The Solar Thread

Sounds fair to me if it includes scaffolding

Does the following indicative quote look ‘fairly average’ to those that have had installs or quotes themselves? It’s from Octopus Energy. 4 bedroom 80s house, link semi detached, reasonable insulation (cavities & loft), no RV. Location is North East England. Roof is NE-SW pitched on both sides. (if that helps 🤷🏼‍♂️). TIA

Solar Panels: 12 panels (1.7m x 1.1m)
Micro-Inverters: 12 Enphase micro-inverters (1 micro-inverter per panel)
Battery: 1 Enphase 5kWh battery
Total Price: £9,829
Inclusions: Scaffolding, installation, and all electrical systems required for operation.

Whats you daily energy consumption? Do you need micro inverters any shading on roof? I’d get more battery  I have 10kwh and wish I went for 15. Where are batteries going? As  loft installation is no longer recommended.

Get more quotes to compare.

as above, a larger battery gives you more flexibilty, and the ability to export at beneficial times

slightly moot if you go intelligent flux for example though

Also, check the warranty of the kit to give you the peace of mind

I have an 8.7kW modular Foxess battery. Prices have come down significantly so I may buy another module. 5 is a bit on the small side I would go closer to 10 or so but depends on a number of factors. Going bigger is more expensive and if (like me) you can feed excess into water heating, car charging or back into the grid then storage is really only required to ensure you are not paying too much per kW in the winter. This time of year I dont even need to charge my battery on the low tarif overnight with an 8.7kW battery. Any feedin is at more than I paid overnight. Getting an ASHP next month so think the extra kW will be useful for that.

Another +1 for a bigger battery – we had quotes ranging from about 4kwh to 9.5. Ended up with the 9.5 which is just about enough for a dull winters day. If you’re out all day and just want the battery to get through the evening peak then you might get away with something smaller.

Also worth thinking about how you’re going to manage it post installation – I’ve ended up jumping feet first into Home Assistant which fortunately plays nicely with my GE kit, but even if your going down intelligent flux you’d need to be sure your kit is compatible (which it should be if the quote is from octopus but worth checking,)

Grand – thanks everyone. Just really sounding out costs vs benefits etc at this point, but some really good pointers for me to explore further. Having said that, most of what you responded with looks like a foreign language, so I’ll no doubt be back with more questions 😂

Immersion update.

I’ve just purchased a Sangamo programmable time clock  that’ll let me heat water at the cheap overnight rate.

Total cost £100.

I may install an iBoost or something similar in the future.

The added complexity I have is that only the downstairs is fed from the hot water tank, which is connected to the now redundant solar thermal, anyone know a company that’ll service this in Central Scotland.

I know Octopus are the main supplier for most on here but has anyone joined Eon?

they do a fixed export price of 16.5p for import customers or up to 40p if you get your system installed by them.

I’m interested in the Drive tariff that gives 7 hours cheap (6.9p at the moment) between 12 and 7am, 30p for the rest of the day, 63p standing charge.

Our winter usage is pretty high (up to 80kwh) but it’s almost all heating and hot water so we can shift the vast majority to off peak, plus charge the battery. Unlike octopus, they don’t explicitly rule out non-ev owners in the T&Cs. Have emailed to ask if it’s possible.

@giant scum if you want an iBoost let me know. I am having an ASHP fitted as we speak and the iBoost will be surplus to requirements by the end of the week.

@surfer hey that’d be great.

Think my mail address is in my profile.

@giant_scum Sent you a message in your profile.

So – how’s everyone doing?  Has the novelty worn off?

We’re pretty much at the mid-year point and the yield isn’t looking as good as least year, but it’s still good. Looking at the figures, I think we’ll be down around 700kWh based on last year with the extraordinary May and June which were nearly 870kWh each (this year 682kWh in May, 430kWh in June so far, so looking better).  I’ve left our batteries to charge on the off peak rate every night as the difference between off peak and peak is less than 1p/kWh and I figure we’re helping with Grid demand by exporting in the normal window.    Typical import is around 4-7kWh.

The twin RESU Packs are doing well having been upgraded in January, but I still have the annoying 70A max limit on the twin packs which isn’t there when using a single pack, directly connected to the inverter…I can’t get any support from LG.  6 months to reply to an e-mail and their response was “do you still have a problem?”  Twits.

it looks like batteries are approx £1500 for 5kwh – how does the ROI look for 5kw vs 10? It looks like you lose ~10p for every kwh you push back to the grid and consume later, and battery efficiency is around 80% so I guess you need to export around 19,000 kwh to break even. I’m not sure how common it is to be exporting if you already have a 5kwh battery (I’d assume uncommon in winter, fairly common in summer?)

We switched to octopus in the middle of may last year so my export data started then.

This year both the amount of production (27% down!!) and export has gone down, as well as the price we get so the credit going into next winter is going to be significantly less at this rate. This is the main reason why I’ll be looking to cash out and move to E.On’s cheaper overnight tariff in the autumn I think.

Import is higher this year as we moved to agile so when it goes below about 12p overnight, I charge the battery and heat the water etc. It’s annoying when there are afternoon price plunges (went to -8p last week), because if the sun is shining, I still have to burn through up to 6kw @15p, before I can get to the cheap rate juice

15 May – 15 June  23 –   Production 1520 kWh

exported 1006 kWh (@ average rate of 26.2p)

imported 130 kWh ( @ 21 p)

15 May – 15 Jun 24 – Production 1120 MWh

exported 819 kWh (@ average rate of 19.8 p)

imported 373 kWh ( @ 10.3p)

(10kWp E/W split, 10kWh battery)

quite sobering looking at the figures!!!

We were with Eon over winter for just import, not export. Their cheap rate was cheaper and longer than Octopus Go that we were on previously. The cheap rate finishing at 7am was great for morning electric heating and having the washer run during the cheap rate but not sitting there for hours afterwards.

The rates were good, but Eon is much less open than Octopus with their data which annoyed me. With Octopus you can find out exactly what you’re using and what they’re charging you within a day, the bills are very detailed, you can have confidence that it’s all working properly and the costs are what you expect. With Eon there’s nothing; you get a bill occasionally that has one number for peak and one number for off-peak and that’s it. If something wasn’t working for whatever reason and you weren’t being charged what you thought you were you wouldn’t find out for months and would have no way of checking it anyway.

We’re back on Octopus for their better export rates over summer but I’m not sure what to do next winter yet. Moving back to Eon would probably be cheaper but the switching process and their lack of data openness makes me wonder whether it’s really worth the aggravation.

We have produced 1771kwh this year so far.

Exported 780kwh so far.

It’s been a poor year for sure so far compared to the previous two years couples with energy costs coming back down. Still we are on track to be covering all our electric for the year(no electric car)

The standing charge increase has been a killer though.

2758kWh Generated

1877kWh Exported

1670kWh Imported

At 16.1p/kWh export (average) = £302,

Import is 14.2p/kWh = £237

Standing charge (£0.61p/d) YTD = £103!!!

We’re £68 in the red so far this year.  The Standing Charge really sucks.

I got a quote yesterday

6.090 kW Total Solar Power
14 x 435 Watt Panels
4,178 kWh per year
4.3 kWh Total Battery Storage (foxess)

11.2k

Think we use about 3.8kw – 4 / year. No electric car and gas cental heating. IN a new build property (3 years) with good insulation. New to all this so trying to get as much info as possible.

Monthly DD is at a token £10 just now with a £120 credit in account. The export covers my monthly bills for G and E

@ttickydisco I’d suggest looking at bigger batteries – if you’re using 3800kwh per year that’s more than 10/day on average, probably using more in winter when generation is also lower. A bigger battery will give more flexibility to charge off peak and avoid paying for higher rates during the day.

important spec missing from that quote is – what size is the inverter .

I wouldnt get too hung up on batteries – just be sure where ever you site them you can fit more units in .

you will want more and you’ll save vat having them fitted that the start BUT if the budgets set –  i wouldnt prioritise it over panels .

More panels = more power when the sun isnt great

you will want more and you’ll save vat having them fitted that the start

Batteries on their own are VAT free now as well, since April I think.

They are. But you’ll find that you need to employee a tradesman to plug them. In to realize that.

it’s cheaper to pay the vat than pay a man.

Been looking at adding another 5kwh to my set up. 1700 quid to buy vs just shy of 3000 to have it fitted.

You only get it vat free through a vat registered installer.

6.090 kW Total Solar Power
14 x 435 Watt Panels
4,178 kWh per year
4.3 kWh Total Battery Storage (foxess)

That doesn’t seem particularly good value for money to me. Powerwall 3 is now on the market and provided 11kWh of storage for £5000, and full off-grid capability. 4.3 kWh of battery in a Fox system is closer to 3.8 kWh in reality, or less depending on temperature and accounting.

You can get an all-in-one Fox system with 10.4kWh of battery storage (which is about the size of a thin fridge-freezer) which will live inside or outside for £3,200 ex-VAT. It will also provide 6kW of off-grid capability depending on how enthusiastic you are about doing some rewiring.

Fox system has the advantage of force discharge to the grid during peak times (eg when Octopus were paying £2/kWh for savings).

Myenergi Libbi will provide 10kWh of more expandable storage for more or less the same money.

Avoid Growatt – their battery discharge and charge capacity is capped, the app is terrible, and the inverter itself is difficult to configure (it’s a system where you have to go by parameter number instead of name).

My strong advice now that prices are falling is to not go less than 10kWh of storage.

Powerwall 3 also has integrated inverter I think, so you don’t need a seperate inverter. Saves cost and much more efficient. On a circa 40kwh day we lose around 1.5kwh between the solar edge inverter and the Tesla (measuring what each thinks has been produced)

So, fellow iboost users – we are going on holiday for 10 nights. Do I leave the iboost on so it keeps the hot water tank (300L) hot, should require minimal energy? Or. Turn it all off then have a mammoth heating sessions when get back? Not sure which will use less electric. Not that it really matters.

If your roof has shading, micro-inverters can help. You might want a bigger battery; I have 10kWh and sometimes wish I had more. Make sure to place the batteries properly since loft installation isn’t recommended anymore.

Not sure which will use less electric. Not that it really matters.

Bit of a late reply but: turn it off.

Your “mammoth heating session” will replace the heat that it has lost over ten days. Keeping it hot means replacing the heat as it loses it. The rate of heat loss is proportional to the difference in temperature between the hot water and its surroundings, so keeping it hot means it’s losing heat faster. You’ll use a lot more energy keeping it hot than letting it cool and then reheating it when needed.

Yeah. Thats what I concluded @pdw so turned it off!

Recently had our ASHP installed so with our PV and 8.7kW of battery I have moved to the Octopus Cosy tariff and monitoring over the next month or 2 before deciding on the purchase of another 4kW of storage at around £1k before the winter. At the moment the 3 low cost charging sessions a day plus a lot of solar combined with no heating requirement means I am exporting more than I am using most days. I suspect once the weather gets colder the battery may struggle to meet the demand between the 3 low cost charging periods.

Bit of a late reply but: turn it off.

What am I missing here?

Doesn’t the iBoost use spare solar generation to heat the water (the same as my Immersun)?

If so why would you ever switch it off?!

They use hardly any power and by switching it off you’ve got to reheat the water with imported power. Madness!!

probably turn it off, because its cheaper to heat with gas and export the electricity and get paid

probably turn it off, because its cheaper to heat with gas and export the electricity and get paid

In which case they’re pointless.

Quick question for those on Octopus.

I’ve been with them since last February, If I want to withdraw credit from my account I have to phone them. I have phoned 4, possibly 5 times and asked them to allow me to do this online, they have told me they will set it up each time, but it doesn’t happen.

Has anyone else had this issue? I’ve never been in debt to them.

Also it takes several days to reach the bank account, one time I had to phone back a few weeks after as I hadn’t recieved a payment. They were able to do it almost instantly on that occasion. How long are you waiting when requesting withdrawals?

Your “mammoth heating session” will replace the heat that it has lost over ten days. Keeping it hot means replacing the heat as it loses it. The rate of heat loss is proportional to the difference in temperature between the hot water and its surroundings, so keeping it hot means it’s losing heat faster. You’ll use a lot more energy keeping it hot than letting it cool and then reheating it when needed.

whilst this is technically true, if you’ve a modernish tank it costs so little to keep it running as to not be worth the faff on being really on top of it – the total loss of heat per day on ours is well below 1kwh – so its losing < 5C per day. over 10 days the average temp would be something like 40C instead of 60C, so you’re saving something like 5kwh total, or a quids worth of leccy.

probably turn it off, because its cheaper to heat with gas 

Great. Where do I sign up* ?

*Oil heating user – with a tank with electric element and solar thermal coil…..

I take £500 or so out every six months. Never seems to be an issue, I just email them at hello@octopus.com and they process it within a day or two.

I’ve never reached a substantial surplus with Octopus.  I pay £25 a month and the solar sorts the remainder of the year on around 6000kWh of annual use.

In which case they’re pointless

Yep. They made sense for the old feed in tarriffs where you got paid regardless of whether you actually exported or not.

Even if using it makes sense because your export rate is lower than the equivalent gas/oil price, it still makes sense to switch it off and sell your electricity if you know you’re not going to use the hot water.