Solar panels and battery - any real world reccomendations?

So the battery usage test is complete.
I started at 3am, and it finished just before 2pm.

It recorded yield of 8.9kwh, but I miscalculated the discharge and it wasn't empty by midnight so approx 0.2kwh of yield was included before the batteries charged to 100%.

As such yield from 100% to 10% SOC (90% usage) was 8.7kwh!!!
I accept there will be some conversion losses, but thats 79% of quoted useable.
To be honest if I was achieving real world 10kwh vs 11kwh quoted I would accept that, but 8.7kwh against 11kwh quoted is not on.

Bounced back to installer, so lets see what they say this time.

Luckily the sun is now out and 4.3kw from panels. Hopefully a couple of hours and I will be on PV and stored PV until I can recharge tonight.

Will stick a screenshot up later.
 
Octopus had my export mpan Friday and yesterday it was enrolled and I submitted meter reading. Today can see yesterday's export on the app as well, they've turned that around in 9 days which is much quicker than expected.
 
200sols said:
Yes they do. For some reason reason require an opening reading. Can see yesterday's 30minute readings on the app.
Click to expand...
I done an oopsie with mine, I sent an email reply with my export number from the meter direct via photo taken on phone then when I logged into site they said they wanted a meter reading and I just assumed as it was the same day as my official end of cooling off period so assumed they wanted another standard meter reading, I submitted 74 via email picture then put in 1336 as reading before noticing it took me after submitting to a page with only 1 reading and thats when I clocked on lol

Had to give em a call and sort it out or it woulda been a few years til I caught up to 1336 from 74 on export.
 
chris1012 said:
I am early onto my PV journey and after some initial research I have got in touch with some MCS approved installers that will install in North East London.

Each of the installers have come back with a different design ranging from 12 panels to 20 panels! 18 would be ideal!

I have attached the diagram that looks to me most likely achievable however I still have reservations on the design due to the blue highlighted ridge line (around 20cm tall) which could/will cause shading? None of the installers have called out shading as of yet...

The 1st dormer flat roof is on a higher level to the 2nd rear dormer flat roof as well, please see attached photo's.
What is the maximum amount of panels I can install?
Is there any way of getting an accurate survey done?

Roof estimated sizes are -
Roof 1 - 490cm by 270cm (velux windows are 60cm by 60cm)
Roof 2 - 495cm by 320cm
Roof 3 - 285cm by 260cm
Roof 4 - 360cm by 300cm (Velux window 150cm by 130cm)

What would be a realistic price for the following? -

6000kW annual usage (12-15kW daily)

16 - 18 panels 415Wminimum, although happy to pay for more powerful panels if they still fit on the roofs.
6kw+ Inverter
10kWh+ Battery
Solar Optimisers (for shading?)

G99 - If we go for the above setup, my basic understanding is that we would need a G99 DNO application submitted?
Should we get this done prior to finding an installer in case the application was rejected?
What would happen if we had the setup installed and the G99 application was rejected?
*UK Power Networks is our provider, not national grid

Hot Water Cylinder - We have 250L indirect cylinder in the house that is setup to run in the early hours on the morning for 2hrs each day to heat up the water (predominantly using the boiler/Gas to heat up).
Should we put the cylinder on fully electric? I understand it would take a much longer time to heat up.

Are there any other considerations to make and any recommendations on reputable installers for London?
There seems to be plenty of MCS installers around at the moment so would be good to know what to look out for, as I have heard and read a number of horror install stories!

If the costs were too high, for the ideal setup, would it be advisable to install the panels and inverter now with wiring setup for future purchase of a battery?


Click to expand...

Consider rotating panels to landscape on the top 2 roofs to get more on.
UKPN are pretty good, contact their G99 team and ask for a quote to connect, they've been known to come back quickly and that may determine the maximum worthwhile size of the system.
Your shading concens from the roof to the west?
Hot water I woudn't touch as you can export electrcity for meaningful more than the cost of gas right now, unless your motivation is to be green/self-sufficient over ££. See previous comments on this in this thread. FWIW indirect is ideal to heat with solar via the immersion which is presumably already fitted.
System of this type ballpark £12-14k inc battery. Install looks reasonably straight forward. What is the max loading of the flat roofs?
Batteries bring the payback forward significantly by increasing the self-consumption and allowing you to charge them on off-peak rates.
 
Last edited:
chris1012 said:
I am early onto my PV journey and after some initial
What would be a realistic price for the following?

If the costs were too high, for the ideal setup, would it be advisable to install the panels and inverter now with wiring setup for future purchase of a battery?

Click to expand...
Are you intending to use different sized panels?

If going without a battery it might be worth adding in some east/west panels to maximise morning and evening light.

With E/W you can also consider a W pattern to maximise the number of panels for the space.

The optimizers would need to be used because your panels are all at different angles.

Have the installers said what method they'll use to attach them? I have a similar flat roof with panels on, and my biggest fear was penetrating the membrane and it leaking.
 
Last edited:
Mercenary Keyboard Warrior said:
So the battery usage test is complete.
I started at 3am, and it finished just before 2pm.

It recorded yield of 8.9kwh, but I miscalculated the discharge and it wasn't empty by midnight so approx 0.2kwh of yield was included before the batteries charged to 100%.

As such yield from 100% to 10% SOC (90% usage) was 8.7kwh!!!
I accept there will be some conversion losses, but thats 79% of quoted useable.
To be honest if I was achieving real world 10kwh vs 11kwh quoted I would accept that, but 8.7kwh against 11kwh quoted is not on.

Bounced back to installer, so lets see what they say this time.

Luckily the sun is now out and 4.3kw from panels. Hopefully a couple of hours and I will be on PV and stored PV until I can recharge tonight.

Will stick a screenshot up later.
Click to expand...
sorry if missing a post with this but......... are you saying your battery is 11kwh?

if so 8.7 may not be that far off. my battery is 7.2kwh and i only get 6 out of mine, the bottom 20% of the battery is never discharged due to protecting the health of the battery.

if your battery is 11kwh then 8.7 give or take would show similar ratio to my output on my battery. (20% off 11kwh is 2.2, which would leave a max usable capacity of 8.8kwh.)
 
Last edited:
bigmike20vt said:
sorry if missing a post with this but......... are you saying your battery is 11kwh?

if so 8.7 may not be that far off. my battery is 7.2kwh and i only get 6 out of mine, the bottom 20% of the battery is never discharged due to protecting the health of the battery.

if your battery is 11kwh then 8.7 give or take would show similar ratio to my output on my battery. (20% off 11kwh is 2.2, which would leave a max usable capacity of 8.8kwh.)
Click to expand...

Nope battery is 12.3 with 11 quoted as usable (90%)
 
https://www.youtube.com/watch?v=UJeSWbR6W04 he averages around 100-200kWh a month ? and i average 300kWh a month? wtf

I dont have a air con or charge a car! I just have some computers, coffee machine, washing machine, fridge freezer etc, nothing fancy. I dont even have my surround sound setup for my TV which is a 42inch bog standard TV....

I work from home though but i use dual screens and a laptop only....
 
now i am no longer mining i use around 4250kwh a year (this will go up now as i have an EV but right now am not charging at home).

I must admit i am not sure why i use so much (thank god for solar and battery as this has massively changed my bills)

we have a kid so the washing machine and tumble drier gets a lot of use, but its an A rated washer and a heat pump drier.

yes our TVs are 70 inch and 65 inch but they use far less energy than our old sets which were much smaller.

my games PC has an RTX 3090 in it which is thirsty but now i am not mining (i stopped June last year so can work out an accurate yearly use without) it is probably only on for 5 or 6 hrs a week (and we are only talking 600w/h even then.

our shower is used every day multiple times a day, but that is gas heated.

so as good as our house is for not using gas, i just do not know were our electricity use goes. (3kw electric heater in my home office/games room but i use that really rarely and only for short periods)
 
bigmike20vt said:
now i am no longer mining i use around 4250kwh a year (this will go up now as i have an EV but right now am not charging at home).

I must admit i am not sure why i use so much (thank god for solar and battery as this has massively changed my bills)

we have a kid so the washing machine and tumble drier gets a lot of use, but its an A rated washer and a heat pump drier.

yes our TVs are 70 inch and 65 inch but they use far less energy than our old sets which were much smaller.

my games PC has an RTX 3090 in it which is thirsty but now i am not mining (i stopped June last year so can work out an accurate yearly use without) it is probably only on for 5 or 6 hrs a week (and we are only talking 600w/h even then.

our shower is used every day multiple times a day, but that is gas heated.

so as good as our house is for not using gas, i just do not know were our electricity use goes. (3kw electric heater in my home office/games room but i use that really rarely and only for short periods)
Click to expand...
Well here is your problem
 
quick question ......... which i could probably google but maybe someone here knows too.

so we have a solar install and battery. IF we buy more storage we have to pay vat on the battery.

however if you install solar panels the battery is VAT free....... Does anyone know if there is a minimum amount of solar to qualify for vat free? i am sure there is room on my roof for 1, possibly 2 more panels, and if that made a possible battery upgrade VAT free its a total no brainer.
 
bigmike20vt said:
quick question ......... which i could probably google but maybe someone here knows too.

so we have a solar install and battery. IF we buy more storage we have to pay vat on the battery.

however if you install solar panels the battery is VAT free....... Does anyone know if there is a minimum amount of solar to qualify for vat free? i am sure there is room on my roof for 1, possibly 2 more panels, and if that made a possible battery upgrade VAT free its a total no brainer.
Click to expand...
Installer fees and scaffold costs will wipe out any 20% savings I think.
 
You must log in or register to reply here.
Back
Top Bottom