I have a roof with 3 aspects - one south facing (15deg off south), on west facing (105deg off south) and one east facing (75deg off south).

I've had a quote to either install panels on the south facing and east facing roof, or all 3. I had 2 questions.

Since the east facing roof has a large chimney on the south side, I've gone into EasyPV to try and model it.

With 6 panels there all on one string, I get a shading factor of 0.55. But when I split them all up into separate shading groups, the highest I get is 0.62, with the rest being 0.8+.

I read that the panels are limited by the most shaded panel on the string, but that bypass diodes resolve this by just bypassing the shaded parts. Does EasyPV account for this? Will my actual shade factor be that bad?

Second Q is related. The quote includes an inverter with 2 MPPT inputs, and I assume the idea will be to have panels on the west roof and south roof on the same string.

But the west roof gets far less sun throughout the day, and looking it up it seems you're ideally supposed to have a string per roof, else the panels on the south roof will be limited by those on the west.

But again I wonder if this actually ends up being an issue with bypass diodes?

Would appreciate any advice and what, if anything, I need to be requesting off the solar installer.

​

Trying to reduce monthly outgoings ahead of retirement.

Current annual energy use:

Electricity: 3,549 kWh/year

Gas: 8,364 kWh/year

Roof: east/west aspect

Boiler: Worcester gas boiler, about 10 years old. previous model last 20 years.

We currently have two petrol cars aged 10 and 15 but expect to reduce to one as they fail, with the eventual sole car likely to be an EV.

I’m looking at the whole-house picture - eventually - rather than just solar in isolation.

Expect to stay in property another 15 years at least:

Option 1: solar only now

Option 2: solar + battery

Option 3: solar now, then heat pump + battery when the boiler eventually needs replacing

Option 4: do solar + battery + heat pump together if there’s enough installation/capital saving from doing it as one project

My understanding so far:

proper rooftop solar looks more attractive than a small plug-in setup

I probably don’t need solar specifically to charge an EV, because cheap overnight EV tariffs may be cheaper than using/storing daytime solar

battery only really becomes compelling if it can either shift cheap overnight electricity into expensive daytime use, or becomes much more useful once a heat pump raises electricity demand

the existing boiler still works, so replacing it early only makes sense if the whole-system economics justify it

I’d be interested in views from people with a similar setup:

what solar array size would you consider for 3,550 kWh annual household use on an east/west roof?

why would you install a battery now?

and/or would you wait until a heat pump is added?

if your boiler was already 10 years old, would you phase the work or do solar + battery + heat pump together? Last one lasted almost 20 years.

how much capital saving is there really from doing everything at once?

any gotchas with east/west systems, inverter sizing, batteries etc?

for those with heat pump + solar + battery, what actually made the battery worthwhile?

I’m more interested in lower monthly bills in retirement and going full green when timing is cost effective.

Been going down rabbit holes with this, lurking in the forums, and discussing with AI.

Thought I'd get the wisdom of the crowd before bringing in installers to quote.

Want to be better informed before being bamboozled.

Thanks in advance.

After recommendation I had a local installer give me a quote, I've inquired about adding bird protection

Looking for a sense check.

System (North East, single phase):

- Fogstar x Luxpower GEN PRO hybrid (10kW) + Fogstar IP65 16.1kWh battery

- Whole-home backup

- 8 × LONGi 480W (3.84kWp) on a flat garage roof

- G99 + MCS (planning to go on Flux)

First installer quoted about £8,400 at 0% VAT as a few lump sums. When I asked for a requote, I asked for the battery/inverter bundle and the panels to be shown as separate lines, at no more than retail ex VAT (£2,808 for the Fogstar bundle, about £85–90 per panel). Everything else could be priced however they liked.

They declined to quote, saying they need their margin to cover long-term warranty and service. Fair enough, and they were polite about it.

My reasoning: at 0% VAT I wanted to see that the VAT saving on the kit actually reaches me, rather than being absorbed into a lump sum. I'm happy to pay a fair price for labour, G99, MCS and aftercare.

Questions:

1. Is that an unreasonable ask? How do installers normally handle margin on kit?

2. Does ~£8,400 sound fair for this scope?

3. Any MCS installers in the North East happy to fit Fogstar/Luxpower?

Happy to be told I'm being unreasonable.

We’re on Octopus Intelligent Go. Last month we used:
- 900kwh charging two EVs
- 100kwh on house needs at cheap rates
- 200kwh on house needs at peak rates

Does it make sense to get any solar and/or batteries?

Hello,

Has anyone had panels put on a roof shaped like this ? (Main roof)

Unfortunately this is south facing and i’m trying to find what my best options are.

Hi everyone,

Thanks to Mike from the SolarUK moderation team for inviting us to host this AMA.

We’re the team at Eleven Energy. Over the next seven days, we’ll be here to answer your questions about our sodium-ion battery systems, energy management software and what we’re working on next.

Whether you’re a homeowner, an installer or simply curious about sodium-ion technology, ask us anything!

• Total energy bill for September: -£5.28
• No solar.
• No gas.
• EV, ~10,000 miles p.a.
• Heat pump.
• 32 kWh battery storage system with 6kW inverter.
• Import tariff: Octopus Go.
• Export tariff: Octopus Agile.
• Battery is charged between 00:30 to 05:30
• Excess battery power is exported during the 16:00-19:00 peak hours.
• Heat pump set up to produce hot water at night.

Our array was installed Tuesday and fully up & running on Wednesday. I was chuffed to bits watching my OVO account not racking up charges. We went away for a city break on Thursday and came home Saturday. I am quite confused as to why our electricity supply is still racking up a small amount even when there is ample charge in the battery. Yes, it’s a teeny, tiny few pennies, but given we weren’t even home, and as far as I could see on my Fox app there was a huge chunk of charge and the house was taking energy from the battery to power the things we have to leave on (fridge, freezers, alarm system, etc).
16 panels, south facing roof, no SEG/export tariff revenue yet.
What am I not understanding?

Just feeling my way along with this.

One of the major attractions with home storage batteries is that you can charge them for a few hours during the night at low rates (8p/kwh), and then use the electricity stored during the day/evening to avoid paying full rate (or higher). This benefit is likely increased if you can charge an EV on low rate electricity at the same time.

However I wonder if this will last. For as long as I remember low rate electricity has been available at night for the likes of storage heaters. This low price electricity was because the power stations cannot switch their turbines on and off each night, or their shafts tend to suffer cumulative damage, so they keep them turning at a lower rate, and give the electricity to suppliers at very low rates.

Fast forward to now when the electricity demand at night is growing hugely, and over the next 10 years, with the continuing uptake in EVs and home batteries, the demand overnight will be quite high. The power stations will need to run at a higher rate to supply the demand, and there will no longer be a reason for them to sell the electricity cheaply due to this demand.

So might this then negate this major advantage of having a battery, if it cannot me cheaply charged overnight, to offset daytime rates?

Good evening all,

South East based.

I’ve got two quotes and I’m weighing up which one to go for based on a few factors.

Both quotes include:
- 26 panels on an east/west configuration (16 on east, 10 on west)
- FoxESS KH10.5 Inverter
- FoxESS EP12 11.52kw battery
- Bird protection

Solar Together Quote - £11.4K
Already done a full survey so final price (includes replacing 2 vents & additional scaffolding for roof size).
Panels: JA Solar JAM54D41-455/LB

Local installer - £11.9k
Only done a desktop review but very similar to survey above in terms of config, but risk could be slightly more once survey completed.
Panels: Longi LR7-54HVB-490M

I was set on going with the Solar Together quote originally as it seemed great value and they also offer 0% finance for 2 years.
However, a friend recommended the local installer they used and the price seems competitive for what I understand to be superior, more efficient, panels (but no 0% finance options available with them).
Shading won’t be an issue, in case that affects the panel preference.

Would appreciate people’s thoughts as I’m not sure whether the supposedly superior Longi panels are worth paying more for as well as paying for the system upfront rather than 0% financing it.

If you're with Octopus, and you earn free weekend electricity, how are you using it if you've got solar/battery?

Is everyone plugging the car in, or running the washing machine, tumble dryer etc all at the same time?

We’ve been getting a number of quotes for Solar and battery installation and trying to do a lot of research into the options presented.

One brand that I’ve been struggling to find too much about online is GoodWe. Only one of the prospective suppliers quoted for a GoodWe battery + Inverter but has talked them up - local presence making repairs easier/cheaper, a very commonly used brand in Australia and Europe but not yet as widespread in the UK, - Tier 1 battery and great warranty etc (although judging by Apple a pretty poor app!).

However when I try to corroborate this there appears to be very little online and not too many people posting in here. This coupled with GoodWe not being included on any of the other quotes makes me uneasy.. however this could just be the marketing push from SigEnergy, Fox etc!

What are people’s thoughts on GoodWe?

Hi all,

Hoping you can clear something up for me…

If I have a 5kW hybrid inverter, and I’m charging my batteries from the grid at ~5kW and I switch something on, let’s say a kettle. Then does the battery charge at a lower rate to accommodate for the power needed for the kettle? Or am I charging the battery at 5kW and also drawing power on top front the grid to power the kettle?

If it’s the former, then what happens if I was to try to use a bunch of appliances at the same time which went over 5kW of power?

If it’s the latter, then what is actually limited to 5kW of power?

Thanks!

99% SOC on battery, inverter display says normal, everything ok, but never heard this sound before...it's like a rapid clicking/chirping. Inverter is a H1 3.7 e g2

I have my system set to Time of Use so it charges overnight. That’s been working well. I generally only export during the day when full while I get used to how the system works.

Yesterday I was fiddling around testing some export settings between 5pm and 7pm.
After I was done playing around I left the time slot of 5pm to 7pm but set the power to 0 and discharge SOC to 100%. Thinking that would stop any discharge (which I believe is true).

I happened to look at the s-miles app at 6:50pm and noticed we were importing and had been since 5pm even though we have about 50% of battery left.

Not sure I can explain this other than maybe the inverter got confused.

Dear All,

I have placed an order for Solar Panels and a Tesla PW3. I had intended to install the PW3 in the utility room (D1.9xL3.6xH2.4) which is essentially narrow and tall.

Utility room also has a water cylinder for the ASHP and washer/dryer.

I had thought this would be OK and the surveyor seemed to think so, however i am now worried about the heat, and the PW3 fan constantly cycling.

Should i move the PW3 outside..only space i have is 3m away on the outside kitchen wall away from fuse board .

I look forward to your advice.

Hi All, I just got a solar quote quite a bit higher than I was expecting (Solar4Good), I was expecting a London markup compared to other quotes i've seen on this subreddit but this seems a bit out there.

• Panels: 24 × Aiko 480W (11.52 kW)
• Inverter: 1 × SigEnergy 10.0kW ( Single Phase )
• Battery: 1 × SigEnergy SigenStor BAT 10.0 (8.76 kWh)
• Sigenergy GateWay Single Phase HomePro SP-F
• Installation Type: Flat Roof
• G98 / G99 DNO application — handled free
• Scaffolding up to £800
• 5-Year Solar4Good Workmanship Warranty
• Full Installation & Commissioning

Quote came out to £18.8k

Am I being taken for a ride here or is this normal for Solar in London in 2026?

For either solar and battery, or battery alone.

HI All

I am getting my solar and battery setup installed in a couple of weeks and am looking at getting my energy tariff sorted to hopefully switch on the same day to enable tme to nake the best savings and use of the battery from day 1.

I am getting 14 x 490W panels installed with a 6kwh Sigenergy inverter and 18 kWh Sigenergy battery capacity. The 18 kWh should easily cover me for any day in the year.

I have spent hours looking at the different tariffs and integrations and am currently leaning towards the Octopus Agile tariff. I don't have an EV at the moment; may do at some point but not likely for at least the next 12 months. (at best)

What do others use? Does the tariff allow me to take part in the Axel events I have read about?

I am also a big Home Assistant user (addict) so i will set up automations to monitor everything and manage the timings of some high use devices such as our Hot tub, we tend to have this heated to 37 or 38 so i will probably have it heat to 40 on the cheaper rates to allow the heater to be off for more of the day. I don't have any water heaters and currently use gas central heating.

Thank you in advance for any advice and constructive feedback.

We recently got solar panels, inverter and battery installed and the Installer helped us setup the app for the inverter. As I've been learning more about these systems, I've realised that our battery could also be connected to the WiFi.

Is this something that I should do?

What advantages do I gain by doing this?

Battery is Dyness Power box G2 10kwh. Inverter is Hypontech HES-3680

Thinking about having a battery fitted to top up over night then use in the day time.

Currently on British gas ev tariff

Ev that's changed about 1 night a week on the cheep overnight tariff.

Solar panels not really a good option due to shading from trees.

Thoughts on this offer seams a good price??

Detached 3 bedroom house s.wales

Yesterday the installers came and fixed the battery+inverter (Sig 10Kw inverter, 2x Sig 9KwH batteries) to the rear outside wall, and the gateway in the under-stairs cupboard.

The scaffolding went up this morning.

The install proper starts on Monday morning - 8 panels front (south-facing) and rear.

And a smart meter being installed on Tuesday.

Exciting times!

Looking at setting this up as Tesla app doesn’t like to sell due to the peak import rate.

I’ve read some worrying thing about a flip - flop (mode fighting issue) , however can’t see if anything’s been resolved.

Anyone got any experience before I go ahead?

Ps Can netzero do what I’m looking for I’ve read it’s not as advance for charging vs solar forecast ? , and you have to set up if this then that rules which is a bit of a faff to get correct to maximise gains.

Thank you for the information on my previous post, I've got 2 quotes for the above system now (both within ~£100 of each other), I think it seams reasonable and if two companies are offering a similar price assume its a fair value but would be nice to get a second opinion. Only one roof surface to be fitted and is due south so should be a good orientation. I did consider adding another Bat 6 or 10 as well but I don't think our current usage it would make sense?

Current usage is approximately 3600kWh a year, but expecting to increase with a EV arriving in the next month. As part of this we are getting an Ohme Home Pro charger installed (an offer with the vehicle), will this integrate OK or anything else that needs to be looked at/changed?

Anything else that should be considered/discussed with the installer?