial to monitor and reset on the Tesla Powerwall app. When the ASHP can see its’ holidays approaching (DHW is handled by a Sunamp Thermino from solar and / or grid power), then it might be time to rethink my regime as I may have my sight loss sorted by then and go back to just ‘poor vision’ again. Agile has been consistently cheaper than Cosy this months but without that crystal ball…. Regards, Toodles.

@toodles I'm tempted by Agile (recent and last year's costs looking pretty favourable vs Cosy), and then thinking of using a auto-scheduler for the charging.  Several options available:

• My Energy Optimiser (MyEO) - web-based, £5/month, nice-looking dashboard, takes in your historic usage, Agile pricing, and weather forecasts and chooses the best slots to charge in.  Seen a few reports of good results from users on the GivEnergy forum.
• Wonder Watt - a similar web-based tool, currently free, feels a lot more 'beta' (because it is) and homegrown, but likewise hearing a few reports of decent results.
• Home Assistant + Predbat - hugely flexible, very clever, but very complicated to set up and then maintain, requires always-on hardware (e.g. Raspberry Pi) - could potentially even schedule the ASHP as well as the battery if desired.  People getting great results once they've set it up correctly.  Much as I love a nice bit of tinkering, I think this is probably a step too far for even a mid-level geek like me - it'd be fun for a while, then urgently annoying when some homegrown library buried in it broke!

Hi,

Just joined today, had my Solar and Battery system installed March last year, here are the details:

10x LONGI 410w Panels

Growatt 3.6kW Hybrid Inverter

Growatt 6.5kWh Battery

Our roof is SSE facing, so we don't benefit from the evening sun so well, last two hours of the day are lost on average, plus there's a hill on the East side, so we lose a little potential in the morning too.  However, over the past year we've generated approximately 4,100kWh, which isn't too shabby.  Thanks to the battery, and adjustments to how/when we use power, we've managed to use a good chunk of that ourselves.

On the day the Solar was installed, March 8th 2023, there was heavy snowfall here, yet the system was already making a little power.

I suspect that the Growatt App (I actually connect directly to the server, via PC) and monitoring hardware isn't the most accurate or reliable.  I've had days where the panels are reportedly generating as much as 4.37kW peek - I have screen shots of this, it was a very sunny day - also, there have been frequent times where historical data is lost - missing days of data - though it's generally been more consistent this year.  That is, until today coincidentally, where the System is showing as Offline, since but it really isn't.  Hopefully it'll recover as I'm pretty sure it's a server-side thing.

Note: I say "Server" as that's what Growatt call the website you connect to for monitoring.  There's also a phone app, but I prefer connecting directly to the server, as that's where the App gets its data from apparently, after it's been uploaded over Wifi to the Internet of course.

Since getting Solar, we've adapted our energy use patterns to fit in with when the sun is shining.  We sorta live in out in the sticks a bit, there's no Gas here so we're 100% electric for power.  We do however have an Open fire for the colder months.  House is fairly well insulated so, this past Winter, the regular electric radiators (they're just wall-mounted convector heaters really) were never needed.

Last year, I had an Air Con unit fitted to my Office - I spent most of my time there - which as well as cooling provides heating, and is more efficient and instant that the convector heaters.  I found that this, the open fire and my heated mattress cover met all my warmth needs between them.  Being a fairly hardy soul when it comes to comfort zone temperatures helps too lol.  Soon, I hope to be getting a second Air Con unit for my Bedroom - I was 50/50 initially, but after living with the original unit through summer and Winter, I can see its value.  As it's a heat pump, it draws around 25% of the power on average for the same level of comfort.

Note 2: we did consider a Heat Pump for all heating and hot water needs, however, as the house does not currently have a regular boiler (no Gas here) nor radiators, it'd be a massive job.  Many here use Oil for heating, but that'd be a huge job too.  If I ever did want to fit traditional radiators throughout, I'd consider a heat pump but, to be honest, we're just fine with what we have.  Plus it's CHEAP as we rarely use the radiators.  When we do, not since early last year, they're great set low just to keep the edge off.  Have looked at getting a modern wood/multi-fuel burner to replace the fireplace - I know it'd be more fuel efficient - however, it'd be lot of work.  Current fireplace has a back-boiler, which gives hot water and supplies a single regular radiator in the bathroom.  So, we'd want a wood burner to do the same.

I've not tweaked anything from the defaults the Solar system came with.  While I am traditionally a tinkerer with anything tech-related, I've not really looked into things.  Plus, as it appears to be working well - from a power-generation perspective at least - I'm happy to leave it well alone.  Battery charges when there's sun shine, depletes when there's not and reverts to the grid when it's empty.  High-power devices like the electric shower (9kWh!) of course will always use some grid electric as the inverter tops out at (officially) 3.6kWh, though it's been suggested that it can do a little more than this, with 3.6 being a conservative "max".  Don't know if there's any truth to that...

Anyway, hello again, I expect I'll be asking lots of questions during my time here.

Welcome, @scoob, and thanks for posting.

What you've described is a slightly smaller setup than we've got but otherwise my experiences will translate pretty closely to your installation since we too have a Growatt hybrid inverter (in our case the SPH5000).

Posted by: @scoob

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Our roof is SSE facing, so we don't benefit from the evening sun so well, last two hours of the day are lost on average, plus there's a hill on the East side, so we lose a little potential in the morning too.  However, over the past year we've generated approximately 4,100kWh, which isn't too shabby.  Thanks to the battery, and adjustments to how/when we use power, we've managed to use a good chunk of that ourselves.

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Not shabby at all. Have you also set yourselves up with an export tariff? If so, with which provider?

Posted by: @scoob

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I suspect that the Growatt App (I actually connect directly to the server, via PC) and monitoring hardware isn't the most accurate or reliable.  I've had days where the panels are reportedly generating as much as 4.37kW peek - I have screen shots of this, it was a very sunny day - also, there have been frequent times where historical data is lost - missing days of data - though it's generally been more consistent this year.  That is, until today coincidentally, where the System is showing as Offline, since but it really isn't.  Hopefully it'll recover as I'm pretty sure it's a server-side thing.

Note: I say "Server" as that's what Growatt call the website you connect to for monitoring.  There's also a phone app, but I prefer connecting directly to the server, as that's where the App gets its data from apparently, after it's been uploaded over Wifi to the Internet of course.

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This will be very familiar with anyone with Growatt hardware but just for the benefit of other readers I'll clarify that Growatt has an API that the wifi module on the inverter talks to so it can send data every 5 minutes. They then provide a web site ( https://server.growatt.com) as a front end you can access via a browser and a smart phone app (ShinePhone) for the same functionality on your phone, tablet or other mobile device.

The Growatt hardware is, as far as my experience has been, pretty workmanlike and solid. The functionality of the web portal and phone app have proven to be rather buggy in places (I can't, for instance, set the time on the inverter) but that doesn't affect the inverter's ability to do what it does pretty well. My inverter also periodically appears as "offline" and yet it's still doing it's thing happily serving up leccy to my home, the battery and the grid in that order. Although I'm not absolutely certain, I suspect it's probably more accurate to describe the "data logger" (i.e. the wifi module - ShineWifi or ShineLAN) as "offline" than the inverter itself.

Posted by: @scoob

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Since getting Solar, we've adapted our energy use patterns to fit in with when the sun is shining.  We sorta live in out in the sticks a bit, there's no Gas here so we're 100% electric for power. 

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I've not tweaked anything from the defaults the Solar system came with.  While I am traditionally a tinkerer with anything tech-related, I've not really looked into things.  Plus, as it appears to be working well - from a power-generation perspective at least - I'm happy to leave it well alone.  Battery charges when there's sun shine, depletes when there's not and reverts to the grid when it's empty.  High-power devices like the electric shower (9kWh!) of course will always use some grid electric as the inverter tops out at (officially) 3.6kWh, though it's been suggested that it can do a little more than this, with 3.6 being a conservative "max".  Don't know if there's any truth to that...

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To be frank, "if it ain't broke, don't fix it" is not a bad mantra. The configuration your system has been installed with are certainly sounding to be fit for purpose, so why deviate too far. I will also say that it will be difficult to do any tweaking at all unless you do one of two things; fiddle with the buttons on your inverter itself or connect up to the inverter with a wired connection (either the serial port if available or the RS485 port) and use something like Modbus to talk directly with the kit.

On the flip side, if you do decide to do some tweaking the only obvious candidate I can see is to integrate your inverter with something that can make some smart decisions based on weather forecast, energy saving sessions and/or plunge prices. We, for instance, tell the battery to charge from the grid if the import price for that half hour is a negative price (i.e. we're being paid to charge the battery). It doesn't happen that often but why not take advantage when it does?

Eventually, though, it's a very personal judgement as to whether all the hassle of doing the integrating is worth the benefit you get from it. For us it was, for you I've no idea.

Happy cogitating and welcome to the fold.