Should I be applying to the DNO to increase my output?

[wc1966]

I'm about to install a system is around 7.2kw with a south facing roof (not much shade), I'd expect absolute peak from these panels to be around 6.5kw.

I'm going for a 5kw GivEnergy Gen 2 inverter and a 9.5kw battery.

Would my correct understanding be if the panels were producing 6.5kw that 1500w would clip, 3.6kw would go to the grid and 1.4kw would be available for the house / EV charger etc?

With this set should I consider increasing my export limit, I'm assuming a 20-23p export will be available with the likes of Octopus Flux?

I have an Indra Smart Pro charger, any view how this compares with a Zappi which I understand can run in Eco mode? I'm also going with an Eddi diverter but thinking perhaps its not worth it,,,

 

[bladerunnerpv]

Yes, DC coupled Gen 2 has 5kW AC output power, so if you have more than that input from PV input (ignoring the efficiency) it will just dissipate as heat.

How much of the 5kW goes to the house depends on the demand from the house and your export preference. You will save more money from PV by prioritising daytime house use rather than exporting it.

Suggest you look at the Gen 3, the MPPT range is a bit better so will continue generating for a bit later in the day.

I don't have one myself, just checking the datasheet.

 

[binky]

I would probably go for a bigger inverter, undersizing inverters is ' old hat' advice based on old fashioned less efficient inverters.

 

[johnb2713]

I have an Indra Smart Pro charger, any view how this compares with a Zappi which I understand can run in Eco mode? I'm also going with an Eddi diverter but thinking perhaps its not worth it,,,

I have both Zappi and Eddi, the two work seamlessly together and are simple to setup from the app. Zappi can be set to how green the energy should be, I have mine set to 100% so it will only charge from excess solar and the scheduled times on the grid but you can set it to lower figures which allows some grid import as well. It monitors the export and when it hits 1.4kW or less if you have %green set, it will start the EV charging. This works with Eddi too, priorities set in the app eg car first, immersion second etc. in my case the immersion is fed with excess power until it reaches 1.4 kW, Zappi then takes over charging the car, when its done or the excess solar drops below 1.4kW it reverts back to immersion. It's an absolute dream to set up, really easy and you can see in an instant whats going on etc.



This was during one of the Octopus Intelligent peak time charging sessions, they take control of the car charging and supply at off peak rates during peak time period. I have my system configured so that when these periods are triggered, Home Assistant also starts everything else up, batteries charging, Immersion heating, heatpumps running. From the above 16.9kW importing from the grid, 2.4kW going to the immersion, 6.9kW to the car, 0.3kW to the solar Battery (it was almost 100%), and 7.3kW into the house. It's a really good system, Eddi is more expensive than some of the others but you get what you pay for.

 

[wc1966]

I would probably go for a bigger inverter, undersizing inverters is ' old hat' advice based on old fashioned less efficient inverters.

Are you suggesting go for a bigger inverter and do the DNO application also?

On good days I can plug in the EV and take 1.4kw and with my background use negligible (typ 250w) most of the 3.6kw left can go to the grid.

Realistically will inexcess of 5kw generation be achieved that often, at the moment though I imagine I'd be seeing a fair bit of clipping

 

[wc1966]

I have both Zappi and Eddi, the two work seamlessly together and are simple to setup from the app. Zappi can be set to how green the energy should be, I have mine set to 100% so it will only charge from excess solar and the scheduled times on the grid but you can set it to lower figures which allows some grid import as well. It monitors the export and when it hits 1.4kW or less if you have %green set, it will start the EV charging. This works with Eddi too, priorities set in the app eg car first, immersion second etc. in my case the immersion is fed with excess power until it reaches 1.4 kW, Zappi then takes over charging the car, when its done or the excess solar drops below 1.4kW it reverts back to immersion. It's an absolute dream to set up, really easy and you can see in an instant whats going on etc.

View attachment 15593

This was during one of the Octopus Intelligent peak time charging sessions, they take control of the car charging and supply at off peak rates during peak time period. I have my system configured so that when these periods are triggered, Home Assistant also starts everything else up, batteries charging, Immersion heating, heatpumps running. From the above 16.9kW importing from the grid, 2.4kW going to the immersion, 6.9kW to the car, 0.3kW to the solar Battery (it was almost 100%), and 7.3kW into the house. It's a really good system, Eddi is more expensive than some of the others but you get what you pay for.

Sounds like a great set up

Ahead of my install I've been doing a fair bit of analysis on tariffs ahead of my install. I'm considering whether with my set up its better for go for broke for export @23p with Octopus Flux March - October. Then flipping to Intelligent or Go November till February charging my battery and EV off peak. I'm torn whether the Eddi is worth it with gas due to drop to 7.5p/kw, though for the cost might just do it to future proof and you never know whats coming.

 

[binky]

Are you suggesting go for a bigger inverter and do the DNO application also?

You need to notify DNO regardless of the size of system.

Realistically will inexcess of 5kw generation be achieved that often, at the moment though I imagine I'd be seeing a fair bit of clipping

More often than you might think, but either way, why clip energy generated? Older inverters could drop to 70% efficiency. Today's inverters don't drop below 92%, so undersizing inverters to improve winter efficiency no longer makes any sense.

 

[johnb2713]

Sounds like a great set up

Ahead of my install I've been doing a fair bit of analysis on tariffs ahead of my install. I'm considering whether with my set up its better for go for broke out export @23p with Octopus Flux March - October. Then flipping to Intelligent or Go November till February charging my battery and EV off peak. I'm torn whether the Eddi is worth it with gas due to drop to 7.5kw.

You do have to consider all the implications with EDDI, gas dropping in price is good news but you have to consider boiler efficiency (typically 80%), losses in the pipework to your tank, cost of running the pumps and controls. Add to this the efficiency of EDDI to use all of the surplus solar that youre getting paid a low rate for. For me it works well, for others it may not.

 

[wc1966]

You do have to consider all the implications with EDDI, gas dropping in price is good news but you have to consider boiler efficiency (typically 80%), losses in the pipework to your tank, cost of running the pumps and controls. Add to this the efficiency of EDDI to use all of the surplus solar that youre getting paid a low rate for. For me it works well, for others it may not.

Yes there are a lot things in play and things can change in the energy market.

I'm kicking myself as I got an EV charger installed free of charge by a car leasing company but paid little attention at the time as solar wasn't on my radar. From the sounds of things the Zappi would have probably been a better option than the Indra Smart Pro.

I wonder whether its worth going for an off grid switch, though my solar installer doesn't seem keen on going there

 

[binky]

Going off grid is more pipe dream than realistic. Energy savings and self consumption is the target, although charging/ topping up batteries off peak is simple enough to do and offers good savings. Part of the reason I would go for a larger inverter, so it can cope with more of the house demand, ergo, you buy less from the grid.

 

[wc1966]

Going off grid is more pipe dream than realistic. Energy savings and self consumption is the target, although charging/ topping up batteries off peak is simple enough to do and offers good savings. Part of the reason I would go for a larger inverter, so it can cope with more of the house demand, ergo, you buy less from the grid.

With a 7.2kw system, how big should i go. As things stand its a 5kw gen 2 (may go g3) inverter

 

[binky]

With a 7.2kw system, how big should i go. As things stand its a 5kw gen 2 (may go g3) inverter

Ideally 7kw, but at least 6kw. I'm not sure what sizes are available in that range. 5 kw is roughly 30% but undersized, the acceptable level for old inverters was only ever 20%

 

[wc1966]

Ideally 7kw, but at least 6kw. I'm not sure what sizes are available in that range. 5 kw is roughly 30% but undersized, the acceptable level for old inverters was only ever 20%

Not sure GivEnergy go past 5kw, unless I went for 2 x 3.6kw. But quite a bit of extra cost, I guess I have to consider how much power I will miss out on. Might be better off investing in regular solar panel cleaning (I know many don't bother)

 

[bladerunnerpv]

Two ac coupled 3.6 can be linked and communicate iirc, so they shouldn't 'fight', however there is only 2.5kw from battery from single unit iirc, it supposed to scale with no. of inverters I think.

 

[binky]

Not sure GivEnergy go past 5kw, unless I went for 2 x 3.6kw. But quite a bit of extra cost, I guess I have to consider how much power I will miss out on. Might be better off investing in regular solar panel cleaning (I know many don't bother)

They do a 6kw but not a7kw. Nothing special about Givenergy, there's plenty of other makes of inverter.

 

[johnb2713]

With a 7.2kw system, how big should i go. As things stand its a 5kw gen 2 (may go g3) inverter

My system has 6.5kW of panels and a 6kW Growatt inverter along with 7kWh Growatt battery. I was most annoyed to find our system kept importing from the grid when combinations of loads were on - washing machine & Tumble Drier, Kettle and oven etc. I added another inverter and battery (Victron) to bring my total inverter power to 9kW and batteries up to 21kWh, now we only use a miniscule amount of peak energy, less than 1kWh per day. You really should seriously consider the inverter size if like me, you want to avoid the expensive energy. All of my energy is now 7.5p or free.

 

[wc1966]

My system has 6.5kW of panels and a 6kW Growatt inverter along with 7kWh Growatt battery. I was most annoyed to find our system kept importing from the grid when combinations of loads were on - washing machine & Tumble Drier, Kettle and oven etc. I added another inverter and battery (Victron) to bring my total inverter power to 9kW and batteries up to 21kWh, now we only use a miniscule amount of peak energy, less than 1kWh per day. You really should seriously consider the inverter size if like me, you want to avoid the expensive energy. All of my energy is now 7.5p or free.

Sounds like you have a high degree of independence, what is your annual production / panel aspect / shading like?

 

[johnb2713]

Sounds like you have a high degree of independence, what is your annual production / panel aspect / shading like?

We have 10 panels south facing, 6 panels west facing, no shading, generated 6.1 MWh over the last 12 months.

 

[Joules]

I'm about to install a system is around 7.2kw with a south facing roof (not much shade), I'd expect absolute peak from these panels to be around 6.5kw.

I'm going for a 5kw GivEnergy Gen 2 inverter and a 9.5kw battery.

Would my correct understanding be if the panels were producing 6.5kw that 1500w would clip, 3.6kw would go to the grid and 1.4kw would be available for the house / EV charger etc?

With this set should I consider increasing my export limit, I'm assuming a 20-23p export will be available with the likes of Octopus Flux?

I have an Indra Smart Pro charger, any view how this compares with a Zappi which I understand can run in Eco mode? I'm also going with an Eddi diverter but thinking perhaps its not worth it,,,

As far as I am aware the DNO approves the install based upon the size of the installed inverter not what panels you have. If an extra inverter is required they need to know so they can do an infrastructure impact assessment.

 

[johnb2713]

I'm about to install a system is around 7.2kw with a south facing roof (not much shade), I'd expect absolute peak from these panels to be around 6.5kw.

Do you mean youre actually installing it yourself or youre employing contractors to do it? If youre wanting to export energy it's nigh on impossible without an MCS certificate.