Solar panels and battery - any real world recommendations?

Jonathan spectra said:
Since the revamp of G99's iv never been charged a fee off northern powergrid, where have you seen this?

The only DNO I know which charges a fee at the moment is SP Energy Networks if a G99 sgi fails the initial fast track assessment. G99 A1-1 will 100% be a fee with SPEN as it goes straight to full works
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Yes, with it being G99 A1-1 (Inverter is 12kW so cannot do a fast track) it also goes to full works on Northern powergrid too. So £990 + VAT for an LV generation quotation up to 50kW.

Connection Offer Expenses | Northern Powergrid

www.northernpowergrid.com www.northernpowergrid.com

I think it started in May 2025.
 
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reef said:
Yes, with it being G99 A1-1 (Inverter is 12kW so cannot do a fast track) it also goes to full works on Northern powergrid too. So £990 + VAT for an LV generation quotation up to 50kW.

Connection Offer Expenses | Northern Powergrid

www.northernpowergrid.com www.northernpowergrid.com

I think it started in May 2025.
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I didn't get charged 2 months ago but ill give them a call tomorrow and find out if it's now implemented.

I'm still waiting for ENWL to start charging a fee now SP have bought them out and I imagine more DNOs will charge soon.
 
Ron-ski said:
Just to clarify, that's if you replace the existing FITS inverter with a hybrid, not fit a separate hybrid inverter.
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Jonathan spectra said:
Correct.

What's the reason for fitting a hybrid Inverter over an ac coupled?
I've done hybrid Inverters set up as ac coupled before as battery upgrades but that's just so we could use a 5kW as opposed to ac coupleds which are usually around 3.68kW.
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Thanks both.

We are only installing batteries and inverter (AC coupled). We already have a PV system with FIT, which we are not planning to change.
I'd asked on these forums if it would make sense to put in a hybrid inverter (but use it as an AC inverter) instead of just an ac inverter. The spec between the hybrid and ac only inverters appears to be identical other than the extra bits for pv inputs (@reef said MC4 ),and the cost difference is negligible. As we may add another pv array in the future I thought it might make sense to install a hybrid now (Fox ESS H1 G2, 6KW hybrid inverter).
 
We were leaning towards Project Green (Kent based) but Little Green Energy Company and Array Electrics are now talking about price matching. Lets go.

Edit - claws are out. Array Electrics just messaged saying 'they're well aware of the other two as many clients get cheaper quotes from them, however once they have dug a little deeper into the companies themselves, they soon realise that there are reasons why they are cheaper and choose to go with Array Electrics'. Time for a call.
 
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Right - so I've got an install date for the following system:

  • 26 Aiko panels over 3 different roofs
  • 12kW Sigenstor Inverter
  • 2x Sigenergy 12kWh batteries
  • Sigen EV AC Charger 7 kW 4G
  • Bird proofing etc. etc.
  • £16k

I'm curious to hear what you guys think of the battery capacity as compared with my consumption over the past 12 months (we switched on an ASHP in October last year and are off the gas grid entirely now!). With only 24kWh storage are we setting ourselves up badly from the start? Below is a chart of average daily electricity consumption and peak daily use by month. Very limited consumption in the night time.

ydMbXqL.png


There's still time to tweak battery sizes if I need to.

Thanks!
 
Do you have an EV?

Most ASHP users switch to Cosy tariff in the winter.

12kWh is probably enough for a start. If down the line you discover your electric bill is too high in the winter, it's very easy to add an extra battery to the stack.

But if you can afford it - you can switch to the new Sigenergy 10 batteries (that are actually 8.76kWh) - with 2 you'll have something like 17.5kWh usable capacity.
 
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At that price I'd see how it goes this winter, should be minimal cost to fit one later but maybe worth asking your installer what it would cost if done later compared to now.

SkyTerran said:
You're right - it may be 24kWh total. I don't think I've seen a 12kWh Sigenstor battery.
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I hadn't either, I Googled to check prior to posting.
 
Marakith said:
Right - so I've got an install date for the following system:

  • 26 Aiko panels over 3 different roofs
  • 12kW Sigenstor Inverter
  • 2x Sigenergy 12kWh batteries
  • Sigen EV AC Charger 7 kW 4G
  • Bird proofing etc. etc.
  • £16k

I'm curious to hear what you guys think of the battery capacity as compared with my consumption over the past 12 months (we switched on an ASHP in October last year and are off the gas grid entirely now!). With only 24kWh storage are we setting ourselves up badly from the start? Below is a chart of average daily electricity consumption and peak daily use by month. Very limited consumption in the night time.

ydMbXqL.png


There's still time to tweak battery sizes if I need to.

Thanks!
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24kwh is probably more than enough IMO.

I have an EV, 6kw ASHP a 13.5kwh battery and 10kwhp of solar split east/west (so **** in winter), my average grid import costs in December and January on IOG was 10p/kwh.

I've just pulled up my stats for December, I used 1200kwh in total (~40kwh/day), 701 was direct use the grid (of which 300 went into the EV and 400 was the house), 408 went via the battery and 91kwh from solar.

The objective is not zero peak time usuage, its lowest cost and quickest payback so the average import cost is key. Adding more will likely reduce your return on investment.

If your average import cost breaches 12p/kwh on IOG then switch to Cosy until your consumption drops back again. Adding more battery is never going to be cost effective vs using a tariff like cosy for 6-8 weeks of the year - realistically thats all you'll probably need, if that.

Remember you are only saving 5p/kwh by adding more battery compared to switching to Cosy (3.5p if you are on 'regular' Go), thats a lot of 5p's to make up from a £3000 battery. Yes I used some peak time electric in winter but not enough to even consider switching to Cosy let alone add more battery. Your solar will produce far more than mine in winter is some of it is south facing which mitigates the need for batteries even more.

I run the heat pump harder than needed over night to pre-warm the hose and then cost through the day on as low power as possible, rinse and repeat. It uses more energy but focuses it into the 7p period. If I was on cosy, I would switch tactics to maximum effciency as you can charge the battery 3 times a day.
 
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Marakith said:
Right - so I've got an install date for the following system:

  • 26 Aiko panels over 3 different roofs
  • 12kW Sigenstor Inverter
  • 2x Sigenergy 12kWh batteries
  • Sigen EV AC Charger 7 kW 4G
  • Bird proofing etc. etc.
  • £16k

I'm curious to hear what you guys think of the battery capacity as compared with my consumption over the past 12 months (we switched on an ASHP in October last year and are off the gas grid entirely now!). With only 24kWh storage are we setting ourselves up badly from the start? Below is a chart of average daily electricity consumption and peak daily use by month. Very limited consumption in the night time.

ydMbXqL.png


There's still time to tweak battery sizes if I need to.

Thanks!
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What company and part of London?
 
Marakith said:
It's this one: https://www.powerland.co.uk/collect...roducts/sigenergy-sigenstack-battery-12-0-kwh
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I would check this. I don't think the Sigenergy 12.0kWh battery works with the inverter that goes on top of the stack. The 12kWh model uses a battery controller that links to a standalone hybrid inverter. These are only up to a 6kW model on single phase (Sigenstack model)

I think the 8-12kW Sig hybrid inverters on single phase can only be paired with the 5, 6, 9 and 10(9)kW batteries (Sigenstor model).
 
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At this price, I assumed the quote is for two 6kWh batteries.

Two 12kWh batteries + 26 panels + scaffolding for 3 roofs + EV charger + 12kW inverter for £16k would be an amazing deal.

I think reef is right - the 12kWh batteries are an older model, that doesn't fit in the new Sigenergy stack.
 
Just did a bit of googling, it does require a seperate from the stack inverter, the 12kW inverter is also a 3 phase inverter, so I presume that's 4kW per phase.

I wonder if @Marakith is aware of this, and has a 3 phase supply.
 
Ron-ski said:
Just did a bit of googling, it does require a seperate from the stack inverter, the 12kW inverter is also a 3 phase inverter, so I presume that's 4kW per phase.

I wonder if @Marakith is aware of this, and has a 3 phase supply.
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This conversation has been quite illuminating. Have asked the installer and I'll let you guys know what happens.
 
Looks like I'm finally close to getting to Export. Just checked my account with Octopus and even though it's slightly confusing (two electricity), I should be switched on by Saturday (6th Sept)

 
The application process for export at Octopus is misleading. When one applies initially they get a page like this:

--------------------------------------------------------------------------------------------------------------------------------------------------------

Thanks for joining​

Outgoing Octopus!​

We'll email you all the details of your switch.
A smart house with solar panels and wind turbines

What happens next?​

1

Hang tight while we connect to your smart meter​

It generally takes us around 14 days so we can read it remotely - whether it's one we've just installed, or one we're taking over after you switch to us.
2

Once we're connected, we will set up your export​

When we are receiving your meter readings, we will contact the DNO to set up your MPAN and configure your smart meter. This can take up to 6 weeks.
3

We will let you know when your export is sorted in the meantime you're good to go!​

Your tariff will change automatically to Outgoing Octopus. You should see the change straight away on your online account.

----------------------------------------------------------------------------------------------------------------------------------------------------

Point 3 sounds as if one is ready to start exporting and be paid, but that's not the case.
 
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Had 2 site surveys yesterday. One company say they can fit 8 panels on our 2 roofs and the other say they can fit 12, both visits were by their installer/electricians rather than a sales person.

One company are new in their current format (apparently 2 directors fell out in the previous outfit and so a number of the team formed the new company) and have fitted 68 residential installations in their first 9 months. This worried me slightly but their electrician/installer did a good job alleviating those worries about after care support and monitoring, plus I spoke to a client of theirs (he had a 100 panel system lol) who spoke very highly of them (pinch of salt obviously). The other company has been around a good while longer and seem just as good. Something I did pick up on yesterday from another company was how good HEIS actually is, he suggested the claim system is not good and I checked this thread which also suggest it might be more for show/customers have a hard time navigating. However, the 12 panel company do accept CC.





It's hard to ignore the 12 panel offer as that includes the Gateway. It would be £13,600 if we included in the second/lower quote.
 
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If you're located in London, the first one is a good offer. These are the very latest solar panels and battery. If you're not getting power cuts, you can save the money for a gateway.

I'd ask what the price is for a Tesla Powerwall 3 - now that's available with or without a gateway as well.
 
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