It’s Huawei, you think it’s going to the grid but really your giving China free energy 😉
In all honesty after my experience with Huawei enterprise level networking kit, there’s no way I’ll every buy anything of theirs. Ok the support was good if you class sending out software engineers to rewrite their code on the fly as the products don’t work as advertised (or as tendered) 😁
Ok the support was good if you class sending out software engineers to rewrite their code on the fly as the products don’t work as advertised (or as tendered)
To be fair, we've done exactly the same 😉
100A, that’s 23kW
not 100amp at 50v its not .
equally your car is likely NMC technology for its high charge/discharge/volitility (and thus combustability)
house batteries these days are LiFePo - which is much more suited to a permanent domestic setting
Ok the support was good if you class sending out software engineers to rewrite their code on the fly as the products don’t work as advertised (or as tendered)
Just reminded me, 20 odd years ago we were developing a new product and needed to test interoperability of an interface, so were hunting round looking for kit. I thought 'you can't go wrong with Cisco' so we bought a router and cards for standard X. Only when it arrived it didn't work, filed a support query to be told it didn't work, they sold a non working interface card which basically did nothing. They did eventually get it working, but in the mean time we used a Chinese cisco rip off* box (which had working SW)!
Bought in China, made in china, but ran iOS and only had an English interface!
What a great thread, some really useful info in here!
We're installing a 32 panel array with 7.5KW battery and car charger at the end of April. With the green technology discount in Sweden (20% on panels, 50% on batteries) maxed out for this year, we're thinking of adding modules to increase the battery capacity in 2024. Is this an electrician job or can I buy and install myself?
DIY for Fox batteries, don't know about others.
The battery is a Growatt, if that helps...? 😏 😁
32panel?! Blimey - in full sunlight that’s what? 13kWp?
LG aren’t quite plug and play…
You've got to make the most of the sun when it does shine in Sweden! The panels are split over east/west/south facing roofs so should spread the generation over the day, is the thinking anyway. 😏
Is this an electrician job or can I buy and install myself?
There are two aspects to that; how difficult is it, and what laws or other restrictions may apply. Are you interfacing your panels with the mains supply, or are they stand alone? Do you plan to export power back to the grid? In the UK, your system has to be certified if you wish to export, which means you need to use an installer who can provide the certificate. I don't know what is the case in Sweden.
Sorry, my original post was a bit unclear. The installation is all done by a company specialising in solar. The electrician or not question was only referring to the bolting on of extra battery modules. 👍
I think (but I may be wrong) that in the UK extra battery modules would still need to be notified and certified if you are exporting.
No, you can DIY extra batteries without restriction in the UK.
OK then, I stand corrected.
Can you mix and match battery manufacturers?
No. These aren’t dumb batteries, they have a BMS to which some inverters can talk. Most/all inverters need to know the model of battery they’re interfaces to. There’s no option for multiple types.
Technically, a G99 is submitted with a specification and wiring diagram which shows the batteries and their capacity. If it changes, you should update it. Whether anyone does or even if it’s a requirement, I don’t know, just that the specs for your g99 are technically wrong if you expand.
Morning Folkes, has anyone any experience with Libby battery / control systems. My local installer has put together my quote based on them.
Technically, a G99 is submitted with a specification and wiring diagram which shows the batteries and their capacity. If it changes, you should update it. Whether anyone does or even if it’s a requirement, I don’t know, just that the specs for your g99 are technically wrong if you expand.
Mine is incorrect, the installer filled in the wrong battery size. Not that anyone cares / will ever notice....
I haven't really put alot of thought into this and wondered what more experienced people's views were please.
I have 12 panels on a feed-in tariff in a East-West valley, they generate on a sunny day this time of year 10Kw a day but my house tends to use most of it. I guess it's not as perfect as it seems with key generation being over the middle of the day and majority of use being either end of the day, and height of summer likely being closer to 20Kw a day.
What would you do? - add a battery to capture it all to ensure that it smooths out the usage and provides a back-up at the same time? Any views on size of battery I should be considering please? I had thought of a solar iboost type thing but if I'm honest feel like the battery is a better option.
Thanks and apologies, i'm at the musing stage so willingly admit I haven't done any research!
What would you do? – add a battery to capture it all to ensure that it smooths out the usage and provides a back-up at the same time?
The battery will allow you to use 100% of what you generate and also charge at cheap rate overnight during winter, so you can use cheap electricity all day.
They generally don't provide a back-up unless you install extra kit as you need to isolate your solar system from the grid in the event of a power cut.
However, the economics of a battery are pretty marginal, a 10 kWh battery will cost you £5k+ and that's a lot of kWh of leccy to pay for itself....
NB We have a battery and it's great, but the cost doubled the overall installation cost, which pushes payback years out further and the amount it saves us is pretty marginal. Very 'green' (we don't use any peak hours leccy all year round), but not very cost effective...
We specced a 10 kWh battery and our daily usage is between 6 and 12 kWh (12 is when we do all the washing at the WE and tumble dry if it's raining etc).
Thanks footflaps, I appreciate the pragmatic reply. I anticipate there are some that make it work as hard as possible but I have a personality weakness that it would consume me so I'm keen not to become one of those! 🙂 It's why I've avoided going onto a variable rate tariff as i suspect it would end in divorce.
Maybe the cheaper iboost type device fits my needs that would divert excess generation into heating water would be a better solution. Least not because I have a hot tub to support but I'm not entirely sold on the idea of a lead for a submersible heater coming from the front of the house (where my solar generation meteris) and the back (where the dirty sex pond is).
When I originally specced our system, the battery made complete sense as the best export tariffs were offering 5-6p/kWh, so it made sense to store it to use later: it actually improved the ROI term from 11.5 years to 7.5years. Now with Octopus Flux, it's a MUCH harder proposition and I'm not sure it makes as much sense, or at least not for a massive battery. Maybe somethign small to keep you off the peak hours.
It’s why I’ve avoided going onto a variable rate tariff as i suspect it would end in divorce
We're on a dynamic tariff - Octopus Agile.
I've just set ours up to do a partial charge between 3 and 5 am, if the battery is below 60% and if not, do nothing. It hasn't charged now since the start of the April, but prior to that it would top up after overcast days, so we always had enough to get past peak hours (5pm-7pm) every day on the battery.
Initially I did use to look at the rates every day, but lost interest after a while.
Least not because I have a hot tub to support but I’m not entirely sold on the idea of a lead for a submersible heater coming from the front of the house
ex colleague of mine - in stonehaven scotland is maintaining his sex pond at standby currently with 2 flat plate solar thermal collectors on his shed roof
his solar PV provides the pump electric.
at this time of year he suppliments it with grid electric to raise it to in use temp.
by mid may it'll be pretty much standalone between the Thermal and PV.
He could have gone PV for the whole lot but it would have consumed all his PV generation.
When I originally specced our system, the battery made complete sense as the best export tariffs were offering 5-6p/kWh, so it made sense to store it to use later: it actually improved the ROI term from 11.5 years to 7.5years. Now with Octopus Flux, it’s a MUCH harder proposition and I’m not sure it makes as much sense, or at least not for a massive battery. Maybe somethign small to keep you off the peak hours.
I'm not sure that makes sense. I think of the battery as a capacitor. There is lot of low grade power in the 3-600watt above your base load coverage that would be wasted or only be supplementing load - you cant run a washing machine or dishwasher on that output but after a few hours you have gathered enough electric to cover a load. then in winter the ability to charge at the low rate and run through the high rate - low rate being 10-15pence lower than the higher rate.
Iboosts etc are the bit that doesn't make sense with the addition of flux - its cheaper to use gas than to heat using what could have been exported electric.
Yeah, but I have a wife who won't make the calculation. She'll just look at a badly stacked, only really half full dishwasher and start it regardless of the battery condition.
But fundamentally, I do agree that the battery smooths over the spots in generation caused by cloud/intermittent sun, but I'm saying that if the difference in export to import is only 10p through the majority of the day, The fact that I use 12kWh a day, shouldn't size the battery, a smaller battery, saving a ton of money makes more sense.
Say for example, my 13kWh Battery was £6800 and a 5kWh Battery was £3k. I need to figure out if that £4k is worth it. At 10p/kwh difference between export and import, That's 40000kWh worth of power I'd need to store to make back the difference. I'm not going to do that in 10 years, probably not in 20.
A 5Kw battery would, as you say act as a capacitor and get me through the peak period, thus making the best of the system without the massive buy in costs of larger batteries. I've got nearly 20kWh here now, but had flux been available in January, I might not have installed the additional 6.5kWh.
Thanks all, really good info. I forgot to mention I don't have a smart meter so the assumption made by FIT is that only 50% of what is generated makes it to the grid. I suspect where we win in winter we lose in summer so it's a fair arrangement.
Hmm, all I've worked out is it's yet another subject that's beyond my brain matter! 🙂
I don’t have a smart meter so the assumption made by FIT is that only 50% of what is generated makes it to the grid
We do have a smart meter, but Eon still work on the 50% assumption rather than using the data.
if the difference in export to import is only 10p through the majority of the day
A friend of mine is on (I think) Octopus Agile and Outgoing Agile - if he has spare capacity he can charge his battery at the lowest import and discharge at the best export rate. There were a few times over the winter when the import rate went negative; he was paid to charge the battery and then paid again to discharge it. I suspect it requires a lot of work to optimise it, either manually or setting software, so it may not be realistic.
I’m not sure that makes sense. I think of the battery as a capacitor.
Great way of looking at it. With Octopus Go, 4.6kW of solar, 5.2kWh battery, and an EV the average price I’ve paid for electricity over the winter is 8p/kWh. This did need some planning ahead with things like running the dishwasher and washing machine overnight though. Heat pump tumble dryer also made a big difference.
There were a couple of power cuts in the village, but the battery kept the oil boiler and freezer going (hard wired into the EPS port on the inverter), and the TV / lights on via a long extension cable. It’s actually easier and cheaper to protect stuff like the broadband router using a £50 UPS from Amazon.
Just applied for this years Solar Together scheme which is closing soon (Kent). Really wish I’d gone ahead with the quote I got a few years ago as I’m sure prices will have rocketed now due to demand etc. won’t get the price though until they do the auction mid-June.
Just applied for this years Solar Together scheme which is closing soon
tread carefully .
a quick sniff around the solar facebook groups and the solar together schemes often come up at astronomical rates as well as subject to sub contractor shoddyness......
like most goverment implemented schemes - it seems the the wee wee is extracted mercilessly.
Yeah, just applied for a quote at the moment. The price I got did a few years ago did seem keen. I did see a few posts on the local FB last year where people seem to have had their installs repeatedly delayed (after paying deposit) but possibly that was just down to huge demand (I know they closed the books on the scheme last year as oversubscribed). Will defo investigate thoroughly before parting with any cash!
often come up at astronomical rates as well as subject to sub contractor shoddyness……
I would think it's less likely to be over priced if the scheme is well run and gone to an auction.
I had quotes from a local installer (Chiltern Solar) and Solar Together Bucks. Chiltern Solar were about 10% cheaper and seemed more clued up.
Thing is there must’ve been hundreds if not thousands of ST installs locally but can find very few reviews etc online either good or bad. Might have to pop up a Q on local FB page.
This guy not happy though 😬
https://forums.moneysavingexpert.com/discussion/6217540/solar-together-kent-good-scheme-good-quote-for-a-12-panel-system-avoid
yeah will defo get some quotes in from local and/or recommended companies. I’d never use a plumber/electrician/builder etc without a recommendation so this isn’t any difference really!Chiltern Solar were about 10% cheaper and seemed more clued up.
This guy not happy though
You always expect those who are unhappy to make more noise than those where it all went as expected though, so if you go looking for complaints you just find confirmation bias....
I’d never use a plumber/electrician/builder etc without a recommendation so this isn’t any difference really!
Although if you're going through a managed scheme, you would expect that the organisers would have done some due diligence and have the ability to hold the supplier to account on your behalf...
Yeah I appreciate that. Reviews on Trustpilot are fine, on the whole. I suspect the key thing is which company has been contracted to do your actual install though, rather than the administrators of the scheme!
Currently waiting for Energy Saving Trust loan (£6k solar + £6k battery) - 11 panels going to go on roof and trying to figure out best battery option...
Daffy
Full MemberSay for example, my 13kWh Battery was £6800 and a 5kWh Battery was £3k. I need to figure out if that £4k is worth it. At 10p/kwh difference between export and import, That’s 40000kWh worth of power I’d need to store to make back the difference. I’m not going to do that in 10 years, probably not in 20.
A 5Kw battery would, as you say act as a capacitor and get me through the peak period, thus making the best of the system without the massive buy in costs of larger batteries. I’ve got nearly 20kWh here now, but had flux been available in January, I might not have installed the additional 6.5kWh.
I'm looking at pretty much this calculation at the moment - whether to go 5/10/15kWh battery when our daily usage is ~20-22...
looking at battery spec, some have 10000 charge cycles, some have >6000... thinking this needs to be checked for the 40000kwh worth mentioned above to check battery wont be goosed before it has paid for itself? 40000 / 5kwh = 8000 cycles so 6000-10000 is critical?
Do you just assume 1 charge per day or will it be charging once on solar and once through night? effectively halving the life of the battery?
My basic calc is that instead of electricity being 34p/kWh, it will be 12p, so 22p saving if run through battery x 90% efficiency / depth of discharge reduction? = 20p saving at today's prices...
5kwh battery x 365 x 20p = £365 return each year per battery?
Libbi 5kwh battery = £3200, therefore 8.7 year payback?
10000 cycles / 365 (once per day) = 27 year lifetime!?, though more likely to be twice a day?
Growatt is £2500 cheaper for 10kwh setup, £2100 for extra battery (i.e. £4600 more for the same capacity), less power in and out and >6000 cycles for the lifetime. Installer is pushing libbi as the much better system / work better with the app and zappi... more like a 5.7 year payback on the growatt if they function well enough?
Also looking at specs on foxx / pylontech / puredrive which have been recommended by other installers... quite a variety of cost / lifecycles / ratings
Looking back through my historic energy rates:
2016 - 10.21p
2017 - 12.33p
2018 - 12.37p
2019 - 12.37p
2020 - 15.09p
2021 - 14.88p
2022 - 27.84p
2023 - 33.91p
Will batteries continue to make sense for next 10 years? More chance of rates rising than falling or will wholesale market adjust to renewables?
more info on this please? (apologies if you've already given it & I missed it!!)Currently waiting for Energy Saving Trust loan
interest free loan over 10 years supposedly. "Home Energy Scotland application" ... - but their email has energy savings trust.... takes a bit of digging on google and then a nonsense half hour phone call with someone asking if you have energy saving lightbulbs etc - they then send you a code and a link by email, which you need to do the application.
Application needs a quote from an MCS approved installer - they have a list of people...
i invited 4/5 of them to quote - still trying to work out if the quotes are good value or if they are pricing to max out the spend of the loan.
one sent a "quote" = £6k for solar and £6k for batteries to get ball rolling and said they would send a propoer quote once we had desired spec in mind for battery and panels etc
thanks, will have a look! EDIT: looks like Scotland only for that one.
Will batteries continue to make sense for next 10 years? More chance of rates rising than falling or will wholesale market adjust to renewables?
the questions i asked my self is - what has the goverment done to secure lowering of energy prices - our infrastructure is ageing and sufficient replacement capacity is not yet in the pipeline it seems.
They have cemented in plans to increase consumption by significant multiple of current values ( electric cars and phasing out of gas heating replacements)
adjustment to renewables will likely take form of time adjusted pricing to suit the volatility of the generation.
the reading on all of those said batteries were a no brainer in my risk vs reward - and if im wrong - so be it - I'm still getting more use of my solar panel power than i otherwise would have.
one sent a “quote” = £6k for solar and £6k for batteries to get ball rolling and said they would send a propoer quote once we had desired spec in mind for battery and panels etc
I can see why, it filters out anyone who isn't in the right ballpark. Our system cost £12k and was pretty much split 50:50 between solar and batteries (panels are cheap, but labour intensive to install and need scaffolding etc). Batteries are easy to install, but are expensive.
They also need to filter out anyone who doesn't have suitable roof space and orientation e.g. if you're North facing, there's bugger all point installing anything...
Octopus users, has anyone tried switching between outgoing octopus and octopus go on a summer/winter basis. Wondering if I can have my cake and eat it. So get the better export during the high production months then force charge the battery for less in the winter.
Yep, you just need to stay on your tariff for 30 days. The gamble you take is that your good tariff is gone when you try to move back, but Octopus are surprisingly un-evil when it comes to this.
Just joined and gone more or less straight onto Agile. Waiting for an MPAN to start exporting. Will probably go onto flux when it comes through as the export prices outweigh the higher import prices i think.
My understanding is not that you have to stay on the tariff for 30 days, but that once you switch to a smart tariff, you cant switch to another within 30 days. you can go back to the standard tariff whenever if that's better for some reason.
I hadn't come across flux before this morning but it looks to fit better for us than go or outgoing. I think we can easily avoid the peak charges and the day time export rate is much nicer. Have signed up to that for now to see how it goes.
Hi solar thread peeps! I have to confess I haven't read all 20 pages, or would understand about 50% if I did. However I come with a question and I am sorry this has already been done. I live on a council estate in sunny south london. We are blessed with shallow south facing roofs and a row of garages with flat-ish roofs that get sun. What I need, on behalf of our tenants management firm, is a proper itemised quote and consultation, ideally for free, for installing panels and a worked out program fr how to manage the energey we produced. I have tried one or two local community enterprises but they aren't on it. There's around 350 residences, but even if we powered the office for free that would be a start. Please get back to me if you can help or know who can
I think there’s so much demand for solar at the moment it’s unlikely you’ll find an installer with the goodwill and time to do something more complicated than a standard quote. Although I’m not really sure from your post what you are looking for. Feels like there are complications like who owns the building, who pays for the installation, who benefits from the electricity generated etc.
Yep, you just need to stay on your tariff for 30 days
100% not the case when you port to them. It's just if your switching between their smart tariffs
I moved from OVO to octopus on April 4th. I was on flux incoming by the 8th once they had fully ported my smart meter.
Went live on flux outgoing last week also according to their emails.
April figures: 5.4kWp array, SSE facing, 30deg incline, 19kWh of battery storage, little to no shading.
597kWh generated. 510kWh used. 44kWh imported (3/4 of this was car charging), 157kWh exported. Power cost £13. Standing charge £15. No export payment 🙁
Currently moving to Flux, which for the amount exported this month would have netted ~£34 so we’d have been cash positive.
Bar for the 3 days of partial car charging and little bits each day (~0.2-0.7kWh from power switching) we’ve been off grid for the whole of April. Win!
We've exported 275kWh (of 514 production) this month and got paid 0 for it! Flux outgoing still processing (though to be fair the new smart meter was only fitting half way through the month).
Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW. Still trying to get battery profile control. I think this could help with the clipping as I think I could set it up to prioritise export more on sunny days so the battery charges slower.
Looking at the graphs the battery is worth it. Around 45% of our consumption comes from the battery, a greater portion than direct consumption!
Does anyone know of devices other than batteries that can be installed on the DC side (solaredge system).
Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW.
It's why some people fit things like the Zappi charger and Eddi hot water diverter. Otherwise it's an education thing - don't run the washing machine / dishwasher / oven simultaneously. I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.
Apart from using an electric hob it's quite difficult to exceed 3.7kW continuously, especially as the inverters are allowed to spike up to 4kW for short periods?
It's the oven + 5 ring induction hob that causes the spikes. In fact the hob in its own can pull more than that. Doing quite well at the other bits, have switched most dishwashing and all clothes washing to quiet usage periods.
Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW
bigger inverter would likely have been clipped by the batteries.
remember that if your making sun then most decent hybrids can do 3.6 from the solar and 3.6 from the batteries.
"
It’s why some people fit things like the Zappi charger and Eddi hot water diverter. Otherwise it’s an education thing – don’t run the washing machine / dishwasher / oven simultaneously. I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.
"
Not gonna lie - was having slightly cold feet over my Solar thermal install with the oil prices but at the end of the day - it will still be cost neutral one da + the tanks now in place.
got my batteries updated mid month so my utilisation is up now - with 5kwh only i found i had to charge in the 19pence period or i was out before the sun could catch up. New firmware and my batteries have stopped throwing errors and self limiting to 500w - solved by shutting down the second battery short term.
We got 406Kwh from our 3.6Kwh array for April - not had to import other than for our electric shower since my batteries were updated.
remember that if your making sun then most decent hybrids can do 3.6 from the solar and 3.6 from the batteries.
Is that with AC coupled batteries? Our battery is DC coupled, the AC output is limited to 3.6Kwh whether that is coming from the array or battery. It can output 3.6 with everything else going to the battery but that is only good till the battery is full. With very little load the battery appears to be able to take charge at whatever rate the array produces (have seen 6+).
I imagine we could get better consumption and generation with different settings but the solaredge all does not yet give that control.
Bar the 1st April, which was really dark, we've been 100% self sufficient last month. 372 kWh from a 3.8 kW array.
Still owed Octopus £5 though as our export didn't wipe out the standing charge fully. Had we been on their fixed 15p rate, we would managed to, so will change as soon as I can figure out how to - can't seem to find the option on their webpage.
@footflaps. The flux tariff may be even better for you as well export can be 20 or 30p
ah yes - mines AC coupled via a hybrid inverter.
I probably shouldn't be able to do 3.6 + 3.6 but im not going to complain about it......
Hmm maybe be a useful future enhancement to add a smaller ac coupled battery for the spike loads.
I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.
Ah, that's first on my list when we get panels. Dumping energy into our hot water tank is a clear winner. Will need to look up that switch
We don't have a hot water tank currently so dumping to water would have a high upfront cost.
Ah, that’s first on my list when we get panels. Dumping energy into our hot water tank is a clear winner. Will need to look up that switch
We haven't bothered.
The kit is nearly £1000, which is a lot of hot water and the fact it's going to be quite random and require us remembering it's been overcast, so we have no HW, so have to switch on the boiler to have a shower after a ride, would be a bit of a PITA.
Unless you have a massive solar array and live somewhere with no clouds, in which case I can see it working....
Flux has really changed the economics of solar/storage/thermal. Before it was almost a given that you should use as much power as possible, now it’s practically even to simply export/import unless at peak times.
Interesting tidbit. Yesterday, at its peak, solar power was contributing 9GW of power to the grid. Almost 30% of demand. Power was so cheap that we were essentially buying it from France at the cost of transmission.
yes ive just moved from bulb to octopus and they are giving me 15p per kw export. Im really happy with that. Not sure how long it will last though. How come its so much more than the usual 3-5p?
I fancy a water heater as the battery is full by 1pm so it would be used. however it seems expensive.
The kit is nearly £1000, which is a lot of hot water and the fact it’s going to be quite random and require us remembering it’s been overcast, so we have no HW, so have to switch on the boiler to have a shower after a ride, would be a bit of a PITA.
Unless you have a massive solar array and live somewhere with no clouds, in which case I can see it working….
It's not random to be honest. At one house we have a 4kwh E?W system and I'll soon be turning off the boiler completely as it easily does all the hot water for two of us throughout the summer period.
We've just been away for 6 days and the boiler didn't come on once.
At the other place we have just 3Kwh but it's S facing and it too does all the hot water from April to October - in fact there's isn't even a boiler there!
I may have to boost it twice each summer but that's only when we have a house full.
But £1000...Really? That's insane!!
ive just moved from bulb to octopus and they are giving me 15p per kw export. Im really happy with that.
Awww, sweet. My export is currently 60.25p/Kwh...... 😛
Sorry 😉
whats your on peak import?
whats your on peak import?
22p - still on a fixed rate until October.
Flux has really changed the economics of solar/storage/thermal. Before it was almost a given that you should use as much power as possible, now it’s practically even to simply export/import unless at peak times
Given we have many wet dank days with poor solar I can't get this to add up for me, currently on tracker tariff for E&G and 15p export.
Elec tracker is 18.74.
Flux is around the 32p are you relying on export to offset the the higher import over the longer term?
import
export
thats fab, What will it go to after October and what tariff are you on?
Oh probs 50p !!!
Flux is around the 32p are you relying on export to offset the the higher import over the longer term
That is the idea. Use battery through the peak period and then hopefully the export will pay for any import when averaged out. Use cheaper period to fill battery in the lean months. I'm not getting paid for export yet which is annoying now we are generating much more than we are using (paperwork apparently).
what tarrif are you getting that export from as id like to move to it 🙂
Average generation in April was 22kWh, average use (for us) was 15kWh. That's 210kWh of additional power. Later Spring and Summer the generation will be better, but still, this is worst case. The difference between import and export on Flux is around 11p/kWh. So, assuming a small battery to avoid the peak, the difference in price from small to large battery is £3500-£4500. Assume you do generate 22kWh average, store 5kWh of that, use 5kWh of that (directly) and export the remaining 12kWh. That's an export generation payment of £80, but you'd then need to import 7-8kwh at other times, so that'd cost you £72. So you're cash positive AND you've saved £3k-£4k on on battery. This makes the ROI on a bigger battery only really making sense in the duller months by charging off peak. In those months you'll maybe need 20kWh, you'd generate maybe 5-6kWh, so you'd need to import 14kWh, doing that off peak saves you £1.60 a day, for 90 days, that's £150 of additional cost a year. That's 23years to pay back the investment on a bigger battery!
Can someone more knowledgeable than me help me out with this one? I'm currently in the process of buying a new house which has a gas boiler and a hot water cylinder. My instinct would be to rip it all out and put a combi in as i hate the thought of using gas to heat a whole cylinder of water just to wash my hands (it has an electric shower). I do like baths though.
So would it be better for me to put a combi in or should i get solar PV on the roof and connect it to the cylinder to keep the water temp topped up? I think the costs of installing either system would be broadly similar (I'm not thinking of batteries at this point).
At the moment, you'll have an indirect cylinder and for PV heating, you'd want direct, or better still, both. I'm not sure if the cylinder can be adapted to take an additional coil. @Trailrat might know?
Regardless, solar PV + Diverter + new cylinder (maybe) will be more expensive and the ROI will be poor. It will be more future proof, but expensive.
We have an oil combi, solar PV and are going to be putting in a hybrid direct/indirect unvented cylinder this year. But the solar + the tank (ignoring batteries) will be £8-10k.
My simplistic notion was that the PV could run the immersion heater somehow (I'm assuming its got one)?
an insulated hot water tank loses very little heat, so whilst you are heating the entire tank you're heating it more slowly (which is more efficient), from an efficiency perspective there's not much in a combi vs tank.
