On-grid domestic battery storage

QrizB

lisyloo said:

Hi, new to this thread.
whats the rough up front outlay for sonnen for 3.9?
and is it worth 

EDIT: this looks like thousands. How does this stack up?

I'd guess £4500, based entirely on this webpage where the sonnenBatterie eco is stated to come in sizes from 4-10kWh and to start at £4500. Although it seems you can get the Eco 9.43 with 5kWh of battery here for the same sort of money (plus VAT, so £5400).

That seems a bit steep, given that a 7kWh Solis system from here is only £3500 inc VAT.

lisyloo

Solarchaser said:

Do you have a quote you can share?

I mean I'd literally just be googling the cost of the battery, which you can obviously do yourself.

You haven't mentioned which inverter?

I Don’t have a quote yet.
the sonnen batteries look like a few ks so I’m trying to understand how this stacks up if shell say you can save up to £150 per year.
the inverter is solaredge and 7 years old.

can anyone explain how it makes sense to spend £3k (say) on a battery to save max £150 per year and be tied in to a very limited selection of tarrifs.

am I missing something major here?

btw - I have high electricity usage due to a hot tub, so I may not actually export much back to the grid. We’re probably using more of the solar than the average solar user.

QrizB

lisyloo said:

can anyone explain how it makes sense to spend £3k (say) on a battery to save max £150 per year and be tied in to a very limited selection of tarrifs. am I missing something major here?

For some people, it won't make sense. You need to be careful to size your battery to suit your solar panel output and your household usage, and even then it might not be economical.

But I don't understand your "tied to a very limited selection of tariffs" comment. Having a battery (or not) doesn't limit your supplier or your tariff. What it does do is open up opportunities to make better use of time-of-use tariffs (smart tariffs, EV tariffs, even traditional E7 tariffs).

arty688

There are 2 types of saving with a battery 

1. Using excess solar instead of exporting it.

2. Using a time of use tariff so I suppose that limits your choice of tariffs.

I would also say you will use your hot tub mainly at night so without a battery you won't be using solar.

How much (%) of your generated electric do you use now?

lisyloo

QrizB said:

lisyloo said:

can anyone explain how it makes sense to spend £3k (say) on a battery to save max £150 per year and be tied in to a very limited selection of tarrifs. am I missing something major here?

For some people, it won't make sense. You need to be careful to size your battery to suit your solar panel output and your household usage, and even then it might not be economical.

But I don't understand your "tied to a very limited selection of tariffs" comment. Having a battery (or not) doesn't limit your supplier or your tariff. What it does do is open up opportunities to make better use of time-of-use tariffs (smart tariffs, EV tariffs, even traditional E7 tariffs).

There's a shell tarrif (i think) that gives you up to £150 off if you export electricity back to the grid.
If I wanted to take advantage of that discount then I'd be tied into a limited selection of tarriffs that offered the discount.
Of course I could take any tarrif but would lose the discount for exporting back to the grid.

lisyloo

arty688 said:

There are 2 types of saving with a battery 

1. Using excess solar instead of exporting it.

2. Using a time of use tariff so I suppose that limits your choice of tariffs.

I would also say you will use your hot tub mainly at night so without a battery you won't be using solar.

How much (%) of your generated electric do you use now?

The hot tub is heating 24 hours a day on a thermostat but I agree more at night due to colder temps.

How would I work out how much of the generated electric we use?  I don't have usage figures pre-solar 8 years ago unfortunately.
Is there a way to tell? without pre-solar usage for comparison?

QrizB

lisyloo said:

How would I work out how much of the generated electric we use?  I don't have usage figures pre-solar 8 years ago unfortunately.
Is there a way to tell? without pre-solar usage for comparison?

Do you have a smart meter? They mostly measure electricity export, so you can subtract that from your generation reading and see how much you've consumed.

QrizB

lisyloo said:

There's a shell tarrif (i think) that gives you up to £150 off if you export electricity back to the grid.

This one?

https://www.shellenergy.co.uk/smart-home/solar-battery

"Our Solar Storage tariff is currently unavailable. Please check back later for more information."

lisyloo

QrizB said:

lisyloo said:

How would I work out how much of the generated electric we use?  I don't have usage figures pre-solar 8 years ago unfortunately.
Is there a way to tell? without pre-solar usage for comparison?

Do you have a smart meter? They mostly measure electricity export, so you can subtract that from your generation reading and see how much you've consumed.

No we don't.
I did have an appointment to have one fitted but it was cancelled when PFP went out of business.

we generate between 3500 and 4000 (which I assume the solar meter shows kwH).
My bills our annual consumption is 5300.
but I appreciate that doesn't show how much of the generation we use.
So the answer if I'm afraid we don't know what % is used.

QrizB

lisyloo said:

QrizB said:

lisyloo said:

How would I work out how much of the generated electric we use?  I don't have usage figures pre-solar 8 years ago unfortunately.
Is there a way to tell? without pre-solar usage for comparison?

Do you have a smart meter? They mostly measure electricity export, so you can subtract that from your generation reading and see how much you've consumed.

No we don't.
I did have an appointment to have one fitted but it was cancelled when PFP went out of business.

That's a shame.

The next best option is to measure your electricity use daily, and see how cloudy days compare to sunny ones. The problem is that other factors come into it - did you do laundry that day, for example - which complicates matters.