Solar Battery Plans - enough?

pete-20-11

Bimbly said:

pete-20-11 said:

You can have FIT generation payments and opt out of the FIT export payment (getting SEG instead). 

Yes, that's what I thought.

Anyway, none of this is addressing the issue of if my logic of getting 6kWh battery makes sense. Or should I look at bigger.

Is say aim for a battery that roughly matches your daily consumption. Don't go too big otherwise you won't break even (unless your motivation is not money related). 

ecraig

Newbie_John said:

2640 kWh at 25p rate is £660.
As you already have freeish energy during the day, your solar won't always charge it so you'll need to top it up at night at cheaper rates, energy loss.. your savings will be like £400 max a year? 
If you put £4500 to a savings account at 5% it will generate £225 interest from year 1, unlike battery from year 10+?

But 2640 kWh imported at a cheap overnight rate at, let’s say, 10p per kWh is a £264, and with interest rates likely to fall it seems this might be a sweet spot to import from the grid and store in a battery instead. 

Newbie_John

ecraig said:

Newbie_John said:

2640 kWh at 25p rate is £660.
As you already have freeish energy during the day, your solar won't always charge it so you'll need to top it up at night at cheaper rates, energy loss.. your savings will be like £400 max a year? 
If you put £4500 to a savings account at 5% it will generate £225 interest from year 1, unlike battery from year 10+?

But 2640 kWh imported at a cheap overnight rate at, let’s say, 10p per kWh is a £264, and with interest rates likely to fall it seems this might be a sweet spot to import from the grid and store in a battery instead. 

Sure, but the energy prices are dropping too.. so the saved amount will be lower in the future.
For example you can get 5 year fixed at 4.6% now, so with £4500 after 5 years you will have £5535.
With solar battery purchased for £4500 generating £400 a year you will have.. -£2500. If things don't change in 10 years time you will have £6600 Vs £0.. and at some point in 20 years you would need to get rid of the battery - which also will likely cost money.

Coastalwatch

Bimbly said:

I have 3.24KWp solar system consisting of 12 x 270w PV panels. When they were installed in 2017, a battery wasn't recommended. I'm now planning to get a battery installed. I've gone for 6kwh because, at £4.5k installed, it'll be paid for by a recent windfall. And it was recommended by the installers. Now I'm thinking - is the battery big enough?

My logic is, during the winter, I can charge it up on cheap tariff overnight. Then, if needed, I can top up mid-afternoon to avoid drawing from the grid at peak (Octopus Agile tariff). So even if an overnight battery charge won't last all day, I'll be saving money on the bill.

Last year, I used 2,640kWh from the grid. In the darker winter months, it averaged 7-9kWh per day. But usage next year is unknown as I'm due to get a hot tub to help my aching back (only a smaller 3-seater, but decent well-insulated model).

My logic is, it's probably only three months of the year in winter when electric use is that much higher. And, as I say, I can charge up the battery twice in 24hrs over that period. Also, if I get this installed and decide to add to the battery capacity, I can. The installers said the cost of the initial install is a lot higher because of the infrastructure, so adding more battery is not so expensive.

That seems logical - right?

If you are planning a hot tub then I'm not sure there's a domestic battery available to cope with that. When I looked into what a hot tub consumed energy wise it turned out I could run my EV for a week with the energy a hot tub required per day!

Any thought of ever owning one soon evapourated.

Reed_Richards

You might be able to get a hot tub with a dedicated heat pump that would cut the running costs, which I understand are normally painfully high.

Bimbly

Screwdriva said:

Which battery are you considering? 

Solax, as it has a heating element in it for outside.

Bimbly

Newbie_John said:

2640 kWh at 25p rate is £660.
As you already have freeish energy during the day, your solar won't always charge it so you'll need to top it up at night at cheaper rates, energy loss.. your savings will be like £400 max a year? 
If you put £4500 to a savings account at 5% it will generate £225 interest from year 1, unlike battery from year 10+?

Yes, I did all the maths.

Bimbly

Reed_Richards said:

You might be able to get a hot tub with a dedicated heat pump that would cut the running costs, which I understand are normally painfully high.

The people who have really high bills from hot tubs are ones who buy cheap without insulation or get an inflatable one. It's true they take a lot of energy though. However, if I could wake up with fewer headaches, it'll be worth it.

Heat pumps are generally not worth it. Spend £2,500 on a heat pump (cheap ones don't function in winter, really), it saves you £500 a year and then dies after five years (which they do) and you have saved nothing. Which is why I thought it would be better to spend the money on a system which will benefit the whole house, like a battery.

I've been gifted £5k and decided to spend it on something tangible rather than it bit frittered away with this and that.

Bimbly

As no one really wants to actually answer my question, just tell me stuff I already know, I'm going to stop watching this thread.

Screwdriva

Bimbly said:

Heat pumps are generally not worth it. Spend £2,500 on a heat pump (cheap ones don't function in winter, really), it saves you £500 a year and then dies after five years (which they do) and you have saved nothing. 

Bimbly said:

As no one really wants to actually answer my question, just tell me stuff I already know, I'm going to stop watching this thread.

Such a shame to lose so much humility on these subforums. You'll be sorely missed!