Solar Panels?

Author
Discussion

silentbrown

8,793 posts

115 months

Wednesday 29th March 2023
quotequote all
jesusbuiltmycar said:
Quick question - do any of you have an old style mechanical meter with a spinning disc? my Wife's friend has 20 panes and hers "goes backwards" when the Solar panels generate more electricity that she uses.

Is that an issue with suppliers?
If the whole meter goes backwards, she's effectively receiving 35p for every surplus kWH delivered to the grid!

https://greengumption.co.uk/2015/11/electricity-me...



markiii

3,564 posts

193 months

Wednesday 29th March 2023
quotequote all
supposedly you should tell them, but its effectively a free battery

Arnold Cunningham

3,758 posts

252 months

Wednesday 29th March 2023
quotequote all
Rubbish weather today and I may actually have to use grid power during peak time - battery is down at 32% at the moment.

Total generation today is 3.22kWh compared to 20kWh 2 days ago. I know during darker months I'll have to increase the amount I pull in to the battery overnight, but was hoping to avoid that from about now onwards.

pingu393

7,716 posts

204 months

Wednesday 29th March 2023
quotequote all
Arnold Cunningham said:
Rubbish weather today and I may actually have to use grid power during peak time - battery is down at 32% at the moment.

Total generation today is 3.22kWh compared to 20kWh 2 days ago. I know during darker months I'll have to increase the amount I pull in to the battery overnight, but was hoping to avoid that from about now onwards.
We're on 22%. It's one of those days.

I was cheered up to learn that I made £8.82 on the latest Octopus Saving Session

silentbrown

8,793 posts

115 months

Wednesday 29th March 2023
quotequote all
markiii said:
supposedly you should tell them, but its effectively a free battery
Better than that, it's a 100% efficient free battery of unlimited size, that doesn't degrade over time.


markiii

3,564 posts

193 months

Wednesday 29th March 2023
quotequote all
indeed, tbh I think everyone should have that ability, saves the energy companies a fortune during generation times in terms of what they need to supply

Road2Ruin

5,167 posts

215 months

Wednesday 29th March 2023
quotequote all
pingu393 said:
Arnold Cunningham said:
Rubbish weather today and I may actually have to use grid power during peak time - battery is down at 32% at the moment.

Total generation today is 3.22kWh compared to 20kWh 2 days ago. I know during darker months I'll have to increase the amount I pull in to the battery overnight, but was hoping to avoid that from about now onwards.
We're on 22%. It's one of those days.

I was cheered up to learn that I made £8.82 on the latest Octopus Saving Session
On 72% myself of a 9.5kwh battery. Not cooked dinner yet though. Should still see me through the evening.

Arnold Cunningham

3,758 posts

252 months

Wednesday 29th March 2023
quotequote all
Road2Ruin said:
On 72% myself of a 9.5kwh battery. Not cooked dinner yet though. Should still see me through the evening.
I have a pair - so 19kWH. But I currently only charge the battery up to 60% during off peak to give me enough headroom the next day if it's a bit sunnier.
So took the battery up to 60% by 4:30am this morning, but having only produced 3.5kWh today, the batteries are now down to 23%.

Really, it'd be nice to say "weather looks rubbish tomorrow, max out the battery charge during the off peak period". I am sure I could write something myself to do this, but work is a bit busy at the mo. Anyway, it's no sweat, remain very happy with the system and the huge drop in both grid energy consumed and what fairly grid energy we've consumed since install is almost entirely (except maybe not this evening) from off peak tariffs.

I was already thinking that a winter charge setting for the batteries may be up to 100%, not 60% - but I dunno until we get there.




Edited by Arnold Cunningham on Wednesday 29th March 18:11

markiii

3,564 posts

193 months

Wednesday 29th March 2023
quotequote all
can you manually overide on a nightly basis?

Arnold Cunningham

3,758 posts

252 months

Wednesday 29th March 2023
quotequote all
Oh for sure, but I'd rather it be hands free for as much of the time as possible.

I think my current schedule is good enough for an average day at this time of year - but not quite good enough for a rubbish day. But if I tweak it for a rubbish day, this means I'll consume more from the grid on an average day, unnecessarily, and end up dumping more solar power back in to the grid on average days.

On Average or Good March days, we have enough solar capacity that the battery doesn't fall below the night time charge threshold I have set - which is great. Even more battery capacity would smooth the peaks and troughs even better - but I think 19kWh is plenty given how expensive batteries are.

Enut

750 posts

72 months

Wednesday 29th March 2023
quotequote all
jesusbuiltmycar said:
Quick question - do any of you have an old style mechanical meter with a spinning disc? my Wife's friend has 20 panes and hers "goes backwards" when the Solar panels generate more electricity that she uses.

Is that an issue with suppliers?
I have a friend who also has an old style meter, pretty sure he is being very careful to make sure he always uses a little between readings as the supplier may well insist he goes onto a smart meter (which he doesn't want) or suspect that he is tampering with the meter if the reading goes down.

Chris Type R

8,018 posts

248 months

Wednesday 29th March 2023
quotequote all
Enut said:
jesusbuiltmycar said:
Quick question - do any of you have an old style mechanical meter with a spinning disc? my Wife's friend has 20 panes and hers "goes backwards" when the Solar panels generate more electricity that she uses.

Is that an issue with suppliers?
I have a friend who also has an old style meter, pretty sure he is being very careful to make sure he always uses a little between readings as the supplier may well insist he goes onto a smart meter (which he doesn't want) or suspect that he is tampering with the meter if the reading goes down.
They might insist he has a new meter at some point, without smart capability enabled.

My in-laws agreed to a smart meter a few years ago, which they regretted once they started receiving 'normal' electricity bills. I think most of their production is returned to grid on a not massively beneficial FIT agreement.




gareth h

3,503 posts

229 months

Thursday 30th March 2023
quotequote all
Is any body able to give me some budget costs, I’m trying to work out whether I am better investing in PV and battery or just a battery and charge it off peak.
Our daily consumption is circa 10-14kwh, so I guess a 10kw battery and we can shift some of our consumption to the off peak hours (dishwasher, washing machine etc)
Our extension will have a 6m x 2.5m south facing pitched roof with no shading.
Thanks
G

Arnold Cunningham

3,758 posts

252 months

Thursday 30th March 2023
quotequote all


This is the screenshot of my octopus dashboard from a couple of days ago I posted on the previous page.
For me, the combo of battery+solar means I can store enough power to go over 24 hours with 0 solar production at all. Plus the battery means I can do scheduled charging. So you can see the substantial reduction in energy consumed from the grid by using the battery to make the best of the solar production, plus anything I do consume from the grid is now at an off peak rate. It is a win/win in that regard, albeit, the upfront cost is still pretty high.

dmsims

6,450 posts

266 months

Thursday 30th March 2023
quotequote all
What's the ROI for the battery?

Arnold Cunningham said:


This is the screenshot of my octopus dashboard from a couple of days ago I posted on the previous page.
For me, the combo of battery+solar means I can store enough power to go over 24 hours with 0 solar production at all. Plus the battery means I can do scheduled charging. So you can see the substantial reduction in energy consumed from the grid by using the battery to make the best of the solar production, plus anything I do consume from the grid is now at an off peak rate. It is a win/win in that regard, albeit, the upfront cost is still pretty high.

Condi

17,088 posts

170 months

Thursday 30th March 2023
quotequote all
Is anyone with solar + battery on the Octopus Flux tariff?

https://octopus.energy/smart/flux/

Arnold Cunningham

3,758 posts

252 months

Thursday 30th March 2023
quotequote all
dmsims said:
What's the ROI for the battery?
Yeah, that's the 16K question - which is what my total setup was.

"As is", I think I worked out it'd be 4.7 years - but I don't have enough data to be precise on that at all, yet.
ie, Taking march as an average month, I'm already seeing close to a 90% reduction in my energy bill.
If this pattern is reliable enough, I expect we'll probably be able to consume close to 0 off the grid during the summer months.

And during the winter months when solar production will be rubbish, we'll still be able to fall back to off peak grid consumption only, I think - which will still be a 75% saving on the Go tariff.

But then on top of that, we're unlikely to consume on a like for like basis. Since I do not have a FIT, I will instead heat the kids pool (intex above ground thing), which runs at 3.13kW.
So if I have spare capacity from the panels, I'll dump that in to the kids pool heater, which could work out at 36kWH per day on top of normal use (3.13kW electrical power rating, 50% duty cycle)

36x0.42=£15 per day - across the 3 months of "summer" - which works out at about £1360 extra, but is also not a like for like comparison.
But then will electricty prices drop dramatically? Or go up even more? Who the hell knows.

So what is the comparison? I dunno. In all cases I'll try to manage to keep grid consumption as low as I reasonably can.

Edited by Arnold Cunningham on Thursday 30th March 12:08

gfreeman

1,729 posts

249 months

Thursday 30th March 2023
quotequote all
Enut said:
jesusbuiltmycar said:
Quick question - do any of you have an old style mechanical meter with a spinning disc? my Wife's friend has 20 panes and hers "goes backwards" when the Solar panels generate more electricity that she uses.

Is that an issue with suppliers?
I have a friend who also has an old style meter, pretty sure he is being very careful to make sure he always uses a little between readings as the supplier may well insist he goes onto a smart meter (which he doesn't want) or suspect that he is tampering with the meter if the reading goes down.
I have heard tales of suppliers finding out and back charging an estimated benefit, to which there is very little you can do about it.

pingu393

7,716 posts

204 months

Thursday 30th March 2023
quotequote all
Arnold Cunningham said:
dmsims said:
What's the ROI for the battery?
Yeah, that's the 16K question - which is what my total setup was.

"As is", I think I worked out it'd be 4.7 years - but I don't have enough data to be precise on that at all, yet.
ie, Taking march as an average month, I'm already seeing close to a 90% reduction in my energy bill.
If this pattern is reliable enough, I expect we'll probably be able to consume close to 0 off the grid during the summer months.

And during the winter months when solar production will be rubbish, we'll still be able to fall back to off peak grid consumption only, I think - which will still be a 75% saving on the Go tariff.

But then on top of that, we're unlikely to consume on a like for like basis. Since I do not have a FIT, I will instead heat the kids pool (intex above ground thing), which runs at 3.13kW.
So if I have spare capacity from the panels, I'll dump that in to the kids pool heater, which could work out at 36kWH per day on top of normal use (3.13kW electrical power rating, 50% duty cycle)

36x0.42=£15 per day - across the 3 months of "summer" - which works out at about £1360 extra, but is also not a like for like comparison.
But then will electricty prices drop dramatically? Or go up even more? Who the hell knows.

So what is the comparison? I dunno. In all cases I'll try to manage to keep grid consumption as low as I reasonably can.

Edited by Arnold Cunningham on Thursday 30th March 12:08
42ppkWh is very expensive. Flexible rate is 32.81ppkWh

What is your estimated annual usage in kWh? Multiply that by £0.3281. That is your maximum annual saving. You can't save the standing charge.

Adding "realism" to models is always the hard bit...

You can then add an estimate of exported kWh. Multiply that by your export rate. That can also go into the ROI calculation.

You can try to estimate spliting your usage between cheap and expensive tariffs.

You can use a different rate that you could be on (for instance Octopus Tracker). That's a daily tariff, so you would need to estimate the rate.


M1AGM

2,290 posts

31 months

Thursday 30th March 2023
quotequote all
Arnold Cunningham said:
I have a pair - so 19kWH. But I currently only charge the battery up to 60% during off peak to give me enough headroom the next day if it's a bit sunnier.
So took the battery up to 60% by 4:30am this morning, but having only produced 3.5kWh today, the batteries are now down to 23%.

Really, it'd be nice to say "weather looks rubbish tomorrow, max out the battery charge during the off peak period". I am sure I could write something myself to do this, but work is a bit busy at the mo. Anyway, it's no sweat, remain very happy with the system and the huge drop in both grid energy consumed and what fairly grid energy we've consumed since install is almost entirely (except maybe not this evening) from off peak tariffs.

I was already thinking that a winter charge setting for the batteries may be up to 100%, not 60% - but I dunno until we get there.




Edited by Arnold Cunningham on Wednesday 29th March 18:11
I charge my batteries to full every night on the off peak. If I overproduce solar and export to the grid the difference is 3.5p. I’ve got better things to be doing than worrying about a few pennies and risking paying 34p because it turned cloudy when I was hoping for sunshine.