The Solar Thread

I can request a refund via app or online. Only time it won’t let you is when you are near your billing time. If you time it just after a bill I’ve never had an issue

At the risk of winding up the many, many former contributors to this:

Would you do it all over again if you got the choice?

What do I want ?  How much output, how much storage?  (Moderate users, 2-4 occupants.  SE facing garage and SW main roof but with 2 dormers in it to reduce area quite a lot).  Sunnyish southern England.  {adds – gas CH/HW}

No EVs currently (pun deffo intended).

Is there a specific standard/grade of panel/inverter/battery.other gubbins that is far better than others?

What should we avoid?

Ive completed my first year, for those interested:

3.9kw of panels on south roof, south of england

10.4kw battery

myself and my son in the house, gas ch, fan of gadgets and computers

recorded use sep23-sep24

3638 KW which i calculate would have cost me £967.35

I’m on Flux tariff and actual costs over the year -£586.79

total saving £1554.14

This is taking advantage of energy saving sessions, free electricity etc etc, approx 7 year payback based on that calc

6.2KW array, 15 panels, 11 on east facing, and 4 on west facing, ( not ideal, I know ) 10KW battery pack. We are now just over two years in and roughly ( very rough ) half paid for. Yes I’d do it again, in a flash.

Hello All, hoping for a sense check on a recent quote I’ve had, usage in the property is around 3100kwh per year, looking at my smart meter data for the last 6 weeks can’t see any 30min peaks above 2kwh, but this is the warmer months, I’d look further but clicking in my energy providers website is awful and you cant easily export 30min data.

Quote is:

10 x Tiger Neo N-type 430 watt panels

Sunsynk 5kw Hybrid Inverter

Sunsynk 5.32kwh Battery

Claims will generate 3,900ish kwh per year which exceeds the current usage but that generation obviously wont perfectly match the demand I expect, happy to hear any feedback on this quote!

The numbers seem right in terms of generation.

Battery is very low capacity for any load shifting so hope your in all day to allow you to make use of the power.

Flux rates  have been tightened and no longer makes sense to use flux instead of battery

Flux rates have been tightened and no longer makes sense to use flux instead of battery

Did you mean grid instead of battery? If so I’d agree – ideally you need enough battery to get you through a murky winter day without drawing from the grid away from the cheap overnight period, whatever that is from your energy provider of choice

Estimated generation is easy to check by sticking your details into PVGis and see if you get the same ballpark. 

https://re.jrc.ec.europa.eu/pvg_tools/en/

Is that the max number of panels you can fit? If not I’d look at maxing that out as the incremental cost per panel is small for a given array.

Is anyone on here using a Huawei system? If so, did the latest app update and inverter/battery updates throw your set up into a spin?

Would you do it all over again if you got the choice?

Absolutely. NW England here with 10 S facing panels and 10 W facing 7.47 kWp with two Solar Edge inverters (two inverters because we added 6 west facing panels when we rebuilt the garage) and Tesla PW2. 6.64 MWh output last year which is about just over half of our requirements (we charge two EVs). My advice would be to install as many panels as you can (panels are cheap scaffold is not) and get home battery storage. In fact even if you can’t fit panels to your roof get home battery storage and a time based tarrif like Intelligent Octopus Go especially if you have an EV. I reckon the Tesla PW2 will have paid for itself in 3-4 years not taking into account that it maximises our use of solar.

Anyone got any experience of Fox Ess PV and battery systems?

Thank you for the replies trail rat and the purist:

Battery is very low capacity for any load shifting so hope your in all day to allow you to make use of the power.

I do WFH and understand need to move some household items like washing machine and dishwasher to midday to capitalise on energy generated

Is that the max number of panels you can fit? If not I’d look at maxing that out as the incremental cost per panel is small for a given array.

No, I shopped the quote from one firm with another and they came back with an almost like for like and another with 16panels, 2 batteries a bigger inverter, but for now its out of budget.

I think I am right in saying that if I did go 10 panels, inverter and battery, I can always add to this?

One other question, when I shopped the quote the other firm came back cheaper with the same brands used for panels and battery, but they had quoted on a smaller 3.6kw inverter. They claimed on the phone this should be fine with the 4.5kw system, some googling suggests this is down to needing approval for 5kw from the DNO and not for 3.6kw. Will this smaller inverter have any real world impact to my ability to export energy? I assume no impact to battery charging.

Will this smaller inverter have any real world impact to my ability to export energy? I assume no impact to battery charging.

Our inverter is that size, note that you can easily exceed its capacity and then you’re topping up from the grid. A couple of hobs and the oven, for example.

What he said.

Also bigger than 3.6 inverters tend to have actual fans rather than pasive heat sinks.

There can be an issue with noise pending your site.

Do not let them put batteries outside. Batteries no matter what they tell you do not like being below 10 degrees and their charge and discharge rates slow down to a stop below about 6.  Ideally you want the battery and inverter in the same insulated and adjustably vented area.

You want to keep the heat in the winter for the batteries and you want to get rid of the heat in the summer.

(Unless of course you have onboard heating)Cooling ala power wall but then your power efficiencies go into that )

Trail Rat – that’s not true of all batteries.  Our LG RESU 12 pair  functioned perfectly down to minus 13.  They’re bolted to the outside of the house.  They’re now in an Un-insulated enclosure along with the inverter.  Fine in both hot and cold weather.

Also, whilst our inverter is rated to max 6kW (7kW actually) the fans don’t kick on until the load exceeds 70A.  Everything below that is silent.

Most LG packs are rated for normal function at temp ranges from -10 – +50, so ours may not have used the normal full power at5kW, but it was close.

That’s true. If your using NMC tech you want it outside. Preferably as far from your house as possible.

If they are proposing to fit NMC  battery’s in this day and age. Ask them to reconsider.

NMC is fine so long as the battery thermal circuit is designed for the environment it’s in.  NMCs are used in everything from Tesla M3s all the way to house batteries and phones.

Tesla M3 moved to life4po a while back.  – 2021 siting safety as a key driver.

To anyone looking at fitting batteries …. I suggest looking up the differences before you sign up.

I wouldn’t be having NMC near my house .

https://www.gov.uk/product-safety-alerts-reports-recalls/product-recall-resu-ess-home-batteries-lg-ess-battery-division-2103-0025

Not all M3s.  the LR and Performance kept the NMCs and it varies to this day.  As ever with Tesla, safety will be A factor but price will be the main driver.

One bad batch of cells (from 7years ago) doesn’t make a substantial case.  My cells were produced in 2022 and are obviously fine.  2 years further on and they’re still at 99% state of health (same as when they were new) despite being charged and discharged every day.

Whilst the electrolytes in LiFePo batteries are not flammable, they can still catch fire and have done in several M3 standard ranges.  The fire is less energetic in the initial phase, but once it gets going, it’s still going.

Most manufacturers list a slightly higher risk in NMC and slightly higher degradation if used to capacity.

Thank you Ransos and Trail Rat, I’ll keep it spec’d to the 5kw inverter.

I assume the battery will end up being fitted in my loft, manufacturer spec gives operating range -20c to 60c so should be okay, my loft does get hot, but not 60c!

Time to haggle on the price before getting an install date.

Battery in the loft isn’t allowed in new install because MCS cartel.

They didn’t receive guidance in time so went to NMC guidelines. Basically they don’t want them anywhere near your house.

Mines in the attic because it predates the guidance and I was much happier to have life4po up there. -it was between there and the garage. The attic had much less thermal swing

I have a quote for a Tesla power wall and the installer wouldn’t put that against the house even.

end up being fitted in my loft

Without googling I think there is a recent BSI recommendation not to fit batteries in lofts. There may be instances where its fine and IIRC it was a response to (a very small number) of home battery fires. Just may be worth looking into before you commit. From a couple of experts I have spoken to they claimed that after feedback these things can become law in future.

https://givenergy.co.uk/industry-update-home-battery-installations-in-lofts/

Mine are in my garage and I just wrap them in a cheap cylinder blanket when the weather starts to cool, tends to keep them around high 20’s normally with spikes when charging from the grid or solar.

Battery in the loft isn’t allowed in new install because MCS cartel.

It is allowed with certain battery types and in certain circumstances although as I said above, this may change in future.

It is allowed with certain battery types and in certain circumstances 

Has it been revised ? Initial guidance was blanket ban on doing so .

The bs referred to by the MCs states

The following locations are strictly prohibited:

Unsuitable locations:
Rooms in which persons are intended to sleep.

Routes used as a means of escape that are not defined as protected escape routes, including landings, staircases and corridors.

Corridors, shafts, stairs or lobbies of protected escape routes.

Firefighting lobbies, shafts or staircases.

Storage cupboards, enclosures or spaces opening into rooms in which persons are intended to sleep.

Outdoors (ground-mounted or wall-mounted in a suitable enclosure) within 1 m of:

escape routes;

doors;

windows; or

ventilation ports.

Voids, roof spaces or lofts.

Within 2 m of stored flammable materials and fuel storage tanks or cylinders.

Cellars or basements that have no access to the outside of the building.

If it was me I wouldnt install in a loft, although not everbody has the luxury of a garage or “external” space.

I think also if its not prohibited now, it may become so in future and moving them then would be a bugger if it became retrospective.

I will ask where they are thinking of putting the battery then! After asking for the inverter to be increased to the 5kw version, I got the add ons offered to me of Bird Protection and Optimisers, My street has no issue with birds so think I’ll be fine, Optimisers could increase output from 3850 to 3900 they said which seems tiny for the cost outlay!

I will ask where they are thinking of putting the battery then!

Might be worth having a think about where you want it to be rather than letting them talk you into putting it where it’s easiest for them to fit it. Bird protection is probably worth it if you have the likes of pigeons or starlings in the area but I’ve seen one install where they’d used shiny aluminium rather than the usual black mesh and it looked horrendous – I’d rather have had the birds. Optimisers might be useful if you’re going to have any shading affect the array – but then only on certain circumstances. If shading could completely block at least one panel in a string while the others are unshaded (eg shade from a chimney stack or tree) then it’s worth thinking about as the one shaded panel affects the whole string. If the shading encoraches on all the panels in the string uniformly then they’ll have less effect.

it’s worth thinking about as the one shaded panel affects the whole string

That’s hasn’t been the case with modern panels with bypass diodes for quite some time… Like 10s of years my parents 2008 install has them –  Hence I have never seen the draw for optimisers other than extra cost for installer and extra data for the user.

First post on forum in years, but the ST hive mind has always been a go-to for knowledge.

Looking at options for me, have read from start to end, but nothing really fits my needs.

Live in Shropshire in a single story converted barn in a conservation area, which may limit one roof  aspect.   But have total of 7 small’ish  roofs (6m x 3m)  two of which have small velux’s in .   There’s are three W facing and three E and one S facing (though unlikely to be able to use that one).  Basically three apex’s parallel to each other, and one at 90⁰.  All in the open, though the adjacent roofs give a bit of shade to the next early hours in winter.

We currently heat and hot water via LPG, (no mains gas ). boiler coming towards the expected end of life replacement, hot water is tank and it does have a separate electric connection though its never been used,  and a freestanding log burner for heat only.   Heating is via wet underfloor only which to use effectively has been really expensive, so tend to rely on wrapping  up and the log burner.   Only two of us, and both work similar days, and use about 3800KwH leccy a year.  All the heating and electrics are coming up to 20 years since conversion.

We need two cars, and are open to electric for these on replacement, and commutes are about 30 miles return in opposite direction, not really heavy car users, so fuel bill combined is about £200 month.

Will hopefully live long enough to see a ROI, and only see bills being tighter as things go on currently, so just planning ahead while I have some spare income.

Open to all suggestions, and problems anyone sees,  as nice to see that most would do it all over again.   And any recommended installers this way.    In no real rush, and waiting to see what the budget takes away too.

Thanks.  Mark

so, my install was done in august 2023

I noticed a roof leak in the winter of that year, relatively light, i keep a cat litter tray under it in the loft and check/empty every few months, noticed it due to some staining on my bedroom ceiling.

I can see in the lower  part of the pitch of the roof, the felt has been disturbed and is hanging down/ strip missing.. don’t ask me how, i just know it wasn’t leaking and i hadn’t noticed it missing before. And i also understand a proper repair involves pulling up a lot of roof to replace from the bottom up essentially…… i haven’t attempted a bodge yet

My installer was at the end of the country, so i wanted to get a 3rd party assessment before getting on the installer’s case. The 3rd party is mate of mine, and unreliable, and still hasn’t visited. Subsequently, in my year window of install, it seems the installer no longer exists (dual fuel solutions ltd)

I do have the HIES? insurance stuff? not sure if that just covers hardware or what, obviously house insurance etc

essentially, what would be the best way forwards do you think?

Mine are in my garage and I just wrap them in a cheap cylinder blanket when the weather starts to cool, tends to keep them around high 20’s normally with spikes when charging from the grid or solar.

Is this common practice? This will be our first winter since getting a solar system so I’m interested to hear what people do.

Am I missing something in this calculation …  ???

If you have a 10kWh battery and charge it for 7p/kWh during the night, then if your daytine tariff is (conveniently) 27p/kWh you are saving 20p/kWh, or a total of £2 per day, or £730 per year. If your battery cost £7300 (other assumptions available) it’ll take you 10 years to break even. Is there some other factor that I’m ignoring ?

Is there some other factor that I’m ignoring ?

Solar generation.

Solar generation.

How does that factor in ?

I do have the HIES? insurance stuff? not sure if that just covers hardware or what, obviously house insurance etc

essentially, what would be the best way forwards do you think

Not sure at all, but two things pop to mind:
1) Were the installers registered with HIES?  If not then obvs no cover there.

2) You’re already over 12 months since the install and as you didn’t report the leak earlier they could easily argue that it’s outside the insurance window.

….. You may just have to get a roofer in and get it fixed yourself.

yup, HIES registered

and yes i know ideally within the first year it would’ve been good to raise the issue :S

Re, DRJ

solar generation, instead of 7p a unit, its free, plus your export income, on flux,for example, peak export is much higher than the cheap import

How does that factor in ?

I generated 4753kwh last year, roughly £950 on tracker rate I didn’t have to buy in.

I noticed a roof leak

AAMOI how did they install the panels – by drilling through roof tiles and relying on rubber seals around the fixing? Or by taking up tiles and installing the fixing without damage (if you see what I mean) ?

solar generation, instead of 7p a unit, its free, plus your export income, on flux,for example, peak export is much higher than the cheap import

Yes, I get that. I’m not (for once) being argumentative :-). I’d just like to see a detailed modelling of how a battery functions in a domestic system, taking into account the times it gets charged and the times it gets discharged. For me it’s a bit academic at the moment cos we have a legacy FIT which is ludicrously generous, and which I don’t want to compromise by changing my installation. But I’m curious to keep my finger on the pulse to see what might be possible in the future.

Is this common practice? This will be our first winter since getting a solar system so I’m interested to hear what people do.

Not sure. I may be a bit OTT but I have installed Home Assistant and in the depths of winter I noticed the battery temps were dropping quite low in between force charges from the panels or the grid so I just went for this cheap option to keep the temp a bit more consistent, which cant hurt. I dipped into a couple of FB forums and others had build insulation boxes around them etc. Suppose it depends how cold they get in the depths of winter. Ours our in the garage.