Solar Installation

[ericmark]

My biggest gain was the battery and using off-peak supplies, you can't do that without an inverter, so you may as well have solar panels as well, and the solar panels reduce the size of battery required. The South-West is the important angle, as it is evening when one is likely to run out of battery. But this

is typical state of charge curve for the battery, the drop 5 am to 12 noon rarely gets near to the 10% cut off point, the evening it happens less now with 6.4 kWh to what it did with 3.2 kWh, but that curve can easy hit the 10% cut off point (reserved for UPS in case of power failure) before end of day. Yesterday for example ran out of battery before end of day, and unlikely any amount of solar panels can help when there is a lack of sun.

It is easy to miss judge the day, showing all factors we did do some cooking which did not help, but there is a balance, my batteries have a guarantee for 12 years, so need to pay back in that time, solar panels can last a lot longer, so to have enough battery not to ever use peak power would not pay, I expect as the days get shorter to have more and more days when the battery does not last out, I with my system have an option of 1 to 4 batteries, at fitted £1,200 each, and they are 3.2 kWh each, one was essential, but as to second, waited a year to see how it went, then got the second, once sure it would pay for its self. I don't think will ever be worth getting a third or forth unless I get more payment for export to what I pay for off-peak.

 

[Doug99]

I've been advised that as a domestic user, I can only export 3Kw of excess energy to the grid.
If I install a 4Kw system with a 9Kw battery, how is the export regulated?

 

[Doug99]

Lots of hardware and range of options being proposed.

I'm considering the following:
10 x Tiger Neo N-Type 54HL-4R- B panels - 4.4Kw - (I've suggested optimisers for all panels due to partial shading)
1 x SigenStor EC 4.0 SP Energy Controller
1 x SigenStor Battery with LED - Bat 8.0

Anyone have any experience of this hardware?

Provider is a local company who installed a different system to a neighbour and proposed quotes are significantly better than national brand providers.

Cheers

Doug

 

[Why Not Indeed]

That's BS or an over-simplification. I have permission from my DNO to export 5kVA, and I am a domestic user.

Only your equipment can limit the export. It's common to see a 3.8kW export limit setting on inverters to fit in with G98. My system is 5.6kWp so very rarely do I export over 5kW.

G98 is a 16A [3.8kW] limit and only requires notification.

National Grid - Micro generation single (G98)

National Grid Electricity Distribution is the regional electricity distribution division of National Grid.

connections.nationalgrid.co.uk

G99 requires permission and more paperwork. Perhaps your supplier tried the G99 route and your DNO said you could only export so much due to some local infrastructure issue. But the "domestic" excuse can't be relevant.

 

[DetlefSchmitz]

I've been advised that as a domestic user, I can only export 3Kw of excess energy to the grid.
If I install a 4Kw system with a 9Kw battery, how is the export regulated?

Haven't read the rest of this thread.

Firstly, who told you this? The DNO are the only people who can decide what the limit is. Was it them?

Secondly the Inverter should be settable to limit the export, below what the panels are specified as, but the DNO may have different views as to whether that is ok.

 

[Doug99]

Haven't read the rest of this thread.

Firstly, who told you this? The DNO are the only people who can decide what the limit is. Was it them?

Secondly the Inverter should be settable to limit the export, below what the panels are specified as, but the DNO may have different views as to whether that is ok.

It was a neighbour who mentioned the 3Kw limit.
Once I decide what system to install, I'll seek clarification from the provider.

 

[ericmark]

When we first looked at solar, and you got paid by the rating of the panels rather than what was actually exported, there were limits to array sizes, and we found different installers used different interpretation of the rules.

 

[DetlefSchmitz]

When we first looked at solar, and you got paid by the rating of the panels rather than what was actually exported,

I seriously question that that ever happened.

You might be confusing it with deemed export (50% of that generated).

 

[ericmark]

I seriously question that that ever happened.

You might be confusing it with deemed export (50% of that generated).

Yes, possibly, it resulted in items like the iboost+ which today don't really help, would be better to use off-peak.

 

[DetlefSchmitz]

would be better to use off-peak.

It would be even better if you started getting paid for export.

 

[ericmark]

Yes that is on going, still trying to sort it out. Today looking at solar production since clocks went back, and when off peak runs has changed I realise last year did not have a smart meter, so no off peak, the result today is one looks at the battery slowly discharging in the morning. I realise some days I will never recharge the battery during the day, good in one way as it means not giving away energy, but also means one will likely run out of battery as I did yesterday so one is looking at use v battery size.
Last month we clearly got it wrong we did not match the use to solar production, theroy is OK, but in practice if there is washing to be done, one want to do it, and on dull cool days one wants a hot meal, so even with double the battery to what we had last year, still not getting through the day with out using some peak power.

So 2023 and 2024 but does not show how much peak and off peak, not counting standing charge 2024 month 10 bill £39.39 for 282.26 kWh so either solar or smart meter is out a bit, but average of 14p per kWh I would say around 63.183 kWh peak and 219.077 kWh off peak in October 2024. Second battery fitted 15th Oct 2024 so really need to work it out for ½ month, but as the sample gets shorter more down to weather than how battery has helped. And BG app gives day or month, not ½ month.

Before second battery it was around 50% peak and off peak, after around 18% Peak and 82% off peak each battery around 3.2 kWh. Clearly moving into winter so 15 days used to get average, which could be as much to weather as second battery, but unlikely.