On-grid domestic battery storage

orrery

thevilla said:

Forgot:  unless your meter is reversing while exporting.   Illegal but don't get a smart meter if you're OK with that.

The electric company may well estimate the additional charge due at some time in the future. You probably have an obligation to inform them.

If you do any reasonable mileage then moving to a time-of-day tariff like economy 7, or one of the newer ones is probably going to benefit you. They go very well with solar PV - you get access to lower rates when you need to charge your car (you want to be out driving it during the day and have it ready fully charged 1st thing in the morning) and the solar generation offsets the higher cost peak units during the day.

I moved to E7 when I was doing about 5K miles per year, and I could switch both my dishwasher and washing machine to overnight using timers - that was almost break-even (a very helpful guy at Ecotricity extracted the data from my SmartMeter and did the calculation). I now do about 10K miles per year, so I'll be quids in.

Pulpdiction

Solarchaser said:

As regards smart meters, I've had ones since 2017, and am still on deemed 50% export fit.
If you are going to charge the ev with a zappi, then I'd suggest you stay on deemed 50%

Do I have a choice?  Is there anything I need to do or just have the smart meter installed and continue to give my FIT readings as normal?

Pulpdiction

thevilla said:

Forgot:  unless your meter is reversing while exporting.   Illegal but don't get a smart meter if you're OK with that.

My meter is 'digital' not a mechanical kind, so not seen it going backwards, guess it can't, it just slows down consumption.

orrery

Pulpdiction said:Do I have a choice?  Is there anything I need to do or just have the smart meter installed and continue to give my FIT readings as normal?

Yes. That's what I do. No problems whatsoever.

Pulpdiction

QrizB said:

Pulpdiction said:

Hi all, had solar since 2015, have a 3.5kw system and it's about paid for itself, so looking at next steps, which is about using some of the power I am exporting.

Given that I am a pretty high energy user, with 2 teenagers in the house, and so far my solar production is very good for about 8 month of the year I want to try and reduce my grid consumption to as near to zero as possible between April and October down from the circa £900 it is costing me per ear for electric at the moment (yes I change my tariffs regularly to try and get the best deal).

Any advice greatly appreciated.

How much are you importing from the grid during those 8 months? Do you have monthly meter readings that will let you work this out?

I've just posted my monthly stats over in the "talking bout my generation" thread. I don't have a battery. During Apr/May/Jun/Jul we imported 154/100/93/99kWh, roughly £23/15/14/15 worth of electricity (total £67). There isn't a lot of scope for a battery to save me money during the productive solar months.

Your numbers could of course be quite different to mine!

Don't know as I have no current way of monitoring, all I can tell you is the kids are both on xboxes all evening and the TV is on plus electric cooker.  The placement of my solar panels means that production slips off after about 6 this time of year.  My panels are split into two strings, I have a Sunny Boy 3600TL inverter so got 5 panels more of less SSE, and then 9 panels more of less east on another roof, so thinking about moving them around and keeping the east facing but when I have a SSE facing extension with a flat roof putting the other string on there and adding another couple of panels to take it up to 4kw.

Sorry another question, do I need to tell anyone about that in terms of FIT providers or can I just do it?  Or maybe add another 3 or 5?

Solarchaser

Pulpdiction said:

Solarchaser said:

As regards smart meters, I've had ones since 2017, and am still on deemed 50% export fit.
If you are going to charge the ev with a zappi, then I'd suggest you stay on deemed 50%

Do I have a choice?  Is there anything I need to do or just have the smart meter installed and continue to give my FIT readings as normal?

Yeah just get the smart meter installed, your fit is independent of that.

Edit, yeah if you add panels on same inverter you need to tell fit... however be aware they will either reduce your fit by a percentage or cancel it altogether... thats what edf told me when I asked.

Hence I went with a stand alone system instead.

If it doesn't go through you fit meter, the fit provider doesn't care.
The dno might, but thats a different matter really

Pulpdiction

orrery said:

thevilla said:

Forgot:  unless your meter is reversing while exporting.   Illegal but don't get a smart meter if you're OK with that.

The electric company may well estimate the additional charge due at some time in the future. You probably have an obligation to inform them.

If you do any reasonable mileage then moving to a time-of-day tariff like economy 7, or one of the newer ones is probably going to benefit you. They go very well with solar PV - you get access to lower rates when you need to charge your car (you want to be out driving it during the day and have it ready fully charged 1st thing in the morning) and the solar generation offsets the higher cost peak units during the day.

I moved to E7 when I was doing about 5K miles per year, and I could switch both my dishwasher and washing machine to overnight using timers - that was almost break-even (a very helpful guy at Ecotricity extracted the data from my SmartMeter and did the calculation). I now do about 10K miles per year, so I'll be quids in.

Only expect to do about 6k miles per year, but got a 10y/o Diesel which is starting to need money spending on it, so cost of change to me is actually cheaper to have an electric company car fully maintained insured, etc, than to get say a £15k loan and buy a 3 year old car to replace my current.  Hence the change.  Fact that it's a Tesla 3 LR AWD is a bonus.

So my thought process was charge the car when not using the solar, and use the over generation at this time of year consider what that means for charging in the winter, likelihood is I am going into the office 1-2 days per week and there is free charging there, so can top up assuming I can get on a charger.  Then got me thinking about battery storage for the home.

 

Hexane

Pulpdiction said:

QrizB said:

Pulpdiction said:

Hi all, had solar since 2015, have a 3.5kw system and it's about paid for itself, so looking at next steps, which is about using some of the power I am exporting.

Given that I am a pretty high energy user, with 2 teenagers in the house, and so far my solar production is very good for about 8 month of the year I want to try and reduce my grid consumption to as near to zero as possible between April and October down from the circa £900 it is costing me per ear for electric at the moment (yes I change my tariffs regularly to try and get the best deal).

Any advice greatly appreciated.

How much are you importing from the grid during those 8 months? Do you have monthly meter readings that will let you work this out?

I've just posted my monthly stats over in the "talking bout my generation" thread. I don't have a battery. During Apr/May/Jun/Jul we imported 154/100/93/99kWh, roughly £23/15/14/15 worth of electricity (total £67). There isn't a lot of scope for a battery to save me money during the productive solar months.

Your numbers could of course be quite different to mine!

Don't know as I have no current way of monitoring, all I can tell you is the kids are both on xboxes all evening and the TV is on plus electric cooker.

Peak power consumption of a modern XBox is less than 200W, compared with peak power consumption of an old-style electric fan oven of around 3000W. The kids would be using more power if they were outside rolling in mud all day and evening, and bringing home multiple sets of dirty clothes that needed washing and drying. (Unless the Xboxes are both connected to huge power-guzzling plasma TVs of course. LED TVs use very little power too.)

In some senses the electric oven (like the dishwasher and the laundry) is more controllable than the kids; if we have the option of making pizza, stir-fry, chilli, a roast or a pie, then we'll make the pie, pizza, or roast in the oven on sunny days, and make chilli or stir-fry on the gas hob on cloudy days. Steak pie for lunch in a heatwave may not be to everyone's taste, of course.

QrizB

orrery said:

Pulpdiction said:Do I have a choice?  Is there anything I need to do or just have the smart meter installed and continue to give my FIT readings as normal?

Yes. That's what I do. No problems whatsoever.

When EDF installed my smart meter they told me to inform my FIT provider (E.ON Next) in case they wanted to move me to metered export. Apparently FIT providers are meant to do that if they can. I informed E.ON and they wrote back promptly to say that they weren't making it compulsory but I could opt in to metered export if I wished. I chose not to, at least for now.

Pulpdiction said:

QrizB said:

How much are you importing from the grid during those 8 months? Do you have monthly meter readings that will let you work this out?

Don't know as I have no current way of monitoring, all I can tell you is the kids are both on xboxes all evening and the TV is on plus electric cooker.  The placement of my solar panels means that production slips off after about 6 this time of year.  My panels are split into two strings, I have a Sunny Boy 3600TL inverter so got 5 panels more of less SSE, and then 9 panels more of less east on another roof, so thinking about moving them around and keeping the east facing but when I have a SSE facing extension with a flat roof putting the other string on there and adding another couple of panels to take it up to 4kw.

Sorry another question, do I need to tell anyone about that in terms of FIT providers or can I just do it?  Or maybe add another 3 or 5?

Yes you can monitor, just read your generation and import meters regularly. Prior to my smart meter install I didn't know how much I was exporting but I could tell that my import in eg. May was 100kWh and my generation was 298kWh, while in June the numbers were 93kWh and 306kWh and July was 99kWh and 319kWh.

Despite generating more than 900kWh over those three months, a battery would have let me self-consume less than 300kWh of it.

As others have said, if you add extra panels to your existing system you will need to tell your FIT provider who will then pro-rata your generation accordingly. Adding a second separate system is simpler; your MCS-accredited installer will take care of the legal niceties.

orrery

QrizB said:

orrery said:

Pulpdiction said:Do I have a choice?  Is there anything I need to do or just have the smart meter installed and continue to give my FIT readings as normal?

Yes. That's what I do. No problems whatsoever.

When EDF installed my smart meter they told me to inform my FIT provider (E.ON Next) in case they wanted to move me to metered export.

It has nothing to do with either EDF or E.ON. It depends entirely what is says in you FIT contract. That is your agreement, and if they want to vary it then they need to get your approval.

People with EVs who started on the Vehicle-to-Grid trials were asked as a condition of the trial to agree to a change in their contract.