If I was to wire a new house for an Inverter/Charger, what would be the best way to plan a single phase installation? My thoughts are as follows:

1. L/N from provider to Main Breaker.

2. From Main Breaker split L/N to Critical and Non-Critical loads. Non-Critical use provider power (L/N).

3. At Main Breaker split point, connect Ziehl-type device to Critical Loads connection and on to Inverter/Charger.

4. Inverter output (L2/N2) to Critical Loads on own Neutral and RCD etc.

5. Grid-Tied PV Inverter connect to Inverter/Charger Output to supply power to Critical Loads during power outage.

Any suggestions regarding the above?

Ingo

 

OK assuming single phase, and without going into wiring details:

I'd divide the loads types:

1. lights and security, because they are needed at night.+ whatever else is deemed essential, ( personal choice).

(You'd be prepared to run batteries for these loads at night in a power cut, so be cut-throat).

2. Loads that you want to use solar for ( geysers, pool pump, heaters, borehole pump, stove, slow cooker etc), stuff that needs to be run almost daily but isn't that fussy about what time of the day.

( These come on when your solar is pumping, maybe only tick over at other times of the day and be off during a power cut).

3. Everything else.

(Use whenever convenient and they'd be off during a power cut).

Then I'd develop my system to cope, once I knew what loads I was dealing with and when ( during the day) I was dealing with them.

Yip, the loads are divided into your suggestion. The heavy hitters are Pool, Stove etc and 'can' run off solar while provider power is On - I don't mind them being Off when there is a power failure so I combined #2 and #3 somewhat. Geysers are EV types so needs minimal power only for longish cloudy days.

The Zero Control point is the last point before the main breaker so can manage any feedback if there are excess solar.

Essentially, is there nothing special to be done on the wiring side as it's difficult/costly to change after the house is complete apart from splitting the loads? Would the below be correct? Or perhaps just run one N and L1 and L2 to save on cable cost from the provider DB to the House DB?

 

Can your inverter contribute to the entirety of your load?  Instead of splitting it either-side like you have drawn.

The idea being that the inverter can offset any load, not just some loads during the day.

No, that would be too costly and you never know when another heavy (non critical) load might be added to the equation. Would you suggest a different wiring given the current requirements?

What type of inverter/charger and PV inverter is it?

38 minutes ago, phil.g00 said:

Can your inverter contribute to the entirety of your load? 

Like grid tied, feed the entire house with the essential loads on batteries if the grid is off.

@Ingo what I friend of mine once told me, have 2 circuits per point, one dedicated to solar the other to grid. Maybe expensive initially, but over time, priceless.

2 minutes ago, phil.g00 said:

What type of inverter/charger and PV inverter is it?

Team Blue 

And the PV will be Fronius.

To answer T^3, I thought about that and is a good suggestion. I just want to drop the known loads without any hoo-haa like Pool, Geysers, Stove etc. Plugs are a HR nightmare, try telling someone you shouldn't plug your hairdryer into 'that' socket... But it can be managed.

36 minutes ago, Ingo said:

No, that would be too costly and you never know when another heavy (non critical) load might be added to the equation. Would you suggest a different wiring given the current requirements?

 

8 minutes ago, Ingo said:

Team Blue 

And the PV will be Fronius.

I thought as much, ( good choice), but the right Victron is well capable of passing through your entire supply onto two outputs.

One of which will be switched off if the grid is lost.

My understanding is that the inverter will assist both outputs when the grid is present though.

Why do you say this option is too expensive?

8 minutes ago, Ingo said:

And the PV will be Fronius.

Why a Fronius? Is it not cheaper to get MPPT/'s?

I settled after years on a 150/100. Why not go for a 250/100 - buy once and forget about it, add more panels as you need if you need.

14 minutes ago, Ingo said:

And the PV will be Fronius.

Wanna try an ABB on there? 

1 minute ago, phil.g00 said:

 

I thought as much, ( good choice), but the right Victron is well capable of passing through your entire supply onto two outputs.

 

Yes, I do that currently but the new house, flat actually, will use something smaller which doesn't have that second output. I thought of saving a bit not buying a Big Blue and wire the heavy loads straight to the utility power - they drop out on power failure anyway.

Quote

Why a Fronius? Is it not cheaper to get MPPT/'s?

 The Pool is a 'Day Runner' so grid tied might be more efficient not having to invert up to 230V. It also gives me the option to feed back excess power. Here where I am the feed-back is not as complicated as in CT.

3 minutes ago, Ingo said:

The Pool is a 'Day Runner' so grid tied might be more efficient not having to invert up to 230V. 

I'm not so sure that the efficiency would be wow! 

4 minutes ago, Ingo said:

I thought of saving a bit not buying a Big Blue

 Take a Multiplus II, and not a Fronius nor ABB, and go with MPPT's.

You can feed back with that setup, or not, your control. 🙂

And you don't need a Ziehl.

I see the  Current Automation, prices today:
Multiplus II 48/3000/35-32 is R 13 705.70 incl VAT
And if you go big once: Smartsolar 250/100 MC is R 11 693.20 incl VAT.

 

5 minutes ago, Ingo said:

Here where I am the feed-back is not as complicated as in CT.

If it is in SA, one day it is going to get complicated, unless Eskom slips more. 🙂 

2 minutes ago, The Terrible Triplett said:

I'm not so sure that the efficiency would be wow! 

Efficiency would definitely be lower that using straight from PV inverter.

3 minutes ago, The Terrible Triplett said:

And if you go big once: Smartsolar 250/100 MC is R 11 693.20 incl VAT.

For that price you are getting close to GT inverter prices without having to build DC combiner boxes. Inverter has that built in already.

2 minutes ago, anotherbrownbear said:

For that price you are getting close to GT inverter prices without having to build DC combiner boxes

Good point. See the 150/45 is R 6 465.30 incl

Also need the VenusGX ...

Any case, there was Fronius as an option, now there are ABB and MPPT's added. 🙂 

Maybe even go ABB / Fronius with a UPS as backup on the dedicated circuits.

All valid points. The Multi is the type of device I had in mind and I see now it has a small Aux output of 32A. It is cutting it close to an Oven, Pool, small aircon and then the dreaded hairdryer.

Without going for a bigger unit, would the 'two separate feeds' suggestion be the best? That would be future proof if another device is added to the heavy loads. What is the de facto standard when faced with unknown future heavy loads?

Just for info, once I have the HW ironed out I want to confirm the SW side, meaning use 10%-15% battery power at night and have 85%-90% available for power failures (load shedding). Have solar charge the batteries back to 100% and feed power back when available. In short, ESS.

If you can feed back, then feed as much solar back as possible without feeding power from batteries. Unless of course, your battery is very well price and cheaper to run than grid.

 

With regards to your load, unless you build a mansion and start using incandescent lighting again, 32A is plenty.

I run a 4 bed house with 4 people in on a 35A main breaker from council. Not even getting close to that. That includes my pumps for water supply.

12 hours ago, phil.g00 said:

I thought as much, ( good choice), but the right Victron is well capable of passing through your entire supply onto two outputs.

One reason I prefer not to put everything on the output side (even the second output, where you have one), is that when you do inverter firmware updates or anything that requires switching off the inverter or a VE.Bus reset, then it drops ALL your loads for a few seconds. So I much prefer to leave those other loads on the grid side, and use an energy meter to feed energy to them. Also, if you have a smaller Compact model, that is your only choice (and often cheaper than going up a model... though it has to be said that the MP-II is very competitive).

29 minutes ago, plonkster said:

One reason I prefer not to put everything on the output side (even the second output, where you have one), is that when you do inverter firmware updates or anything that requires switching off the inverter or a VE.Bus reset, then it drops ALL your loads for a few seconds. So I much prefer to leave those other loads on the grid side, and use an energy meter to feed energy to them. Also, if you have a smaller Compact model, that is your only choice (and often cheaper than going up a model... though it has to be said that the MP-II is very competitive).

Not if you have a flexible install like this. I started with Axpert and upgraded to Goodwe after a bad lightening strike.

13 hours ago, Ingo said:

Team Blue 

And the PV will be Fronius.

To answer T^3, I thought about that and is a good suggestion. I just want to drop the known loads without any hoo-haa like Pool, Geysers, Stove etc. Plugs are a HR nightmare, try telling someone you shouldn't plug your hairdryer into 'that' socket... But it can be managed.

So here is what I did and it is working well for me.

Each conduit feeding my plug sockets has 2 circuits (battery back up and eskom)

Some plugs are connected to the battery backup circuit (TV, Wi-Fi router etc) and some plugs are connected to the eskom supply which turns off during a grid failure.

In the main bedroom I have a double plug socket that has battery back up supply on the left hand side socket and eskom supply on the right hand side socket.

This way I can keep my cell phone charging when there is a power failure but the heater that is running in winter will turn off when the grid fails.

If you are concerned about people plugging large loads into the inverter sockets you could always install dedicated plug sockets for the inverter supply (the earth pin receptacle is a different shape.

I used the Major Tech VETI sockets as they allow you to have separate supplies on each socket of a double plug socket.

This seemed to work well for me, might be of some use to you?

3 minutes ago, virge said:

Not if you have a flexible install like this.

Yeah, you could also throw the changeover. That is true.

Impressive install 👍

Yes, the plan is to have different plugs (red UPS plugs) for different feeds to minimize the 'hairdryer issue' and to make it clear which devices will go down in the event of a failure.

For my install to materialise it took the knowledge and kindness of Jacques Schickerling who answered all my questions and a months of planning, then gettiung the parts, making the boards another 2 weeks. The installation took me 3 days, the hardest part was to transfer the back-up circuits from the old DB. The parts are not cheap but worth it because now I can install any inverter in less than 2 hours. You never know when trouble strikes. In my case the loong direct lightning strike on my roof, I had an ark on the roof for more than 7 seconds, flames and sparks everywhere, inverter completely fried also all my 12 x PVs damaged. It took me less than a minute to bypass the inverter and less than 2 hours to install the new inverter.

43 minutes ago, Ingo said:

... different plugs (red UPS plugs) ...

Just don't do what I did, caught myself putting red plugs onto Multiplugs ... that kinda defied the purpose of paying for and installing red plugs. 🤣

I starts very innocently. Just this one, for the wife, kids ... 

I feel your pain 😆