Solar panels and battery - any real world reccomendations?

[GinG]

Just gave some cash to the electrician for filling in the form.

The generation team should be able to send you the G99 form if you can't download it from their website, Solar companies make it sound like black magic, but it's not.

Thanks for that. Will see what happens.

Having started putting the costs in to a spreadsheet the costs are somewhat reduced somewhat the more panels you put on as the battery costs are all very similar.

Financially it does make sense putting the biggest array on the roof...we have however decided to not borrow so much on the mortgage and as such our budget is now being squeezed if we want to convert the garage also.

Need to think long and hard about what we want from the setup...looking at my spreadsheet financially it works out cheaper per KWh the more we fit as the battery and inverter costs are fixed.

It may be we use some of the money for the garage conversion and just have to save the money back up to do it later in the year/early next year in order to get the solar panels which in theory would be saving us money in the long run...garage conversion is just a nice to have currently.

 

[GinG]

This was brought up by the guy I spoke to the other day @GinG and he said for SSE where I am anything under 6.5kwh is fine so would be accepted, hopefully it'll be the same for you, but as Journey says the expensive bit is the labour and scaffolding to put up the panels so definitely seems prudent to invest mostly in that now rather than contemplating adding in future.

To be honest not one other mentioned any concern for the DNO, it's only due to the fact the electrician had issues of his own. His house though is built in 1970's and needed a rewire anyway so was nowhere up to modern standards.

One company has said that deal with hundreds per month and very few get charged.

It's a lot of money to invest, I don't want to get it wrong.

 

[GinG]

This was brought up by the guy I spoke to the other day @GinG and he said for SSE where I am anything under 6.5kwh is fine so would be accepted, hopefully it'll be the same for you, but as Journey says the expensive bit is the labour and scaffolding to put up the panels so definitely seems prudent to invest mostly in that now rather than contemplating adding in future.

The only other consideration is go with a big array and reduce the battery from the 8.2 to 5.2.

Saves me around £750-£780 on the install and based on their calculations only reduces my independence by 5%.

 

[GinG]

Surely it'd make sense to just borrow the extra 1k on the mortgage with rates still as low as they are?

It would push us over the 75% LTV and cost more in the long run.

 

[GinG]

Does it though? As in winter when generation is low and you'll be charging the pack from the grid (cheaply) to use later in the day, those extra 3kWh could be 75p per day or more. Plus it means you are able to avoid using the grid during peak time if you use a lot of power, 90% of 5.2kWh is 4.68kWh, so can you see how many kW you will use for the last 8 hours of the day in winter, it it is low then a 5.2 pack may be enough.

EDIT: You really need to examine your daytime/nighttime usage split as well, find out how many kWh you are using and when, in every season.

I can shift the usage whenever really.

For example as I type the house is only pulling 180W.

I can set the dishwasher and washer to run on a timer so even when we are at work they can run at say 11am or whatever the peak time is for daylight.

The issue is on an evening when we use the 2kwh oven but that's fan assisted so I think only pulls around 1kwh ish.

On a morning we have a 10.5kwh shower so we'd be pulling most off the grid anyway for that short time.

Our appliances are quote old, the washer is 11 years old so will be replaced soon with a much more efficient one anyway.

The more I think about it I wonder if an 8.2kwh is overkill and maybe add an additional 5.2kwh in future if prices come down in the battery tech, or if we replace the current EV in a couple of years time with one which allows discharge when connected to the house?

 

[GinG]

Ah right makes sense, think in my head i'd pay more now, although batteries are in short supply so I wouldn't expect you to be paying for it all upfront so gives you a few months to save up at least.

Yeah we were looking at maybe 80% but with everything going through the roof price wise thought we would be sensible.

There is the consideration of 2-3 months of extra saving but then again that then allows us to put money into the garage conversion which would have a massive improvement in our lifestyle.

 

[GinG]

I've now been introduced to Pylon batteries and Sofar Inverters.

The GivEnergy inverters only provide 2.6mwh supply from the battery which may prove an issue on an evening when cooking, making a brew and microwave for example.

The Sofar Inverters provide exactly what they say on the tin and though Pylon batteries are only 90% DOD or even 80% DOD for an extended lifespan the modular system makes adding more storage much easier.

The system will be fitted in our loftspace so it doesn't need to look pretty, I'm wondering if this may be a better system for our requirements.

 

[GinG]

Yes, I mentioned this earlier, if you are drawing or want to draw only from the battery then they aren't great for running many things at once, you can run the back ground house tasks and maybe a fan oven at best. I opted for them due to integration with time of use tariffs and the software on offer, and I very rarely use 2.6kW+ for sustained periods of time at night. I will be looking at adding second pack in the near future, and nearly opted for 2x 5.2kW for this reason.


The Pylon tech batteries are ok, SunSynk also offer a really nice solution with a similar style but offer an 8kW inverter as well, and the packs are 5.12kW (CATL LiFePo4), price seems to be quite competitive.



Looking pretty was not a concern here either, I just went with what I though offered the best solution and the best price. There is a huge amount of research you can do for batteries alone, it can be quite overwhelming, especially when you have different installers telling you different things.

Yeah you absolutely did and I must admit now I've thought about it more I think the GivEnergy is going to be too restrictive and may need to look elsewhere now.

I'll have a look at the Sunsynk. Thanks again mate!

 

[GinG]

Had a quote from UPS Solar and TCL Solar and gave approval to TCL to go ahead. 5.2kw solar array with no battery at this stage. With working from home all day and easily able to move washing and dishwasher to daily load rather than overnight hoping for some savings. Will be adding a battery in future as was advised prices inflated at the moment due to supply so best to wait and get a better deal with more capacity in a year or 2 hopefully.

I'm not sure this is a good idea. As journey says you will miss out on the 5% Vat savings and due to no FIT payments you only get £0.055 per kWh extra generated.

Has the company done you a comparison of solar Vs battery and solar?

 

[GinG]

So I've recalculated my energy usage as I'm back online with my Avro login details and could see some of my previous statements.

I'm now looking at 5000-5500kwh household consumption so I'm now leaving towards the lower scale of panels.

I've had a quote for 10x455W panels, 3.6 GivEnergy inverter and 8.2 batter for £8157.

I'm waiting for a price back on the same panels but Solax battery and inverters.

My thoughts are that any more panels I'm just going to be at a loss...the wife works Mon-Fri so the car would only likely be plugged in on weekend days and would allow me to keep with the 8.2 battery.

The other option is to go down to 5.2 battery as this would bring cost down to £7,390 which would then allow more in the pot for garage conversion.

I downloaded Octo Compare which gives me average baseload as 122W. So this setup would more than do us to help bring our costs down but still rely on the grid.

Issues come at night and morning with showers and oven but again mainly in winter.

Financially I know I'm based going all out initially but one bug bare in the house is the lack of play room for the kids...I'm thinking either will help reduce our costs it's just how much compromise I go for now.

 

[GinG]

What's the best way to work out what is most beneficial?

Over last 12 months I've used around 14.45kwh per day average per day.

Company A is quoting based on the 10 x 455W panels that it will generate 3658kwh.

This works out on average over 12 months at 10kwh per day.

Therefore I am down around 4.45kwh per day?

I can then top this up with a battery...a 5.2kwh will cover this?

Therefore over the year can I assume 5.2kwh X £0.075 (overnight charge) X 7 days x 365days = £141.96 worth of leccy?

I then need to add on a few KWh per day based on what the inverter can pull when we use the shower and cooker to then work out if the 8.2kwh is worth going for? The difference is £767 between the size of battery.

This is average over 12 months...am I missing something here and is it much more complicated??

 

[GinG]

You need to consider that in summer you may produce 40+ kWh in a day and most of that could be exported if not used or stored locally. In winter you may only produce 0.4wh in the whole day.

You can’t really look at as an average over the year as you’ll be getting the most sun when your consumption is the lowest.

Ok thanks for that...

Still absolutely baffled by it all then!! Haha.

 

[GinG]

Sadly it doesn't work like that, through the summer months you'll generate the bulk of the power and won't be able to use/store most of it, through the winter months you're generation will be much lower (I see approx 85kwh per month from 1st November to end of January) with some days only seeing 100-200wh

What sort of system have you got for that sort of generation?

 

[GinG]

Thanks both...

I think I'm understanding it more now.

I'm now leaning in the 4.55kwh panels and 8.2kwh battery @ £8,157.

Even if between Nov-Jan going off maybe average of 85kwh per month generation leaves around 340kwh short.

230kwh can be used from battery an even on latest price of £0.075 would be £17.25 and then 110kwh @ £0.30 would cost around £30 so £37.25 in electric.

5.2 battery would be £69.45 worth of electric.

That's around £100 saving just over them 3 months...

Appreciate its all 'back of a fag packet' calculations but thats quite a bit of savings just over 3 months.

Even if you say over the year it may allow around £200 savings it's just a 3 year payback difference between the 2 battery sizes without any other increases taking place.

 

[GinG]

I've had a quote back but I think they want too much:

3.9 kw system (10 * 390w Trina panels) with no battery - £5.8K (string inverter) or £6.4K (solaredge inverter).
Same as above with string inverter + 8.2kwh Givenergy battery - £9.8K
Same as above with string inverter + 13.2kwh powerwall - £15.6K

That sized solar system vs cost seems overpriced for just 3.9 kws, and the battery quotes don't seem great either.

Still pending a quote back from someone else. May need to seek a 3rd or 4th opinion. I'm definitely wondering if the gov will put forth some incentives in the next year or so to cheapen the installs a bit.



I actually think this might be the best move! 2 batteries in tandem, enough capacity to charge up overnight on a cheaper off-peak tariff, predictable energy costs all year round.

I wonder if this also means you don't have the same levels of paperwork, and the DNO things etc as well, after all it's just some batteries on site

16kwh or so should be enough to basically go the whole day, assuming smart about usage.

Powerwall is interesting as well because it lets you use the Tesla Energy Plan - obviously it's a huge cost, but with the TEP you appear to get the same import and export rates all the time, and it turns your whole house into a giant UPS basically. https://www.tesla.com/en_GB/support/tesla-energy-plan-faqs?redirect=no - huge investment though and still a multi-year payback, especially as you need panels.

Indicative pricing of Tesla plan is very good, you get more for generation, but unit rates are a bit higher than pure off-peak charging.

Seems quite high...

I've been really impressed so far with the contact with GloGreen and Effective Home.

2 multi national companies, Effective Home are coming in lowest so far.

10x455W JA Solar Panels, 8.2 GivEnergy, 3.6 GivEnergy inverter @ £8136...

I am plotting my household usage and I think I can get away with the above and the 1 or 2 times I may make a brew or cook the tea on an evening would mean pennies worth of energy from the grid...not enough to justify bigger systems.

 

[GinG]

So just to update I've just signed the forms for the following:

4kwh Solar
5.2 GivEnergy battery plus 3.6 Inveter.

Got the fella to throw in bird protection and paying £7582.

We bought a new caravan so budget dwindled a bit so this is more inline with the budget than to a higher spec.

Plan will be to add another battery in a few years when things settle down.

I'm happy with the spec and compromise with the budget we had.

 

[GinG]

Nice price, but say you got the washing machine on or cooker and put on kettle you will be well over 3.6 no? Unless I have misunderstood how it all works, one would want no less than 5, ideally even more so you can draw more juice at once from the battery.

But yeah, good price as you say if you can work around it.

If I was looking to go independent from the grid then yes...and even consider 2 X inverters to take the load however in our household it's very rare that we have everything running all at once.

Washing machines will be fine to run with the smaller inverter, same with cooker. The time it takes for the kettle to boil means pence from the grid anyway.

The main thing to look at the inverter is the charge rates so in the winter you can take advantage of the 4/5 HR window to charge battery. Even with the smaller inverter if be able to fill 12kwh battery no bother.

Everyone is different but this is how I've worked my usage out:

Car = always charging from grid overnight.

House base load = average 120w

10x 400w should still allow the house to tick over even in winter.

Washing machine and dishwasher can be put on timers so I can take advantage of sunny days in winter or still run overnight cheaply.

The battery will take the load from 5-6pm to 12.30am and then the house will tick over on cheap leccy until 4.30am, the battery will be charged and not discharging between this window, the battery will take the small load until we wake up around 6am.

If I had unlimited funds I'd love to go all out but you need to to sensible and having this and a battery is far better than just panels or nothing at all.

 

[GinG]

It's only fair if I start updating my thread with what's happening with mine.

So yesterday the lad fitted 10x 400w panels to the roof and will be fitting bird protection.

Today he will be fitting the 3.68kwh GivEnergy Inveter.

Battery is due end of next month and unfortunately the WiFi dongle for the inverter is delayed until end of this month...we are not sure if the system can run 'dumb' until then or if it needs to be fully commissioned before the system will produce.

Photo from yesterday:

 

[GinG]

Any installer recommendations in the North West?

We use around 7000kWh per year and I should really look in to costs for a system that would suit our needs.

DMH Electrical & Renewables

www.dmh-electrical.co.uk

North East based but speaking with him yesterday would travel.

 

[GinG]

Wow been ages since I was last on. Glad to see this is still going strong!

I can’t remember if I updated but I went with a 4kwh system with a 3.6 inverter and 5.2 battery (GivEnergy).

Been very happy and we’ve saved a fortune. I think we would be averaging around £80 a month now over the year including an EV which does around 300 miles per week.

I’d love a bigger battery but with slowing charge speed I can use the octopus intelligent to its full potential.

In the end it cost just under £7.5k just over 2 years ago.