ACarneiro
Active Member
The little red light on the meter doesn’t even flash, it’s just onand if you're feeling cold jsut warm your hands on the CU
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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
ACarneiro
Active Member
Yes, I think it takes some time above the rated current for the fuse to blow.In the past I've pulled 20.5 kW on my 80 Amp fuse - had to rack that back to a max 18.4kW!
PITA
Model 3 Performance
Most I've seen is 26.5 kW for a few hours... and I'm getting another 11kW car charging on it soon.
Will be interesting to see if it'll get up to 35 kW for next Winter...
Pete UK
Member
Quote 3;Hi all,
Hope you’re all doing good. I recognise some of you from the Model Y Delivery thread. Long post coming up….
Spent the last week reading this whole thread !
Thanks to all who have been kind enough to share some very very helpful info.
I’ve had the Model Y for a complete year now. So I’ve got good usage data on that. (14,000 (normal type of remote defrosting and sentry/ dog mode) miles a year = 4,500kW. Hope that’s useful to someone.
We are getting a solar PV and battery system sorted. Possibly looking at an air-rad heat pump in a year or two (at the mo using gas rads and electric water cylinder which seems to be on all the time and pumping hot water around a loop in the house). Had 2 quotes in so far but I didn’t really like the system set ups and the installers didn’t seem all that knowledgeable about battery storage, how to design a system to best make use of energy plan time of use or had much flexibly with panels or batteries or power-cut back up etc. it was just a case of “ok we’ll add some more and this is the battery. oh ok, we’ll add one more then, oh ok add 2 more then!) Roof plan and panel numbers was easy; Just put as many as possible up there, despite the orientation !
I am a relatively high user (that doesn’t sound at all that good reading it back)
Was thinking of going down the powerwall and TEP route until they closed it last week)To me that would have worked and saved about an extra £1,000 a year just by having access to the plan plus the Solar savings of £2,500 a year on 7,000kW generated instead of buying at current SSE rate of 0.35p.
South side of the roof is 3 stories up (The front, not much space). North side (obviously perfect for panels but facing the wrong way!) east side not ideal due to stepping down half way and some shading at certain times of the year. No West roof. It’s a Victorian semi.
Quote 1;
9.96kW panel system. (Estimated generating 7,000kW pa)
24x 415W panels; 5 south, 8 north, 11 east.
6kw Solis hybrid inverter with pure storage 2 5kW DC battery attached to it- N&S strings.
3kW inverter (not connected to battery!) - E 2 strings.
Optimisers on 9 of the panels !
Total cost: £16,100 (incl 5% discount)
£12,500 equipment, £3,500 electrical and roof work, scaffolding £1,000
Quote 2;
11.45kW system (Estimated generating 7,000kW pa)
27x 425 Panels; 5 South, 8 North, 14 East
10kW (2x5) Power mate P5 inverters
27 Tigo optimisers
15.3 kW batteries (3x power mate P5.1)
Total cost: £21,300
Quote 3; TBA
The installer that I am waiting for the quote on, I think is the best qualified and knowledgeable. Also very busy. But also has a very good reputation. They use all the Solar edge inverters and SE DC batteries as well as being an authorised Tesla Powerwall installer. I haven’t got the quote back from them yet as they are still designing the system. The design I think will be very optimal. For example 1) it’s DC so unlike the powerwall it doesn’t go DC—>AC—>DC—>AC again. Just DC—>AC. Losing maybe 3% instead of 9%. So that’s a 6% gain just there! 2) You can send the peak “clipped” load direct to the battery instead of it going through the inverter! So you’d capture that valuable % extra as well. The proposed 10kW Solar Edge battery you can schedule it to charge off peak (or not, or some) using different profiles (as many as you want) one for each quarter, month, week or day if you want !). That gives it a set and forget advantage that you can’t do with the Powerwall. To maximise off-peak usage without faffing about every day with forecasts. I like that idea.
But then I like to Powerwall as well, as it fits with the car and charger and has ONE clean interface. But if I’m having to faff with 3 other interfaces all the time then that’s not as good.
Useage; 19,000 total pa (probably 30 kW a day in summer? 50 in winter? Excluding the car)
House 14,500 (planning IO)
Car 4,500
(Solar -7,000 hopefully)
I’m pretty sure our largest usage is;
1) 7.4kW rated electric underfloor heating mats in a 30+ Sq m kitchen with no other heating source. (Planning to add 2 radiators instead). Plus 4 other small underfloor mats in bathrooms and a garage sized garden studio.
2) The hot water cylinder water that’s pumped around in a loop and heated almost 24/7.
I’m thinking I need the max panel version due to non optimal roof and probably 30kW of SE storage. I don’t mind paying for it if it works, it’s reliable and I don’t have to faff about with it every night. Although I do like a bit of faffing and tweaking
I’m happy to charge the car at 10p for up to 6 hours on IO. That’s 25% to 80% car battery top up, so thats as close to the max I’d do anyway. More like 60-80% most days.
Any car charging from excess in the summer will be a bonus. Worst case £450 a year at 10p is ok. £37.50pm to run the car is a bargain!
Getting some good feedback on the Powerwall pro’s and cons here but…
My question is this;
What do you think?
Has anyone got a full Solar Edge PV inverter system with SE battery, SE smart water system? Grid- down backup? Is it any good? Is it worth the expected extra outlay? Will it play nicely with the Tesla Gen 3 wall connector/ Model Y?
Thanks again for all the hard work and tips. Guess I’m looking for confirmation on what I’m thinking already. Which is now erring towards an integrated Solar edge system when it was Tesla before. I know I can’t off set it all but want gain the most savings. If I can save £3,500 a year it seems worth the investment. That’s a good rate of return.
Cheers !
9.36 kW system (Estimated generatiing 6,900kW pa)
24x 390w Trina vertex S
24x optimisers (£100 ea)
1x SE 5000H inverter
10kW SE battery
Smart water diverter
Scaffolding, electrical and labour.
£35,350
- 10kW SE battery is coming in quoted as £9,620 - £9,800 with connection kit.
£6,000 for the panels.
£2,400 for the scaffolding
£2,400 for the inverter
£3,000 for the panel installation
£4,000 for the panel mounting kit.
Quite an eye watering quote that one !
ACarneiro
Active Member
Also, seems a bit harsh to have a 5kW inverter on a 9.3 kWp system.Quote 3;
9.36 kW system (Estimated generatiing 6,900kW pa)
24x 390w Trina vertex S
24x optimisers (£100 ea)
1x SE 5000H inverter
10kW SE battery
Smart water diverter
Scaffolding, electrical and labour.
£35,350
- 10kW SE battery is coming in quoted as £9,620 - £9,800 with connection kit.
£6,000 for the panels.
£2,400 for the scaffolding
£2,400 for the inverter
£3,000 for the panel installation
£4,000 for the panel mounting kit.
Quite an eye watering quote that one !
I’m on a 9.6 kWp with an 8kW inverter and produce around 8MWh per year
The house uses between 10 and 15 kw a day of normal use, cooking, washing machine, computers etc etc.
The battery holds 13kw, not sure what the actual usage of that is.
Charge both the car and the battery overnight on Octopus Intelligent (2330 - 0530) By 0530, both the car and the battery are fully charged.
Battery discharges throughout the day, providing the power for the house. The car is never charged outside of the off peak hours.
By the time we get to 2330, even in winter, the battery is holding anywhere from 12% up to about 40% on a really sunny day.
There have been occasions when the battery is emptied by about 1900. In this case, we draw some peak power from the grid, but usually it's after dinner has been cooked, and the kids are winding down for bed, so the load on the house is much less, approx 500watts per hour. In this scenario, we would pull a couple of kw from the grid before the off peak times kick in again.
Dishwasher is always run on a delay timer overnight, as is the heated clothes drier, as is the tumble drier if required. As mush usage as possible is time shifted using tapo plugs where necessary.
Setup for charging batteries is controlled by the Growatt app. It can be set to charge, discharge or just be ignored and run from grid power all through the app
Works for us, and means we don't have to worry about running out of power on most days
Pete UK
Member
I think this is the type of usage I am aiming for and the electricity tariff I want to be on. Makes good sense. Even if you have to draw a bit a peak at times. Although I think I need a bit more battery storage.
Pete UK
Member
It does at first, but the inverter can go over that (for a while, I believe?) and with my different roof alignments I don’t think my peak would get much above 5kW anyway. Also if it did, they extra clippings would go straight into the battery, so it wouldn’t really matter too much I don’t think. Assuming the battery wasn’t full.
Have I got that correct?
The Solar Edge system does look good but - it isn’t cheap from the supplier that quoted me. Reckon I need about 30kW storage so that would be another £20k
Pete UK
Member
I’m now going back to considering option 2;
Which was the 11.45kW panel system (27 x 425w panels) on two 5kW inverters with CYG batteries.
Anyone got any experience of CYG batteries?
They are LFP and supplier no.2 is suggesting adding in blocks of 5kW (4.6 usable) max is 4 on an inverter. So could add 6 or 8 of these I think - for 28kW or 37kW storage.
Just trying to establish their charge/ discharge rates. Think it’s 5kW but not sure if that’s per inverter or total. Presumably it’s per inverter, so that’d allow me to charge the car and batteries in the 6Hr Intelligent Octopus window nicely.
Which was the 11.45kW panel system (27 x 425w panels) on two 5kW inverters with CYG batteries.
Anyone got any experience of CYG batteries?
They are LFP and supplier no.2 is suggesting adding in blocks of 5kW (4.6 usable) max is 4 on an inverter. So could add 6 or 8 of these I think - for 28kW or 37kW storage.
Just trying to establish their charge/ discharge rates. Think it’s 5kW but not sure if that’s per inverter or total. Presumably it’s per inverter, so that’d allow me to charge the car and batteries in the 6Hr Intelligent Octopus window nicely.
The way to work out your battery needs in the winter if the aim is to be off peak , is generally about 80% of house usage needed in battery power.
In the summer, I'm hoping I won't need to top the battery up overnight, and we can be off grid with the house power (Car will still need off peak from grid) as from sunset to sunrise, the battery will have enough to get us through without the overnight top up
In the summer, I'm hoping I won't need to top the battery up overnight, and we can be off grid with the house power (Car will still need off peak from grid) as from sunset to sunrise, the battery will have enough to get us through without the overnight top up
Pete UK
Member
80% ok that’s a good figure to have in mind. Thanks.
I’m also thinking of the potential for a heat pump in the future, not sure how much that would use per day in winter either, so I’m thinking maybe aim to oversize the batteries I need now or at least have some expansion capability for later. Hence the thinking of 30kW capacity now, expanded to 40kW if needed later. It’s all a bit guess work really isn’t it? Not sure to bite the bullet now and have extra spare capacity, in case prices go up significantly or to add later.
It a tough one.
WannabeOwner
Well-Known Member
Run it overnight on Off Peak, and insulate the house so you don't need it during the day.
If we go away for the weekend in mid winter, and turn the heating off / down, it loses about 1C a day
Actually ... if you insulate it to that level you won't need a heat pump
Here's a graph showing the daily kWh used by our heat pump from 1st November - yesterday. It varies significantly based on the outside air temperature, so some days we may only use 5 or 10kWh but on the coldest day we used 52 kWh.
Our house is a 4 bedroom barn conversion (circa 150 square metres), with a 12 kWh LG Therma heat pump.
Our house is a 4 bedroom barn conversion (circa 150 square metres), with a 12 kWh LG Therma heat pump.
Attachments
If for example a good number of the panels are facing north and you care more about total outout then peak output then undersizing an inverter is reasonable.
Pete UK
Member
WannabeOwner
Well-Known Member
if you insulate it to that level you won't need a heat pump
Temperature in the area (open plan) we use to watch Telly at night
Sadly my outdoor thermometer is bust (bottom green line) so there is no line for outside temperature. The red bars are when the heating was on, yellow at the top is the room temperature, and green square-wave line the thermostat set (e.g. set-back each night)
Max/Min Temperature over same period lifted from a local weather station
take your gas usage and work out kwh gas used and if you use it for cooking too take off a couple of %. take 80% of that figure to get actual heat output (not gas usage due to inefficiency) and then divide by 3-4 for COP of a HP.
eg 100kwh gas used, 80kwh heat estimated, 20-25kwh (3-4 COP)
if you’re still only just thining about heat, I’d consider that separately and focus on house load now. Battery may not be the best solution for HP when you get to it (utilisation only part of the year, how do you size for worst case/average case etc).
