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What crazy nonsense are inverter limits and why are they imposed?

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Transparent
(@transparent)
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My apologies @batpred I overlooked that you'd already I identified your DNO as being UKPN.

So you are more likely to be in an area where 5kW export could be permitted.

Even so, the ENA guidelines do not allow the installer to set the export limit using the inverter's inbuilt firmware.
Only Sunsynk products have approval for such operation.


This post was modified 3 weeks ago by Transparent

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(@old_scientist)
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Posted by: @transparent

My apologies @batpred I overlooked that you'd already I identified your DNO as being UKPN.

So you are more likely to be in an area where 5kW export could be permitted.

Even so, the ENA guidelines do not allow the installer to set the export limit using the inverter's inbuilt firmware.
Only Sunsynk products have approval for such operation.

Tesla do too, in their PW3, but that's an all-in-one inverter/battery solution.

 


Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.


   
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Toodles
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@old_scientist And the Powerwall 2 has the same facility. I am able to export to a somewhat higher limit of ‘No Limit’ according to my installer! I have exported at something over 14 kW with the combined   battery and solar contributions. This I have done a few times when Octopus Energy have encouraged me to do so! Rewards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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(@agentgeorge)
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@toodles that’s nigh on 50 Amps 🙂

you’d be melting the sub station if you tried that by me



   
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Toodles
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@agentgeorge My application was by via a G99; and it was based on having 8.1 kWp. of solar panels and 1 x Tesla Powerwall (13.5 kWh). I added the second 13.5 kWh of battery some months later; all the settings were made between my installer and SSEN and there was no haggling required on my part. I have no idea what ‘No Limit’ means in such a setup but there is very little solar ‘panellege’ in my vicinity and I am unsure which transformer is my local but there are a great number of dwellings around us. Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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(@agentgeorge)
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Is your setup off grid capable?



   
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Toodles
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@agentgeorge Yes, the system will detect and switch over to battery in a few milliseconds - not noticeable, no flickers or glitches but the Tesla app informs me of any and all off-line events. In the depth of winter, we could probably carry on with just battery for ~ 12 hours or so. In summer, we could go on for days I should think. Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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(@old_scientist)
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Posted by: @toodles

@agentgeorge My application was by via a G99; and it was based on having 8.1 kWp. of solar panels and 1 x Tesla Powerwall (13.5 kWh). I added the second 13.5 kWh of battery some months later; all the settings were made between my installer and SSEN and there was no haggling required on my part. I have no idea what ‘No Limit’ means in such a setup but there is very little solar ‘panellege’ in my vicinity and I am unsure which transformer is my local but there are a great number of dwellings around us. Regards, Toodles.

No limit simply means there is no limit placed on what you are able to export from your property, so you can export up to the limitation of the equipment. Presumably you'll also be limited by your fuse although we usually think about the fuse as limiting (protecting) what the property can draw from the grid rather than what can be exported.

As you have 2 x PW2's, and each can output 5kW, your two units will be able to output 10kW, and as these are AC coupled, I assume you can then additionally output up to the limit of your solar inverter (less whatever the house load may be). So it is quite possible you could have a peak output of around 14kW (~60A) if both batteries are in forced export and you have 4kW of solar at the time (or maybe the PW2 has peak output of 7kW, and you just happened to observe peak output rather than sustained output?)

 

 


This post was modified 3 weeks ago by Old_Scientist

Samsung 12kW gen6 ASHP with 50L volumiser and all new large radiators. 7.2kWp solar (south facing), Tesla PW3 (13.5kW)
Solar generation completely offsets ASHP usage annually. We no longer burn ~1600L of kerosene annually.


   
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Toodles
(@toodles)
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@old_scientist It is as you say ‘sustained’ output with 10 kW from the battery and ~ 4 kW from solar whilst the house also draws a few hundred Watts to run in the background. This is one of the reasons why I was not 100% sure that Octopus Intelligent Flux was the best option - maybe I can have a limit of perhaps 7.5 kW export set on the Gateway? Regards, Toodles.


Toodles, heats his home with cold draughts and cooks food with magnets.


   
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(@batpred)
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Posted by: @transparent

So you are more likely to be in an area where 5kW export could be permitted.

Even so, the ENA guidelines do not allow the installer to set the export limit using the inverter's inbuilt firmware.

I am not planning to export at this stage, but am interested to find out what is needed to set an ENA acceptable export limit in this case. 

The inverter is a Solis S6-EH1P8K-L-PLUS. At some point home assistant may drive it, leveraging forecast green generation and by monitoring the battery, hopefully optimising all the assets. 

 

 



   
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(@batpred)
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Posted by: @scalextrix

In my view gas is 19th Century technology, I'll certainly be looking forward to throwing my carbon monoxide alarms away when the gas boiler is removed soon.

Still a long way for me. But not long ago I had this smell of gas and called Cadent.. The technology is so basic that they cut it off as soon as they can..

And I like the concept of having a gas fireplace as should the electricity fail on a storm, that could keep a room warm. But once I saw how quickly those guys lie their way and disconnect the gas to the whole house, it is obvious they assume the worst and fear the technology.    <end of rant> 

I am hoping to be able gradually move from gas to electricity before things start to need replacing. 

 



   
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Transparent
(@transparent)
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Posted by: @toodles

It is as you say ‘sustained’ output with 10 kW from the battery and ~ 4 kW from solar [...]

That will be producing significant losses due to phase imbalance at the local substation.

I cannot understand why SSES would be prepared to tolerate that.
It's clearly not "grid friendly".

 

SSES are now working on the next version of the RIIO Agreement which forms part of their Ofgem Licence.

RIIO-ED3 will be written in conjunction with the Regional Energy Strategic Plan organisation for their area.

Having targets set to reduce phase-imbalance is one of the issues I will be pushing hard to have in the new Agreement, which comes into force in April'27.


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