Solar Panels UK - is it worth it?

[RedMod3]

Your results are good @PITA, have you also exclusively used the cheap GO rate this last week of good weather? Today I have a problem as my 5th terminal hasn’t been activated at 00:30, I suspect it will be activated at 01:30 so I’ll be over billed for an hour when using the granny charger and immersion.

 

[PITA]

Your results are good @PITA, have you also exclusively used the cheap GO rate this last week of good weather? Today I have a problem as my 5th terminal hasn’t been activated at 00:30, I suspect it will be activated at 01:30 so I’ll be over billed for an hour when using the granny charger and immersion.

Yeah, I've been mixing it around this week. How it works for me is like this...

Our Tesla Powerwalls are still on Time Based Control at the moment. So the AI uses Go Tariff during the night to top up the Powerwalls from the Grid.

If we then have a poor Solar Day, our home usage is then easily covered by the cheap Grid storage.

However, if we have an unexpected good Solar Day... the excess gets put into the cars.

All I need to do here, is plug our 7kW charger in... and from the Tesla App, select 5% or 10% extra needed and start charging. It then drains the excess power from the Powerwalls... allowing more storage space for more Solar.

So literally nothing gets exported, and we don't get caught short by having to use Peak Rate electric...

 

[RedMod3]

My AI is not working well enough as my PW didn't charge up enough last night. In an hour, I'll be on grid power, as we generated just 12kWh today.

Yesterday was odd. The PW became fully charged and then my immersion CT cut in to heat our water; I would rather the surplus power had gone into another PW, which I am due soon.

Meanwhile the Tesla App ver 1.71 will not let me view or change any of the parameters in Time Based Control; blocking of this feature started after ver 1.61. I've reported this to Tesla.

 

[PITA]

Here's an example from Saturday...

Grid use : only between 00:30 and 04:30

Powerwalls powered the house all day long.

Solar charged the Powerwalls during day.

We got home later in the evening in the car and immediately took all that Stored Solar and transferred it into the car, straight from the Powerwalls

 

[PITA]

My AI is not working well enough as my PW didn't charge up enough last night. In an hour, I'll be on grid power, as we generated just 12kWh today.

Yesterday was odd. The PW became fully charged and then my immersion CT cut in to heat our water; I would rather the surplus power had gone into another PW, which I am due soon.

Meanwhile the Tesla App ver 1.71 will not let me view or change any of the parameters in Time Based Control; blocking of this feature started after ver 1.61. I've reported this to Tesla.

I was expecting a poor Solar Day today... but got over 20 kWh... which can catch you out if you can't 'dump' it somewhere useful.

Weather forecast clouds.. but we had Sunshine...

 

[RedMod3]

You are fortunate, I need my 2nd PW asap. Tell me, do you see options for Time Based Control as I don’t.

 

[PITA]

You are fortunate, I need my 2nd PW asap. Tell me, do you see options for Time Based Control as I don’t.

Nope... in Time Based Control, the Tesla AI takes over... just leave it in this setting and let 'it' decide how much to download overnight.

The only other section (if you scroll down the App Screen) is to enter your time Based tariff costs...

Having said that, once April arrives I might put mine in Backup Mode, once we start getting 30 to 45kWh per day, we won't need any stored Grid power

 

[RedMod3]

I used to have a Utility Rate Plan option, but that has disappeared.

 

[PITA]

I used to have a Utility Rate Plan option, but that has disappeared.

If I remember right, these options in the app will appear after a few days...

 

[sparkymark75]

Are there any Solis inverter users amongst the solar/battery users here?

The reason I ask is that I am having a recurring problem with mine and wonder if my experience is typical.

The system was installed in Jan by EEC (based in Southport) and includes 8 panels producing just under 3 kWp and 8.2 kWh Pylon battery. It runs fine so far as I can tell, and has reduced reliance on high cost grid electricity to zero on some days, given the battery charging overnight and topped up via solar. The problem is with the datalogger.

From around mid-Feb the data reported by the datalogger has become patchy (on/off, on/off) with hours reporting nothing then back to life again. There is a good wifi signal all the while, and even during the outages the datalogger is still broadcasting its IP address and can be logged onto. The inverter is still operating as it should and the data is still visible on the screen on the inverter itself throughout, just not broadcasting to the app/website. The inverter is in the garage so a bit of a pain to go outside and check).

I reported this to the installer who have been useless (I have had other problems with them before, so approached them again on this with a heavy heart), deflecting, deferring, fobbing me off, insisting I need to speak to the manufacturer. In an effort to get the matter resolved I did speak to the manufacturer who to be fair to them did engage and have provided a replacement datalogger. The new datalogger worked fine for the first couple of hours, then stopped again. Same routine - IP address is visible, datalogger is 'reachable' but doesn't want to broadcast data consistently, if at all.

Image below is typical and is from last night showing the point the new datalogger fell over for the second time.

View attachment 786572

I have a Solis inverter with a datalogger I setup myself (installer was too expensive!). I’ve had one issue since it was setup at the end of last year. I think I fixed that by resetting the datalogger.

I also find that sometimes the datalogger is working but the Solis cloud website reports nothing. When that happens, I check it using another Solis app (Solis Home) which seems more reliable but is older. It pretty much always reports the data.

 

[HenryT]

Thanks @sparkymark75 that's encouraging.

I've done the reset on the datalogger too (remove the aluminium case and hold down the little button) but still get the drop outs on the new datalogger as well.

When mine goes off neither the website or the app report any data, but the datalogger still broadcasts its SSID and is reachable so remains 'alive'. I can re-run the wizard to confirm settings, but still no data at that point. It seems most likely that in my case, that it's actually the inverter falling asleep, so far as data reporting is concerned, as if I scroll through a few pages on the inverter display the data feed resumes again a while later. Frustrating and a bit of a pain but I guess I can live with it.

More encouragingly, have had a few 'perfect' days recently when grid use has been limited to overnight cheap rate car and battery charging. House has run entirely from battery/solar.

 

[RedMod3]

If I remember right, these options in the app will appear after a few days...

hmmm....meanwhile the AI is hopeless; it charged the PW to 60% and I've been on Grid power since 11am. It is a shame we can't set a target PW charge %.

 

[ACarneiro]

hmmm....meanwhile the AI is hopeless; it charged the PW to 60% and I've been on Grid power since 11am. It is a shame we can't set a target PW charge %.

Yes, the AI seems to assume that yesterday's conditions will be the same today. There doesn't seem to be much forecasting going on.
Shame, Tesla could buy that info from the likes of Solcast to make better battery management decisions....

 

[squarepeg77]

Oof, just got quoted around £12k for single Powerwall and around £6300 for Givenergy 8.2kWh system here in Hertfordshire. Quite the markup on the wholesale prices I’ve seen… and it’s only probably half a day’s work for an electrician (IMO). Fairly straightforward garage installation - seems to me should be about the same difficulty as a car charger installation.

 

[phil4]

yeah, that's a bit on the high side... Tesla want £9300 ish inc VAT and hardware... so yes, making a margin on the install bit.

That's I think the dumb thing... as you can see the price on Tesla's site. So it's blatantly obvious.

 

[PITA]

Oof, just got quoted around £12k for single Powerwall and around £6300 for Givenergy 8.2kWh system here in Hertfordshire. Quite the markup on the wholesale prices I’ve seen… and it’s only probably half a day’s work for an electrician (IMO). Fairly straightforward garage installation - seems to me should be about the same difficulty as a car charger installation.

Ouch... I paid £8,600 for my original Powerwall 2 and Gateway 2 including installation about 18 months ago during the Pandemic

But then £10,000 for my 7.2kWh Solar Array with 5kW inverter.

So overall about the same...

 

[94jdh]

Ouch... I paid £8,600 for my original Powerwall 2 and Gateway 2 including installation about 18 months ago during the Pandemic

But then £10,000 for my 7.2kWh Solar Array with 5kW inverter.

So overall about the same...

Is squarepeg77 talking about £6300 for the Givenergy battery installed or for a battery and solar array?

 

[squarepeg77]

£6300 for Givenergy 8.2 kWh battery and 3kW AC inverter. (I already have PV, so this is a “retrofit”)

 

[PITA]

£6300 for Givenergy 8.2 kWh battery and 3kW AC inverter. (I already have PV, so this is a “retrofit”)

Sorry, my mistake... I misread your comment

 

[94jdh]

For those wondering about 0% VAT on battery install only this was the reply on HMRC forums:

the installation of batteries on their own were not covered under the 5% rate, they were only charged at the reduced rate if supplied together with a solar panel as a single supply.
So the new 0% rate will not apply to solar batteries installation on their owm.

No credit to me, someone else posted.