I am new to all this and looking for feedback on my 'off grid' system

[dangermouse]

The 3.6kW one is the biggest you can have without asking permission form the DNO (power company). 3.6Kw is the maximum power the inverter can inject into the grid, this can come from solar or batteries or a mixture of the two. Imagine your panels are producing 2kW and your house load is 4kW. Then you would get 2kW from the solar, 1.6kW from the batteries, and 400W from the grid. The extra 600W will significantly reduce how much peak grid power you consume.

Right I think I get it. When you say "3.6Kw is the maximum power the inverter can inject into the grid" that doesn't just mean exporting power to the grid, but also powering my house circuits that are linked to the grid-tied output of the inverter?

And the 3kW rated "back up" output of the inverter is the purely battery powered output that continues to work in a power cut. Implying that the grid-tied output will not work in a power cut, even if I have PV generation and/or full batteries? Because the inverter is not allowed to energise the grid in a power cut situation?

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

[Stinsy]

Right I think I get it. When you say "3.6Kw is the maximum power the inverter can inject into the grid" that doesn't just mean exporting power to the grid, but also powering my house circuits that are linked to the grid-tied output of the inverter?

And the 3kW rated "back up" output of the inverter is the purely battery powered output that continues to work in a power cut. Implying that the grid-tied output will not work in a power cut, even if I have PV generation and/or full batteries? Because the inverter is not allowed to energise the grid in a power cut situation?

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

Correct.

The inverter varies how much it "injects" to try and keep your usage at zero. It's max is 3.6kW so if you use more than that, the rest comes from the grid.

[Joeboy]

The 3.6kW one is the biggest you can have without asking permission form the DNO (power company). 3.6Kw is the maximum power the inverter can inject into the grid, this can come from solar or batteries or a mixture of the two. Imagine your panels are producing 2kW and your house load is 4kW. Then you would get 2kW from the solar, 1.6kW from the batteries, and 400W from the grid. The extra 600W will significantly reduce how much peak grid power you consume.

Right I think I get it. When you say "3.6Kw is the maximum power the inverter can inject into the grid" that doesn't just mean exporting power to the grid, but also powering my house circuits that are linked to the grid-tied output of the inverter?

And the 3kW rated "back up" output of the inverter is the purely battery powered output that continues to work in a power cut. Implying that the grid-tied output will not work in a power cut, even if I have PV generation and/or full batteries? Because the inverter is not allowed to energise the grid in a power cut situation?

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

You really should contact the inverter supplier on this. It reads as if you hope that the 3.6kW grid connected side and the 3kW back up can be live at the same time? There are ways to extract more power with another inverter running directly off your batteries while the main grid tied inverter gives you the 3.6kW but it is potentially complicating the discussion and could damage the batteries.
There are many ways to do this but it will come down to how much you want to achieve and how much you want to spend.

The point I hope to get across is that a single 3.6kW capable hybrid inverter is quite a bottleneck. In saying that you may already live quite a parsinimous lifestyle. I just wouldn't want to see you spend hard earned cash on something you might regret quite quickly. Also, is 2.4kWh the most you can squeeze onto the roof? How's your garden space and orientation, we also like groundmounts here or even shed mounts. Nothing quite beats the raw HP of excessive PV, it gets you through marginal days handily.

[Stinsy]

The 3.6kW one is the biggest you can have without asking permission form the DNO (power company). 3.6Kw is the maximum power the inverter can inject into the grid, this can come from solar or batteries or a mixture of the two. Imagine your panels are producing 2kW and your house load is 4kW. Then you would get 2kW from the solar, 1.6kW from the batteries, and 400W from the grid. The extra 600W will significantly reduce how much peak grid power you consume.

Right I think I get it. When you say "3.6Kw is the maximum power the inverter can inject into the grid" that doesn't just mean exporting power to the grid, but also powering my house circuits that are linked to the grid-tied output of the inverter?

And the 3kW rated "back up" output of the inverter is the purely battery powered output that continues to work in a power cut. Implying that the grid-tied output will not work in a power cut, even if I have PV generation and/or full batteries? Because the inverter is not allowed to energise the grid in a power cut situation?

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

You really should contact the inverter supplier on this. It reads as if you hope that the 3.6kW grid connected side and the 3kW back up can be live at the same time? There are ways to extract more power with another inverter running directly off your batteries while the main grid tied inverter gives you the 3.6kW but it is potentially complicating the discussion and could damage the batteries.
There are many ways to do this but it will come down to how much you want to achieve and how much you want to spend.

The point I hope to get across is that a single 3.6kW capable hybrid inverter is quite a bottleneck. In saying that you may already live quite a parsinimous lifestyle. I just wouldn't want to see you spend hard earned cash on something you might regret quite quickly.

I have pretty hight energy requirements (25-30kWh per day) and a 3.6kW hybrid inverter is plenty for me!

[Joeboy]

Right I think I get it. When you say "3.6Kw is the maximum power the inverter can inject into the grid" that doesn't just mean exporting power to the grid, but also powering my house circuits that are linked to the grid-tied output of the inverter?

And the 3kW rated "back up" output of the inverter is the purely battery powered output that continues to work in a power cut. Implying that the grid-tied output will not work in a power cut, even if I have PV generation and/or full batteries? Because the inverter is not allowed to energise the grid in a power cut situation?

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

You really should contact the inverter supplier on this. It reads as if you hope that the 3.6kW grid connected side and the 3kW back up can be live at the same time? There are ways to extract more power with another inverter running directly off your batteries while the main grid tied inverter gives you the 3.6kW but it is potentially complicating the discussion and could damage the batteries.
There are many ways to do this but it will come down to how much you want to achieve and how much you want to spend.

The point I hope to get across is that a single 3.6kW capable hybrid inverter is quite a bottleneck. In saying that you may already live quite a parsinimous lifestyle. I just wouldn't want to see you spend hard earned cash on something you might regret quite quickly.

I have pretty hight energy requirements (25-30kWh per day) and a 3.6kW hybrid inverter is plenty for me!

Is your main PV system running off its own inverter or all off a single hybrid? I don't want to put the guy off but just make sure he sees the limits. As a comparison, my system could theoretically output 35kWh from the PV and 86.4kWh from the batteries. 121.5kWh on its best day. In no way a brag, just pointing out bottlenecks. They are always there!

[Stinsy]

You really should contact the inverter supplier on this. It reads as if you hope that the 3.6kW grid connected side and the 3kW back up can be live at the same time? There are ways to extract more power with another inverter running directly off your batteries while the main grid tied inverter gives you the 3.6kW but it is potentially complicating the discussion and could damage the batteries.
There are many ways to do this but it will come down to how much you want to achieve and how much you want to spend.

The point I hope to get across is that a single 3.6kW capable hybrid inverter is quite a bottleneck. In saying that you may already live quite a parsinimous lifestyle. I just wouldn't want to see you spend hard earned cash on something you might regret quite quickly.

I have pretty hight energy requirements (25-30kWh per day) and a 3.6kW hybrid inverter is plenty for me!

Is your main PV system running off its own inverter or all off a single hybrid? I don't want to put the guy off but just make sure he sees the limits. As a comparison, my system could theoretically output 35kWh from the PV and 86.4kWh from the batteries. 121.5kWh on its best day. In no way a brag, just pointing out bottlenecks. They are always there!

I'm running everything off a single 3.6kW hybrid inverter.

The problem with two inverters is: you double the price, double the space, and incur the complexity of a DNO application.

Sure you get more ultimate power from two inverters because you can have the full power of your solar inverter AND the full power of your battery inverter exporting simultaneously. And if you want to add a battery system to an existing FiT system then you have to go the dual-inverter route.

However he uses less than 20% of the electric that I do, so I'm very confident he'll be fine on a single 3.6kW inverter. And if he did need more power than that (for example he had a HP) then I'd recommend a 5kW hybrid rather than two inverters.

[dangermouse]

So, it might be a sensible idea to add a second consumer unit connected to the "back up" output, and connect, say, my freezers to it? But this could be done at a later time if I decide to.

You really should contact the inverter supplier on this. It reads as if you hope that the 3.6kW grid connected side and the 3kW back up can be live at the same time?

I'll have to check the user guide for that inverter, and it's not an important feature, just a thought.

The point I hope to get across is that a single 3.6kW capable hybrid inverter is quite a bottleneck. In saying that you may already live quite a parsinimous lifestyle. I just wouldn't want to see you spend hard earned cash on something you might regret quite quickly. Also, is 2.4kWh the most you can squeeze onto the roof? How's your garden space and orientation, we also like groundmounts here or even shed mounts. Nothing quite beats the raw HP of excessive PV, it gets you through marginal days handily.

My roof is 4.2 x 5.8 metres. I am going to speak to a local roofer who fits panels to get the facts, but meanwhile I was reading "The Town and Country Planning (General Permitted Development) (England) Order 2015" (a dry read), and I got the idea from there that you had to leave 1m of roof space around the panels. However I see after re-reading the relevant parts (part 14) that that regulation is for non-domestic properties.

With that in mind I think I can get 3x3 panels on the roof, so 3.6kW in total if I use 400W panels.

[Oldgreybeard]

Yes, panels can be a lot closer to the edge of the roof than 1m. Ours are right at the very bottom of the roof, and no more than about 300mm from the sides and ridge.

Worth getting as much up there as possible, as one of the highest costs is the scaffolding, and that's the same no matter how many panels you install.

[dangermouse]

I have pretty hight energy requirements (25-30kWh per day) and a 3.6kW hybrid inverter is plenty for me!

This is reassuring, thank you. We really do use 5.2kWh per day, averaged over the year. Obviously it will be a bit higher in winter, but with gas heating, probably not too much.

I'm prepared to make a few minor lifestyle adjustments anyway, for example getting a lower power kettle, using the 1.2kW air fryer instead of the 2.5kW oven.

[Joeboy]

Yes, panels can be a lot closer to the edge of the roof than 1m. Ours are right at the very bottom of the roof, and no more than about 300mm from the sides and ridge.

Worth getting as much up there as possible, as one of the highest costs is the scaffolding, and that's the same no matter how many panels you install.

For me, it's get all the HP you can on the roof(s) in one fell swoop. Go from there. There is always a way to shade the HP whether its edge rules or the dynamic between pv efficency vs cost. Nonetheless, play the game to maximise out that first step OP. Do all the homework on the various panels available