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Increasing an array over 4kW with batteries?


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Im looking for some advice as I haven’t been able to get any answers from solar installers, probably due to them being run off their feet!

Im buying a property that has about 3.2 kW of solar panels installed in around 2011. Im a bit vague because the homeowner has no details of the array, so Ive had to do some detective work to find this detail out (14 panels in SW direction on highest FIT tariff)

The panels aren’t performing as well as I would have wished producing about 2368 kW per year, but it’s a useful FIT income of £1500 p.a.

I would really want to increase the number of panels and could do so massively with a ground array as there is plenty of space around the property, Im conscious that this could be a problem and would require DNO permission if I go over 4kW. However it hardly seems worth doing unless I do go over 4kW.

My question is, is there another way to go? Could for instance I have a separate array, not grid tied, that purely charges batteries, while the original array also charges the same batteries when it has excess production? Obviously I don’t want to lose the FIT payment, but I would like to up my production figures substantially.

Any help would be greatly appreciated. Thanks

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8 minutes ago, bontwoody said:

Im looking for some advice as I haven’t been able to get any answers from solar installers, probably due to them being run off their feet!

Im buying a property that has about 3.2 kW of solar panels installed in around 2011. Im a bit vague because the homeowner has no details of the array, so Ive had to do some detective work to find this detail out (14 panels in SW direction on highest FIT tariff)

The panels aren’t performing as well as I would have wished producing about 2368 kW per year, but it’s a useful FIT income of £1500 p.a.

I would really want to increase the number of panels and could do so massively with a ground array as there is plenty of space around the property, Im conscious that this could be a problem and would require DNO permission if I go over 4kW. However it hardly seems worth doing unless I do go over 4kW.

My question is, is there another way to go? Could for instance I have a separate array, not grid tied, that purely charges batteries, while the original array also charges the same batteries when it has excess production? Obviously I don’t want to lose the FIT payment, but I would like to up my production figures substantially.

Any help would be greatly appreciated. Thanks

Yes you could have an off-grid portion and take for example all your lighting and other light loads off the main board and be semi-off-grid which is something I am looking at doing. I am going to start small by taking the garage and outside lighting off-grid, my plan is to install a 6 way consumer unit next to the main consumer unit and start moving circuits as and when capacity permits, I will always allow for another means of AC input (generator or grid) via the charger/inverter so on a grey winters week, I can still pull those circuits onto the grid. 

 

I also contemplated making my loft conversion an off-grid space. 

 

My plan long term is to come off grid 100% but I want to go through a period of discovery and learning first. 

 

 

 

 

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Unless you build a system that is entirely off grid you can't avoid DNO approval. The DNO are interested in the export capability, not in what it actually exports. So if you add more panels on a separate inverter and/or a battery they need to know.

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1 minute ago, SteamyTea said:

You need planning permission to go over 9m² on a ground array.

Do the existing modules need a good clean?

 

If no one can see them I wouldn't bother. I have put them on my garage and your meant to have PP for that but no one can really see my roof. 

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3 minutes ago, SteamyTea said:

You need planning permission to go over 9m² on a ground array.

Do the existing modules need a good clean?

 

Quite likely and it will be one of my first jobs 🙂

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Just now, Carrerahill said:

Not true. 

How would you avoid DNO approval? I thought as soon as you connect any generation to the grid they need to know about it.

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8 minutes ago, Carrerahill said:

Yes you could have an off-grid portion and take for example all your lighting and other light loads off the main board and be semi-off-grid which is something I am looking at doing. I am going to start small by taking the garage and outside lighting off-grid, my plan is to install a 6 way consumer unit next to the main consumer unit and start moving circuits as and when capacity permits, I will always allow for another means of AC input (generator or grid) via the charger/inverter so on a grey winters week, I can still pull those circuits onto the grid. 

OK, so I would need to have a seperate consumer unit and decide which circuits were battery driven and which grid driven. How exactly would you put them back on the grid if the batteries were dry?

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18 minutes ago, bontwoody said:

Obviously I don’t want to lose the FIT payment, but I would like to up my production figures substantially.

Same boat as us but you have a more lucrative FIT deal with another 14 years to run so not worth loosing . First off speak to your DNO to see what the chance of upping export is. We had an in principle agreement to double export in a couple of days with formal approval being processed now.

Once you know if you can increase export you can plan your next move. 

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17 minutes ago, bontwoody said:

 How exactly would you put them back on the grid if the batteries were dry?

If youve gone off grid to avoid DNO approval then you may still need DNO approval for the changeover mechanism to ensure that the off grid PV and batteries dont become on grid when you reconnect to the grid that you dont want to connect to🤔

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7 minutes ago, Dillsue said:

Same boat as us but you have a more lucrative FIT deal with another 14 years to run so not worth loosing . First off speak to your DNO to see what the chance of upping export is. We had an in principle agreement to double export in a couple of days with formal approval being processed now.

Once you know if you can increase export you can plan your next move. 

That sounds sensible, im just eager to get my ducks in a row. Just hope the DNO is open to informal enquires 🙂

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8 minutes ago, bontwoody said:

That sounds sensible, im just eager to get my ducks in a row. Just hope the DNO is open to informal enquires 🙂

Ours was at SP Manweb. I emailed their contact for our area and they phoned back the next day having already looked at our property. We had informal agreement a day or two later so I could plan things from that point. I cant speak highly enough of the service so far.

The one fly in the ointment is that all this was way back Feb/March time and they were busy then. I spoke to their engineer last week and he said for every application they send out they get 4 new enquiries come in. Service may have changed now.

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10 minutes ago, Dillsue said:

Ours was at SP Manweb. I emailed their contact for our area and they phoned back the next day having already looked at our property. We had informal agreement a day or two later so I could plan things from that point. I cant speak highly enough of the service so far.

The one fly in the ointment is that all this was way back Feb/March time and they were busy then. I spoke to their engineer last week and he said for every application they send out they get 4 new enquiries come in. Service may have changed now.

That sounds highly likely given the lack of response from solar installers, Maybe things will calm down later in the year. I cant help thinking that for all the pain of fuel inflation, its given renewal generation and fuel efficiency a real shot in the arm.

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2 hours ago, bontwoody said:

OK, so I would need to have a seperate consumer unit and decide which circuits were battery driven and which grid driven. How exactly would you put them back on the grid if the batteries were dry?

I am going to wire my inverter/charger into the grid via input terminals, so if there is no PV coming in and no battery capacity, it just draws on the grid and comes straight out the output side into my consumer unit.

 

Technically it is "off-grid" but fully connected too, I can of course simply isolate this supply if I want to go truly off-gird. If I do my sums right and the sun works, I should never actually go over to grid.

 

 

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6 hours ago, Carrerahill said:

I am going to wire my inverter/charger into the grid via input terminals, so if there is no PV coming in and no battery capacity, it just draws on the grid and comes straight out the output side into my consumer unit.

 

Technically it is "off-grid" but fully connected too, I can of course simply isolate this supply if I want to go truly off-gird. If I do my sums right and the sun works, I should never actually go over to grid.

 

 

That sounds exactly the type of system Im looking for 🙂

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On 23/06/2022 at 10:48, TW9 said:

How would you avoid DNO approval? I thought as soon as you connect any generation to the grid they need to know about it.

Up to 16A you only need to give them notification, it has become apparent that most solar installers have not being doing this properly and the DNO's reaction has been zero. The installer does the MCS cert, the utility company accepts that as part of the SEG application and that is the end of it. DNO never gets told. 

 

Over 16A you need approval to go over 16A and then the DNO really only wants to know so they ensure the upstream network can handle the export, which for now will not be an issue but if you had 20 houses on a tranny phase protected by say a 600A BS88 - then if each house generated & exported 7.2kW then that would arguably be sitting right on the LV network design capacity.

 

If you want SEG then you need to go through the proper channels, if you just want some solar and plan to self-consume/store, maybe export a little bit, then I would just crack on and do it. 

 

 

 

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