There are a number of similarities in our systems; I have 8.1 kwp. of solar panels, 27 kWh of Powerwall 2 battery, similar consumption figures but no EV here.

I have been on OE’s Cosy until 1st April when I swapped to try Intelligent Octopus Flux and this I have not really had time to evaluate yet.

With Cosy, you would be able to charge your 27 kWh of PW3 in approximately 3 hours (the system can be (as mine is), set to handle 10 kW import / export as I have a G99 approval from the DNO for this. Cosy provides 3 x 3 hour slots at the cheapest rate and I found I never needed to use the middle or high rate at any time; the battery supplied everything outside of those cheapest hours.

Not having an EV, I am not able to evaluate if there are gains to be made using an EV tariff but certainly, with the Cosy slots spread over the full day, I have had no problems maintaining a charge sufficient for my needs including an 8 kW Daikin ASHP.

If you would like any more details, please let me know via this august channel! Regards, Toodles. 

We are also in NE Scotland, we have a smart meter - but does not communicate as signal is sh!te.

We are on just E7. I use home assistant to do two things

At a PV generation Watts (600W) and battery state of charge (over 97%) I start the heat pump at an elevated flow temperature and let it run the battery down to 95%.

I do similar with a big relay for the immersion in the cylinder. That doesn't start until 98% and again I run battery down to 95%. Did have a normal diverter, but with batteries not the best, so did my own thing instead.

Ideal for me, is don't export, so let battery float at just below fully charged.

I have tried smart charging strategies, but not really had a good experience, PV output just doesn't keep consistent with forecast, so either under or overcharge. At the moment I either just charge overnight to 100% if the forecast is over 30kWh I will sometimes reduce the charge down to 50%. But I run the heat pump either in heating mode or cooling mode nothing else.

If I had a working smart meter, I would just go to octopus cosy and get three bites at battery charging a day. Zero thought battery management, leave the heat pump ticking over 24/7 no chance of running on an elevated tariff.

Oops! Sorry, Cosy has a 2 hour and 2 x 3 hour slots. I tended to use the 22:00 - 24:00 to top up the battery and charge the Sunamp Thermino DHW system.

I have the Myenergi Eddi set to handle the DHW charging by Solar and / or grid. The early morning Cosy 04:00 - 07:00 slot then topped up the Powerwall again and if I need it, again the 13:00 - 16:00 slot topped things up again.

This scheme has worked very well for me and I may well go back to Cosy later in the year when ASHP needs to be woken up again. Regards, Toodles.

Posted by: @algienon

↑

After writing it all down, it looks like I need a tariff that allows as much overnight charging as possible, but that doesn't tie me into specific equipment, like an EV charger or heat pump manufacturer. Octopus used to be the go-to supplier for innovative tariffs, but it looks like others are catching up quickly. What are people's thoughts?

That sounds like eon next drive, essentially economy 7.   7hrs at 7p in return for about a 10% uplift on daytime rate.  Fixed for a year. 

I'm on it, the simplicity is attractive but of course it may change.  I charge my EV on a granny charger and run as many high use domestic appliances at night as possible.  They will pay you 15p for export if you need it.

Posted by: @toodles

↑

Myenergi Eddi set to handle the DHW charging by Solar and / or grid

Do you find that effective with a battery? I found using the small amount of watts as overspill once the battery was charged, wasn't effective at charging the cylinder via the immersion. Seemed to used way more kWh to get cylinder to 70 degs. With relay doing the full 3kW in chunks my water seems to be at 70 deg most days the sun is out.

@johnmo I have tended to regard the solar element of the charging as a bonus; not being able to predict or rely on sufficient solar at times when I require it, I mainly use Cosy cheap rate times to do the grunt work for me. We use ~2.5 - 3.5 kWh per day depending on time of year (sometimes a little higher). With Cosy being ~13 pence per kWh at such times and being able to export @ 15 pence per kWh, there is little to be gained / lost either way. (I suppose there is ~ 5% loss in conversion on the way from the Eddi - unless this process is carried out as an AC - AC process, but I suspect not. Regards, Toodles.

Thanks for the responses so far, folks. Looks like EOn Next Drive might be a contender. Two issues - no EV at the moment (but I will have a charger) and no Smart Meter. Is it time to bite the bullet and get a Smart Meter? 

Posted by: @algienon

↑

Is it time to bite the bullet and get a Smart Meter

It's always time for a smart meter, if you want access to a tariff, other than standard. E7 will require a smart meter.

@algienon our episode on smart meters drops this Wednesday…

Posted by: @johnmo

↑

It's always time for a smart meter, if you want access to a tariff, other than standard. E7 will require a smart meter.

I only discovered while recording our latest podcast episode that E7 was still around. For some reason I’d assumed it was canned a few years ago. Do you know what the tariff differential is on E7 versus a similar tariff from OE?

Posted by: @editor

↑

Posted by: @johnmo

↑

It's always time for a smart meter, if you want access to a tariff, other than standard. E7 will require a smart meter.

I only discovered while recording our latest podcast episode that E7 was still around. For some reason I’d assumed it was canned a few years ago. Do you know what the tariff differential is on E7 versus a similar tariff from OE?

We pay 30p 0830 - 0130, then 13p 0130 - 0830.

A smart meter has standard tariff and E7 tariff pre programmed and will work with either, without additional communication.

So everyone on E7 currently with a radio time switch will get a smart meter or just be moved to standard tariff.