Difference in Solar PV and Battery quotes

Solarchaser

Screwdriva said:

zxzxzx said:

Just to play devils advocate, and not disagreeing with what either @QrizB or @Screwdriva say regarding payback on batteries. 

If you want to put time and work into the process you can improve on income.

“At current tariffs, with export at 15p/kWh and import at 25p/kWh, a battery will save you 10p/kWh for each kWh of solar that you store in it to use later”

Across 2024 my import was about 10p/kWh  with 15p export which will shorten payback.

 On which subject, payback is not overly important to me, I wanted to reduce my paid for electricity and do a bit for the planet and my grandchildren and I had the money to spend.

Different folks, different strokes.

I'll let @QrizB come back to you on his numbers but what I will say on the doing your bit for the planet bit is that perhaps scarce resources like Lithium Ion batteries are better offsetting more carbon in EVs than they do serving as a UK grid powered home's battery, especially in the crazy geopolitical world we find ourselves in. 

I do agree that they have a place in high consumption households or to provide relief from frequent power outages. Beyond that, batteries appears more of a sentiment driven indulgence. 

akh43 said:

DMEGC Magnetics 3.600 kW, which I saw on another thread classed as bargain basement panels, not sure if they are better or not that the Aiko from the other quotes.

DMEG and Aiko are both low end, cheap Chinese owned brands with relatively low track records. Generally speaking, Chinese panels brands have among the worst ethical track records in modern history. 

akh43 said:

I think I would like a battery so I could utilise when no solar being generated, but not sure which size would be best.

See above comments on battery. If you want it despite never paying you back the £ you spend on it, hey, it's your home and your money so your decision! 

Sorry, but thats pretty flawed.
Who says home batteries are a worse use of lithium than EV's???
A battery that's cycled every day is better use of it than an ev sat on someone's drive, and since modern batteries are pretty close to 100% recyclable, it's not so much a use of precious resources. 

Nobody is crying out about cobalt mines when its used for refining crude oil, as it has been for decades.

I'm not sure sentiment driven indulgence is fair to be honest, it seems very dismissive.

I got batteries in 2018 as a project to see if I could reduce my grid usage, it worked, then I got more and it got better, then I got more and it got better again, and more recently I use them to stop me buying peak electricity... so using when the grid is dirtiest, and also for exporting when the grid is dirtiest, so that my neighbours arnt contributing as much to the demand on the grid when it's dirtiest.

I've already made the case several times that they can pay for themselves in a few years by importing off peak and exporting peak, so you know it's true.

It's fine that you believe in solar and not batteries, that's all good, different strokes for different folks as I just said in another thread and realised now I picked it up from zxzxzx, but its not fine for you to say it will never pay back, when you have been given several examples where it will, and is.

My own batteries discharged over 8000kwh last year which saved me between £1200 and £2000 (depending if they were discharging to cover house use at 27p/kwh or were for export at 15p).
I bought them for under £8k and they are available for ~£6k now, so that's a 4-6 year payback.
That's pretty much inarguable, so please stop making such definite and dismissive statements about batteries, when you know it's not accurate.

Screwdriva

Solarchaser said:

I've already made the case several times that they can pay for themselves in a few years by importing off peak and exporting peak, so you know it's true.

It's fine that you believe in solar and not batteries, that's all good, different strokes for different folks as I just said in another thread and realised now I picked it up from zxzxzx, but its not fine for you to say it will never pay back, when you have been given several examples where it will, and is.

My own batteries discharged over 8000kwh last year which saved me between £1200 and £2000 (depending if they were discharging to cover house use at 27p/kwh or were for export at 15p).
I bought them for under £8k and they are available for ~£6k now, so that's a 4-6 year payback.
That's pretty much inarguable, so please stop making such definite and dismissive statements about batteries, when you know it's not accurate.

Sorry to share, the Fogstar/ Seplos batteries you own are not what the overwhelming majority of end users consider for home storage. I know I am definitely not thinking of that type of battery when sharing my thoughts. For those who are open to a DIY type battery, the economics are definitely favourable as they are cheaper to purchase - no arguments from me there. 

And no, I have never said I don't believe in battery storage. I have helped dozens with PV + battery solutions when the consumption/ need justifies it.  When the use case does not support the upfront cost of the purchase, then I'm sorry to share, neither will I. 

Solarchaser said:

Sorry, but thats pretty flawed.
Who says home batteries are a worse use of lithium than EV's???
A battery that's cycled every day is better use of it than an ev sat on someone's drive, and since modern batteries are pretty close to 100% recyclable, it's not so much a use of precious resources. 

Nobody is crying out about cobalt mines when its used for refining crude oil, as it has been for decades.

Do you really believe that: 

1) Offsetting the burning of 100% fossil fuels (diesel/ petrol) in a vehicle is inferior to offsetting the burning of <50% natural gas as part of the UK household electricity mix in a PV household?
2) People purchase EVs to keep them sat on their drives vs. actually drive them 8K miles per year on average?
3) Lithium ion batteries are abundant, made from readily available raw materials?
4) Cost is not a major barrier to EV adoption?

Those are questions to reflect on. I'm keen not to hijack OP's thread any further. Feel free to start a new one and we can dive into this topic elsewhere.  

Solarchaser

That's pretty funny tbh.
You make a broad, flawed definite statement which I reply to, you make another broad statement and suggest starting another thread to reply to it.
Hmm.
I'd suggest instead, stop making statements which don't stand up to scrutiny, and no-one will need to reply to them.

Not everyone has fogstar,  yep, same as not everyone has powerwalls, and at no point did I suggest that was the case, nor did I suggest only if you pick the same batteries as I have, will the economics make sense.
They made sense with the pylontech I had before seplos too, and even you would struggle to call them DIY.

Average mileage is a strange thing to quote, as averages mean nothing in specific cases.
My wife does 1-2 charges a week of her 20kwh car battery, and my batteries discharge over 30kwh every evening.

As for your 4 points, none of them is what I said, regardless of your strawman suggestion otherwise, sorry that you think that from what I wrote.

zxzxzx

@akh43
You should be able to see that there are a variety of opinions above! No one is 100% right because no one is you in your situation.

 I would suggest you ask yourself what your personal outcome is. Why are you installing solar panels? What are you looking to achieve? Do you want to ‘work’ to make battery use effective? How much effort do you want to put in going forward, as panels are fire & forget.

You did raise the point in your second post about charging batteries on the Octopus Forum, this is what I do, over the winter there are times when I have been paid 4/5p pk.wh to fill my batteries! Batteries are not just about storing sunshine for use at night. Depends, as I said, how much time you want to invest in achieving your objectives.

Good luck.

PS I am a very happy Givenegy battery/inverter user in my second year of ownership.

Magnitio

I agree with a lot of the arguments on both sides above. My concern is that a lot of solar installers are currently pushing the installation of batteries because that is where they make a lot of their profit. Most people who have them installed won't be importing/exporting to maximise their income. It will help significantly during Winter if using low overnight tariffs, but for low users during the Summer may not be a great deal of use.

I have a battery and am very happy with it. However, if I had gone ahead with an installation without the battery, the payback on my system would have been shorter.

Screwdriva

Solarchaser said:

That's pretty funny tbh.
You make a broad, flawed definite statement which I reply to, you make another broad statement and suggest starting another thread to reply to it.
Hmm.
I'd suggest instead, stop making statements which don't stand up to scrutiny, and no-one will need to reply to them.

Not everyone has fogstar,  yep, same as not everyone has powerwalls, and at no point did I suggest that was the case, nor did I suggest only if you pick the same batteries as I have, will the economics make sense.
They made sense with the pylontech I had before seplos too, and even you would struggle to call them DIY.

Average mileage is a strange thing to quote, as averages mean nothing in specific cases.
My wife does 1-2 charges a week of her 20kwh car battery, and my batteries discharge over 30kwh every evening.

As for your 4 points, none of them is what I said, regardless of your strawman suggestion otherwise, sorry that you think that from what I wrote.

So far, the only "scrutiny" you've offered is your own personal experience without supplying evidence to actually prove what you have shared is accurate. When I shared national average driving distance as a proxy, you raise your wife's example while ignoring the inputs of <50% natural gas being burnt via the grid vs 100% crude oil via the tailpipe? When @QrizB shared a simple calculation relevant to OP's use case, you ignored that too. 

To correct you, I did not say "not everyone has Fogstar", I said the vast majority do not consider DIY batteries like Fogstar. It's not on most PV customer's radars when considering a battery.

However, nearly every single recent battery installation I have helped with has either expressed interest or installed the PW3. I'm only a tiny sample size of a few dozen but in my experience, those who can't/ won't spend the £ go for cheaper brands, from GivEnergy all the way down to Pylontech, which I helped several households with (at their insistence) in 2022/23. Must be said that Pylontech appears to have disappeared overnight - no one requests it anymore from any of the installers I speak to - I will try to understand why when I speak to a few installers next week. 

I'll say it again, batteries have their place if the number's justify it- that means lower cost & higher consumption. I'm not convinced that Fogstar batteries are the solution, based on my understanding of the end consumer's mindset. Sorry, but I won't stop sharing both these viewpoints, even if it ruffles feathers ( which is not my intention).  

Magnitio said:

My concern is that a lot of solar installers are currently pushing the installation of batteries because that is where they make a lot of their profit. Most people who have them installed won't be importing/exporting to maximise their income. It will help significantly during Winter if using low overnight tariffs, but for low users during the Summer may not be a great deal of use.

Spot on! I see this all the time. 

Solarchaser

You missed the point entirely I'm afraid.

I can give specific examples because of what I have done or people I have helped, some with solar only, some with batteries.

At no point have I said everyone should get batteries, and I no point did I state every battery offsets more than every EV, because I don't make sweeping general statements as if they are fact, you have been, and you shouldn't because its not fact, it's only your opinion.

Stop making flawed statements and people won't need to respond to correct them. Simples.

Screwdriva

One of us definitely has missed something, of that I am sure. Rest assured, I will continue to share what I know to be accurate for the benefit of others and look forward to engaging constructively with anyone who has anything contrary to share.