Solar panels Vs battery only

[Andy1733]

I was wondering if anyone has done a cost comparison for battery only, solar only, and solar & battery.

I'm not meaning short term but over a longer period. Eg 5- 10 years.

I can only go from my setup and during the winter I'm leaning towards battery only setup using a cheap rate tariff
And summer it's the solar.
Spring to autumn. It's prob a mix of the 2 though would the spend on solar be better spent on battery's only and having a constant all year

 

[Bob Smith]

Hi @Andy1733

I am not sure I understand what you are trying to achieve.
In Summer, the panels will, like in Winter, not generate enough electricity or not at all when it is raining and of course at night.
Unless you consider that what you sell will compensate what you’ll have to buy, I cannot see why batteries could not be useful in summer too.

Furthermore at the moment there is a 0% VAT on a PV + batteries installation.

Someone has yet to come up on a subscription model where you pay only for what you need depending on the time of the year to avoid having a system sized for Summer which is then undersized for Winter’s needs and the other way round, if you have a system sized for Winter, it will be oversized for the summer’s needs

 

[Andy1733]

Tbh my mouth wouldn't say what my brain posted when I compiled this post.

What I was trying to say was
As an example the few quotes people have posted recently are between 8k (solar only) and 14k (Inc battery's.)

If you didn't buy solar panels and used the money to buy extra battery's and used a cheap rate tariff only to charge them. Would it be just as efficient as just panels, or a mix of panels and battery's. ?

 

[Murdoch]

Interesting idea but not sure of the sense of it.

We have solar but no batteries, and I’m pondering as to weather it makes any sense to upgrade the inverted and add batteries

 

[Andy1733]

For 8k you can get approx 20kwh off the shelf battery's. If you add the inverter and gubbins your around 10k. If you then charge them at the cheap rates available.
1 would you have enough charge be able to fill them each day
2 would 20kwh be enough for the AVG household.
3 is it possible to charge battery's at cheap rate over night then sell access back from the battery's during the day.

 

[binky]

For 8k you can get approx 20kwh off the shelf battery's. If you add the inverter and gubbins your around 10k. If you then charge them at the cheap rates available.
1 would you have enough charge be able to fill them each day
2 would 20kwh be enough for the AVG household.
3 is it possible to charge battery's at cheap rate over night then sell access back from the battery's during the day.

1, you usually get abut 4 hours cheap leccy, so need a charge rate of 5kW or more to fully charge without solar.
2, should be, but every house is different.
4, this can be done with an inverter compatible with Octopus software - it's never interested me so I don't know how well it works. Also worth looking at Sonnen for such things, although I don't knw if they ever did create an energy community for the UK.

 

[Andy1733]

1, you usually get abut 4 hours cheap leccy, so need a charge rate of 5kW or more to fully charge without solar.
2, should be, but every house is different.
4, this can be done with an inverter compatible with Octopus software - it's never interested me so I don't know how well it works. Also worth looking at Sonnen for such things, although I don't knw if they ever did create an energy community for the UK.

I believe itilita do a 5p over night tariff but I'm not sure for how long

 

[binky]

I believe itilita do a 5p over night tariff but I'm not sure for how long

in various posts on here about batteries, 7.5p for 4 hours seems the norm, but clearly that can all change tomorrow as it's all offered by private companies. Shop around is all I can say. I can't see some form of cheap rate off peak disappearing any time soon, it's part of developing a 'smart grid' along with smart meters to reduce peak demands during the day, and given extra demand from EVs, keeping daytime demand down is important to the generators / suppliers.

 

[Bob Smith]

Wouhaaa, a lot of posts today.
Glad you clarified what you meant @Andy1733

Regarding your point 3
As far as I understand the various tariff, you will never be able to buy cheap at night (eg be on Eco 7) and then be able to sell in the day on agile tariff where the export tariff is higher than what you bought at night.

I looked at it too but it would seem that when you are on a tariff it controls what you can do about buying and selling.

What I looked at and be told by Octopus was possible is to be on a tariff let’s say from April til October and on another one for the rest of the year.
In other words, be on a tariff that allow you a good sell price when you have a lot of excess AKA summer, and then be on a different tariff that allows you to buy cheap when you don t generate enough AKA Winter.
Octopus seemed to be happy to be on Eco 7 in winter and Agile in Summer… At least this is what we discussed.

 

[Andy1733]

Thanks Bob. Wouldn't really help with battery only switching between the tariffs.

It just got me thinking when I read on hear about the bloke who charges his car over night. Drives it to work and then runs his office from the car battery before driving he again. Repeat..

 

[Bob Smith]

This is an idea. This has not yet put it into practice. This is @johnb2713 unless you are talking about somebody else.

The same could be said about charging your EV at work (some places it is free) and then run your house from your car in the evening and nights

 

[Andy1733]

This is an idea. This has not yet put it into practice. This is @johnb2713 unless you are talking about somebody else.

The same could be said about charging your EV at work (some places it is free) and then run your house from your car in the evening and nights

I can't remember who it was and the post was a bit sketchy as I was a newby. I may have been dreaming it lol.
I think he had a Nissan leaf and worked approx 2 miles from home.

 

[johnb2713]

I can't remember who it was and the post was a bit sketchy as I was a newby. I may have been dreaming it lol.
I think he had a Nissan leaf and worked approx 2 miles from home.

I'm chewing over buying a Nissan Leaf, 40 kWh battery, charging at home and then my driving to work (we have a retail shop) and using V2P powering the commercial premises. The difference between domestic and business tariffs is enormous and we stand to save a lot of money by doing this. I'm sure there will be something in the regulations to stop this idea so I'm still in the research stage as we speak.

 

[binky]

I'm chewing over buying a Nissan Leaf, 40 kWh battery, charging at home and then my driving to work (we have a retail shop) and using V2P powering the commercial premises. The difference between domestic and business tariffs is enormous and we stand to save a lot of money by doing this. I'm sure there will be something in the regulations to stop this idea so I'm still in the research stage as we speak.

not heard of anything bar the usual DNO restrictions might be applicable.

 

[bladerunnerpv]

I was wondering if anyone has done a cost comparison for battery only, solar only, and solar & battery.

I'm not meaning short term but over a longer period. Eg 5- 10 years.

I can only go from my setup and during the winter I'm leaning towards battery only setup using a cheap rate tariff
And summer it's the solar.
Spring to autumn. It's prob a mix of the 2 though would the spend on solar be better spent on battery's only and having a constant all year

Are you thinking of return on investment primarily?

 

[Andy1733]

Are you thinking of return on investment primarily?

It was just an idea that popped into my head.
I guess ROI would be better going the solar route due to length of warranty and free leccy in the summer.
I guess of your spending 10k on panels and an inverter then you should be able to get 7-8kwh worth of panelsproviding you have the room

 

[johnb2713]

It was just an idea that popped into my head.
I guess ROI would be better going the solar route due to length of warranty and free leccy in the summer.
I guess of your spending 10k on panels and an inverter then you should be able to get 7-8kwh worth of panelsproviding you have the room

If you go solar you get zero VAT on all of the equipment including the battery, theres 20% saving straight away.

 

[Andy1733]

If you go solar you get zero VAT on all of the equipment including the battery, theres 20% saving straight away.

Does it matter if your not vat registered. IE a self install

 

[johnb2713]

Does it matter if your not vat registered. IE a self install

Im not sure on that if you get equipment only zero VAT.

 

[binky]

Does it matter if your not vat registered. IE a self install

you have to be VAT registered to claim back VAT.